EX-10.4 8 d553197dex104.htm 2018 EQUITY INCENTIVE PLAN AND FORMS OF AWARD AGREEMENTS

EXHIBIT 10.4

SUTRO BIOPHARMA, INC.

2018 EQUITY INCENTIVE PLAN

1. PURPOSE. The purpose of this Plan is to provide incentives to attract, retain and motivate eligible persons whose present and potential contributions are important to the success of the Company, and any Parents, Subsidiaries and Affiliates that exist now or in the future, by offering them an opportunity to participate in the Company’s future performance through the grant of Awards. Capitalized terms not defined elsewhere in the text are defined in Section 28.

2. SHARES SUBJECT TO THE PLAN.

2.1. Number of Shares Available. Subject to Sections 2.6, 21, the automatic increase set forth in Section 2.4 and any other applicable provisions hereof, the total number of Shares reserved and available for grant and issuance pursuant to this Plan as of the date of adoption of the Plan by the Board, is Two Million Three Hundred Thousand (2,300,000) Shares, plus (a) any reserved shares not issued or subject to outstanding grants under the Company’s 2004 Stock Plan on the Effective Date (as defined below), (b) shares that are subject to stock options or other awards granted under the Company’s 2004 Stock Plan (the “Prior Plan”) that cease to be subject to such stock options or other awards by forfeiture or otherwise after the Effective Date, (c) shares issued under the Prior Plan before or after the Effective Date pursuant to the exercise of stock options that are, after the Effective Date, forfeited, (d) shares issued under the Prior Plan that are repurchased by the Company at the original issue price and (e) shares that are subject to stock options or other awards under the Prior Plan that are used to pay the exercise price of an option or withheld to satisfy the tax withholding obligations related to any award.

2.2. Lapsed, Returned Awards. Shares subject to Awards, and Shares issued under the Plan under any Award, will again be available for grant and issuance in connection with subsequent Awards under this Plan to the extent such Shares: (a) are subject to issuance upon exercise of an Option or SAR granted under this Plan but which cease to be subject to the Option or SAR for any reason other than exercise of the Option or SAR; (b) are subject to Awards granted under this Plan that are forfeited or are repurchased by the Company at the original issue price; or (c) are subject to Awards granted under this Plan that otherwise terminate without such Shares being issued. To the extent an Award under the Plan is paid out in cash rather than Shares, such cash payment will not result in reducing the number of Shares available for issuance under the Plan. Shares used to pay the exercise price of an Award or withheld to satisfy the tax withholding obligations related to an Award will become available for future grant or sale under the Plan. For the avoidance of doubt, Shares that otherwise become available for grant and issuance because of the provisions of this Section 2.2 shall not include Shares subject to Awards that initially became available because of the substitution clause in Section 21.2 hereof.

2.3. Minimum Share Reserve. At all times the Company will reserve and keep available a sufficient number of Shares as will be required to satisfy the requirements of all outstanding Awards granted under this Plan.

2.4. Automatic Share Reserve Increase. The number of Shares available for grant and issuance under the Plan will be increased on January 1 of 2019 through 2028 by the lesser of (a) five (5%) of the shares of all classes of the Company’s common stock outstanding on each December 31 immediately prior to the date of increase or (b) such number of Shares determined by the Board.

2.5. ISO Limitation. No more than Twenty Three Million (23,000,000) Shares shall be issued pursuant to the exercise of ISOs (as defined below) under the Plan.

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2.6. Adjustment of Shares. If the number of outstanding Shares is changed by a stock dividend, extraordinary dividend or distribution (whether in cash, shares or other property, other than a regular cash dividend) recapitalization, stock split, reverse stock split, subdivision, combination, consolidation, reclassification, spin-off or similar change in the capital structure of the Company, without consideration, then (a) the number and class of Shares reserved for issuance and future grant under the Plan set forth in Section 2.1, including shares reserved under sub-clauses (a)-(e) of Section 2.1, (b) the Exercise Prices of and number and class of Shares subject to outstanding Options and SARs, (c) the number and class of Shares subject to other outstanding Awards and (d) the maximum number and class of Shares that may be issued as ISOs set forth in Section 2.5 will be proportionately adjusted, subject to any required action by the Board or the stockholders of the Company and in compliance with applicable securities laws; provided that fractions of a Share will not be issued.

If, by reason of an adjustment pursuant to this Section 2.6, a Participant’s Award Agreement or other agreement related to any Award or the Shares subject to such Award covers additional or different shares of stock or securities, then such additional or different shares, and the Award Agreement or such other agreement in respect thereof, will be subject to all of the terms, conditions and restrictions which were applicable to the Award or the Shares subject to such Award prior to such adjustment.

3. ELIGIBILITY. ISOs may be granted only to Employees. All other Awards may be granted to Employees, Consultants, and Directors; provided such Consultants and Directors render bona fide services not in connection with the offer and sale of securities in a capital-raising transaction.

4. ADMINISTRATION.

4.1. Committee Composition; Authority. This Plan will be administered by the Committee or by the Board acting as the Committee. Subject to the general purposes, terms and conditions of this Plan, and to the direction of the Board, the Committee will have full power to implement and carry out this Plan, except, however, the Board will establish the terms for the grant of an Award to Non-Employee Directors. The Committee will have the authority to:

(a) construe and interpret this Plan, any Award Agreement and any other agreement or document executed pursuant to this Plan;

(b) prescribe, amend and rescind rules and regulations relating to this Plan or any Award;

(c) select persons to receive Awards;

(d) determine the form and terms and conditions, not inconsistent with the terms of the Plan, of any Award granted hereunder. Such terms and conditions include, but are not limited to, the Exercise Price, the time or times when Awards may vest and be exercised (which may be based on performance criteria) or settled, any vesting acceleration or waiver of forfeiture restrictions, the method to satisfy tax withholding obligations or any other tax liability legally due and any restriction or limitation regarding any Award or the Shares relating thereto, based in each case on such factors as the Committee will determine;

(e) determine the number of Shares or other consideration subject to Awards;

(f) determine the Fair Market Value in good faith and interpret the applicable provisions of this Plan and the definition of Fair Market Value in connection with circumstances that impact the Fair Market Value, if necessary;

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(g) determine whether Awards will be granted singly, in combination with, in tandem with, in replacement of, or as alternatives to, other Awards under this Plan or any other incentive or compensation plan of the Company or any Parent, Subsidiary or Affiliate;

(h) grant waivers of Plan or Award conditions;

(i) determine the vesting, exercisability and payment of Awards;

(j) correct any defect, supply any omission or reconcile any inconsistency in this Plan, any Award or any Award Agreement;

(k) determine whether an Award has been vested and/or earned;

(l) determine the terms and conditions of any, and to institute any Exchange Program;

(m) reduce or waive any criteria with respect to Performance Factors;

(n) adjust Performance Factors;

(o) adopt terms and conditions, rules and/or procedures (including the adoption of any subplan under this Plan) relating to the operation and administration of the Plan to accommodate requirements of local law and procedures outside of the United States or to qualify Awards for special tax treatment under laws of jurisdictions other than the United States;

(p) exercise discretion with respect to Performance Awards;

(q) make all other determinations necessary or advisable for the administration of this Plan; and

(r) delegate any of the foregoing to a subcommittee or to one or more executive officers pursuant to a specific delegation as permitted by applicable law, including Section 157(c) of the Delaware General Corporation Law.

4.2. Committee Interpretation and Discretion. Any determination made by the Committee with respect to any Award will be made in its sole discretion at the time of grant of the Award or, unless in contravention of any express term of the Plan or Award, at any later time, and such determination will be final and binding on the Company and all persons having an interest in any Award under the Plan. Any dispute regarding the interpretation of the Plan or any Award Agreement will be submitted by the Participant or Company to the Committee for review. The resolution of such a dispute by the Committee will be final and binding on the Company and the Participant. The Committee may delegate to one or more executive officers the authority to review and resolve disputes with respect to Awards held by Participants who are not Insiders, and such resolution will be final and binding on the Company and the Participant.

4.3. Section 16 of the Exchange Act. Awards granted to Participants who are subject to Section 16 of the Exchange Act must be approved by two or more “non-employee directors” (as defined in the regulations promulgated under Section 16 of the Exchange Act).

4.4. Documentation. The Award Agreement for a given Award, the Plan and any other documents may be delivered to, and accepted by, a Participant or any other person in any manner (including electronic distribution or posting) that meets applicable legal requirements.

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4.5. Foreign Award Recipients. Notwithstanding any provision of the Plan to the contrary, in order to comply with the laws and practices in other countries in which the Company and its Subsidiaries or Affiliates operate or have Employees or other individuals eligible for Awards, the Committee, in its sole discretion, will have the power and authority to: (a) determine which Subsidiaries and Affiliates will be covered by the Plan; (b) determine which individuals outside the United States are eligible to participate in the Plan; (c) modify the terms and conditions of any Award granted to individuals outside the United States or foreign nationals to comply with applicable foreign laws, policies, customs and practices; (d) establish subplans and modify exercise procedures and other terms and procedures, to the extent the Committee determines such actions to be necessary or advisable (and such subplans and/or modifications will be attached to this Plan as appendices, if necessary); provided, however, that no such subplans and/or modifications will increase the share limitations contained in Section 2.1 hereof; and (e) take any action, before or after an Award is made, that the Committee determines to be necessary or advisable to obtain approval or comply with any local governmental regulatory exemptions or approvals. Notwithstanding the foregoing, the Committee may not take any actions hereunder, and no Awards will be granted, that would violate the Exchange Act or any other applicable United States securities law, the Code, or any other applicable United States governing statute or law.

5. OPTIONS. An Option is the right but not the obligation to purchase a Share, subject to certain conditions, if applicable. The Committee may grant Options to eligible Employees, Consultants and Directors and will determine whether such Options will be Incentive Stock Options within the meaning of the Code (“ISOs”) or Nonqualified Stock Options (“NSOs”), the number of Shares subject to the Option, the Exercise Price of the Option, the period during which the Option may vest and be exercised, and all other terms and conditions of the Option, subject to the following terms of this section.

5.1. Option Grant. Each Option granted under this Plan will identify the Option as an ISO or an NSO. An Option may be, but need not be, awarded upon satisfaction of such Performance Factors during any Performance Period as are set out in advance in the Participant’s individual Award Agreement. If the Option is being earned upon the satisfaction of Performance Factors, then the Committee will: (a) determine the nature, length and starting date of any Performance Period for each Option; and (b) select from among the Performance Factors to be used to measure the performance, if any. Performance Periods may overlap and Participants may participate simultaneously with respect to Options that are subject to different performance goals and other criteria.

5.2. Date of Grant. The date of grant of an Option will be the date on which the Committee makes the determination to grant such Option, or a specified future date. The Award Agreement will be delivered to the Participant within a reasonable time after the granting of the Option.

5.3. Exercise Period. Options may be vested and exercisable within the times or upon the conditions as set forth in the Award Agreement governing such Option; provided, however, that no Option will be exercisable after the expiration of ten (10) years from the date the Option is granted; and provided further that no ISO granted to a person who, at the time the ISO is granted, directly or by attribution owns more than ten percent (10%) of the total combined voting power of all classes of stock of the Company or of any Parent or Subsidiary (“Ten Percent Stockholder”) will be exercisable after the expiration of five (5) years from the date the ISO is granted. The Committee also may provide for Options to become exercisable at one time or from time to time, periodically or otherwise, in such number of Shares or percentage of Shares as the Committee determines.

5.4. Exercise Price. The Exercise Price of an Option will be determined by the Committee when the Option is granted; provided that: (a) the Exercise Price of an Option will be not less than one hundred percent (100%) of the Fair Market Value of the Shares on the date of grant and (b) the Exercise Price of any ISO granted to a Ten Percent Stockholder will not be less than one hundred ten percent (110%) of the Fair Market Value of the Shares on the date of grant. Payment for the Shares purchased may be made in accordance with Section 11 and the Award Agreement and in accordance with any procedures established by the Company.

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5.5. Method of Exercise. Any Option granted hereunder will be vested and exercisable according to the terms of the Plan and at such times and under such conditions as determined by the Committee and set forth in the Award Agreement. An Option may not be exercised for a fraction of a Share. An Option will be deemed exercised when the Company receives: (a) notice of exercise (in such form as the Committee may specify from time to time) from the person entitled to exercise the Option (and/or via electronic execution through the authorized third party administrator), and (b) full payment for the Shares with respect to which the Option is exercised (together with applicable withholding taxes). Full payment may consist of any consideration and method of payment authorized by the Committee and permitted by the Award Agreement and the Plan. Shares issued upon exercise of an Option will be issued in the name of the Participant. Until the Shares are issued (as evidenced by the appropriate entry on the books of the Company or of a duly authorized transfer agent of the Company), no right to vote or receive dividends or any other rights as a stockholder will exist with respect to the Shares, notwithstanding the exercise of the Option. The Company will issue (or cause to be issued) such Shares promptly after the Option is exercised. No adjustment will be made for a dividend or other right for which the record date is prior to the date the Shares are issued, except as provided in Section 2.6 of the Plan. Exercising an Option in any manner will decrease the number of Shares thereafter available, both for purposes of the Plan and for sale under the Option, by the number of Shares as to which the Option is exercised.

5.6. Termination of Service. If the Participant’s Service terminates for any reason except for Cause or the Participant’s death or Disability, then the Participant may exercise such Participant’s Options only to the extent that such Options would have been exercisable by the Participant date Participant’s Service terminates no later than three (3) months after the date Participant’s Service terminates (or such shorter or longer time period as may be determined by the Committee, with any exercise beyond three (3) months after the date Participant’s employment terminates deemed to be the exercise of an NSO), but in any event no later than the expiration date of the Options.

(a) Death. If the Participant’s Service terminates because of the Participant’s death (or the Participant dies within three (3) months after Participant’s Service terminates other than for Cause or because of the Participant’s Disability), then the Participant’s Options may be exercised only to the extent that such Options would have been exercisable by the Participant on the date Participant’s Service terminates and must be exercised by the Participant’s legal representative, or authorized assignee, no later than twelve (12) months after the date Participant’s Service terminates (or such shorter time period or longer time period as may be determined by the Committee), but in any event no later than the expiration date of the Options.

(b) Disability. If the Participant’s Service terminates because of the Participant’s Disability, then the Participant’s Options may be exercised only to the extent that such Options would have been exercisable by the Participant on the date Participant’s Service terminates and must be exercised by the Participant (or the Participant’s legal representative or authorized assignee) no later than twelve (12) months after the date Participant’s Service terminates (or such shorter or longer time period as may be determined by the Committee, with any exercise beyond (a) three (3) months after the date Participant’s employment terminates when the termination of Service is for a Disability that is not a “permanent and total disability” as defined in Section 22(e)(3) of the Code, or (b) twelve (12) months after the date Participant’s employment terminates when the termination of Service is for a Disability that is a “permanent and total disability” as defined in Section 22(e)(3) of the Code, deemed to be exercise of an NSO), but in any event no later than the expiration date of the Options.

(c) Cause. If the Participant’s Service terminates for Cause, then Participant’s Options will expire on such Participant’s date of termination of Service, or at such later time and on such conditions as are determined by the Committee, but in any event no later than the expiration date of the Options. Unless otherwise provided in an employment agreement, Award Agreement or other applicable agreement Cause will have the meaning set forth in the Plan.

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5.7. Limitations on Exercise. The Committee may specify a minimum number of Shares that may be purchased on any exercise of an Option, provided that such minimum number will not prevent any Participant from exercising the Option for the full number of Shares for which it is then exercisable.

5.8. Limitations on ISOs. With respect to Awards granted as ISOs, to the extent that the aggregate Fair Market Value of the Shares with respect to which such ISOs are exercisable for the first time by the Participant during any calendar year (under all plans of the Company and any Parent or Subsidiary) exceeds one hundred thousand dollars ($100,000), such Options will be treated as NSOs. For purposes of this Section 5.8, ISOs will be taken into account in the order in which they were granted. The Fair Market Value of the Shares will be determined as of the time the Option with respect to such Shares is granted. In the event that the Code or the regulations promulgated thereunder are amended after the Effective Date to provide for a different limit on the Fair Market Value of Shares permitted to be subject to ISOs, such different limit will be automatically incorporated herein and will apply to any Options granted after the effective date of such amendment.

5.9. Modification, Extension or Renewal. The Committee may modify, extend or renew outstanding Options and authorize the grant of new Options in substitution therefor, provided that any such action may not, without the written consent of a Participant, impair any of such Participant’s rights under any Option previously granted. Any outstanding ISO that is modified, extended, renewed or otherwise altered will be treated in accordance with Section 424(h) of the Code. Subject to Section 18 of this Plan, by written notice to affected Participants, the Committee may reduce the Exercise Price of outstanding Options without the consent of such Participants; provided, however, that the Exercise Price may not be reduced below the Fair Market Value on the date the action is taken to reduce the Exercise Price.

5.10. No Disqualification. Notwithstanding any other provision in this Plan, no term of this Plan relating to ISOs will be interpreted, amended or altered, nor will any discretion or authority granted under this Plan be exercised, so as to disqualify this Plan under Section 422 of the Code or, without the consent of the Participant affected, to disqualify any ISO under Section 422 of the Code.

6. RESTRICTED STOCK AWARDS. A Restricted Stock Award is an offer by the Company to sell to an eligible Employee, Consultant, or Director Shares that are subject to restrictions (“Restricted Stock”). The Committee will determine to whom an offer will be made, the number of Shares the Participant may purchase, the Purchase Price, the restrictions under which the Shares will be subject and all other terms and conditions of the Restricted Stock Award, subject to the Plan.

6.1. Restricted Stock Purchase Agreement. All purchases under a Restricted Stock Award will be evidenced by an Award Agreement. Except as may otherwise be provided in an Award Agreement, a Participant accepts a Restricted Stock Award by signing and delivering to the Company an Award Agreement with full payment of the Purchase Price, within thirty (30) days from the date the Award Agreement was delivered to the Participant. If the Participant does not accept such Award within thirty (30) days, then the offer of such Restricted Stock Award will terminate, unless the Committee determines otherwise.

6.2. Purchase Price. The Purchase Price for a Restricted Stock Award will be determined by the Committee and may be less than Fair Market Value on the date the Restricted Stock Award is granted. Payment of the Purchase Price must be made in accordance with Section 11 of the Plan, and the Award Agreement and in accordance with any procedures established by the Company.

6.3. Terms of Restricted Stock Awards. Restricted Stock Awards will be subject to such restrictions as the Committee may impose or are required by law. These restrictions may be based on completion of a specified number of years of service with the Company or upon completion of Performance Factors, if any, during any Performance Period as set out in advance in the Participant’s Award Agreement. Prior to the grant of a Restricted Stock

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Award, the Committee shall: (a) determine the nature, length and starting date of any Performance Period for the Restricted Stock Award; (b) select from among the Performance Factors to be used to measure performance goals, if any; and (c) determine the number of Shares that may be awarded to the Participant. Performance Periods may overlap and a Participant may participate simultaneously with respect to Restricted Stock Awards that are subject to different Performance Periods and having different performance goals and other criteria.

6.4. Termination of Service. Except as may be set forth in the Participant’s Award Agreement, vesting ceases on such date Participant’s Service terminates (unless determined otherwise by the Committee).

7. STOCK BONUS AWARDS. A Stock Bonus Award is an award to an eligible Employee, Consultant, or Director of Shares for Services to be rendered or for past Services already rendered to the Company or any Parent, Subsidiary or Affiliate. All Stock Bonus Awards shall be made pursuant to an Award Agreement. No payment from the Participant will be required for Shares awarded pursuant to a Stock Bonus Award.

7.1. Terms of Stock Bonus Awards. The Committee will determine the number of Shares to be awarded to the Participant under a Stock Bonus Award and any restrictions thereon. These restrictions may be based upon completion of a specified number of years of service with the Company or upon satisfaction of performance goals based on Performance Factors during any Performance Period as set out in advance in the Participant’s Stock Bonus Agreement. Prior to the grant of any Stock Bonus Award the Committee shall: (a) determine the nature, length and starting date of any Performance Period for the Stock Bonus Award; (b) select from among the Performance Factors to be used to measure performance goals; and (c) determine the number of Shares that may be awarded to the Participant. Performance Periods may overlap and a Participant may participate simultaneously with respect to Stock Bonus Awards that are subject to different Performance Periods and different performance goals and other criteria.

7.2. Form of Payment to Participant. Payment may be made in the form of cash, whole Shares, or a combination thereof, based on the Fair Market Value of the Shares earned under a Stock Bonus Award on the date of payment, as determined in the sole discretion of the Committee.

7.3. Termination of Service. Except as may be set forth in the Participant’s Award Agreement, vesting ceases on such date Participant’s Service terminates (unless determined otherwise by the Committee).

8. STOCK APPRECIATION RIGHTS. A Stock Appreciation Right (“SAR”) is an award to an eligible Employee, Consultant, or Director that may be settled in cash, or Shares (which may consist of Restricted Stock), having a value equal to (a) the difference between the Fair Market Value on the date of exercise over the Exercise Price multiplied by (b) the number of Shares with respect to which the SAR is being settled (subject to any maximum number of Shares that may be issuable as specified in an Award Agreement). All SARs shall be made pursuant to an Award Agreement.

8.1. Terms of SARs. The Committee will determine the terms of each SAR including, without limitation: (a) the number of Shares subject to the SAR; (b) the Exercise Price and the time or times during which the SAR may be settled; (c) the consideration to be distributed on settlement of the SAR; and (d) the effect of the Participant’s termination of Service on each SAR. The Exercise Price of the SAR will be determined by the Committee when the SAR is granted, and may not be less than Fair Market Value. A SAR may be awarded upon satisfaction of Performance Factors, if any, during any Performance Period as are set out in advance in the Participant’s individual Award Agreement. If the SAR is being earned upon the satisfaction of Performance Factors, then the Committee will: (x) determine the nature, length and starting date of any Performance Period for each SAR; and (y) select from among the Performance Factors to be used to measure the performance, if any. Performance Periods may

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overlap and Participants may participate simultaneously with respect to SARs that are subject to different Performance Factors and other criteria.

8.2. Exercise Period and Expiration Date. A SAR will be exercisable within the times or upon the occurrence of events determined by the Committee and set forth in the Award Agreement governing such SAR. The SAR Agreement shall set forth the expiration date; provided that no SAR will be exercisable after the expiration of ten (10) years from the date the SAR is granted. The Committee may also provide for SARs to become exercisable at one time or from time to time, periodically or otherwise (including, without limitation, upon the attainment during a Performance Period of performance goals based on Performance Factors), in such number of Shares or percentage of the Shares subject to the SAR as the Committee determines. Except as may be set forth in the Participant’s Award Agreement, vesting ceases on the date Participant’s Service terminates (unless determined otherwise by the Committee). Notwithstanding the foregoing, the rules of Section 5.6 also will apply to SARs.

8.3. Form of Settlement. Upon exercise of a SAR, a Participant will be entitled to receive payment from the Company in an amount determined by multiplying (a) the difference between the Fair Market Value of a Share on the date of exercise over the Exercise Price; times (b) the number of Shares with respect to which the SAR is exercised. At the discretion of the Committee, the payment from the Company for the SAR exercise may be in cash, in Shares of equivalent value, or in some combination thereof. The portion of a SAR being settled may be paid currently or on a deferred basis with such interest, if any, as the Committee determines, provided that the terms of the SAR and any deferral satisfy the requirements of Section 409A of the Code to the extent applicable.

8.4. Termination of Service. Except as may be set forth in the Participant’s Award Agreement, vesting ceases on such date Participant’s Service terminates (unless determined otherwise by the Committee).

9. RESTRICTED STOCK UNITS. A Restricted Stock Unit (“RSU”) is an award to an eligible Employee, Consultant, or Director covering a number of Shares that may be settled in cash, or by issuance of those Shares (which may consist of Restricted Stock). All RSUs shall be made pursuant to an Award Agreement.

9.1. Terms of RSUs. The Committee will determine the terms of an RSU including, without limitation: (a) the number of Shares subject to the RSU; (b) the time or times during which the RSU may be settled; (c) the consideration to be distributed on settlement; and (d) the effect of the Participant’s termination of Service on each RSU; provided that no RSU shall have a term longer than ten (10) years. An RSU may be awarded upon satisfaction of such performance goals based on Performance Factors during any Performance Period as are set out in advance in the Participant’s Award Agreement. If the RSU is being earned upon satisfaction of Performance Factors, then the Committee will: (x) determine the nature, length and starting date of any Performance Period for the RSU; (y) select from among the Performance Factors to be used to measure the performance, if any; and (z) determine the number of Shares deemed subject to the RSU. Performance Periods may overlap and Participants may participate simultaneously with respect to RSUs that are subject to different Performance Periods and different performance goals and other criteria.

9.2. Form and Timing of Settlement. Payment of earned RSUs shall be made as soon as practicable after the date(s) determined by the Committee and set forth in the Award Agreement. The Committee, in its sole discretion, may settle earned RSUs in cash, Shares, or a combination of both. The Committee may also permit a Participant to defer payment under a RSU to a date or dates after the RSU is earned provided that the terms of the RSU and any deferral satisfy the requirements of Section 409A of the Code to the extent applicable.

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9.3. Termination of Service. Except as may be set forth in the Participant’s Award Agreement, vesting ceases on such date Participant’s Service terminates (unless determined otherwise by the Committee).

10. PERFORMANCE AWARDS. A Performance Award is an award to an eligible Employee, Consultant, or Director of the Company or any Parent, Subsidiary or Affiliate that is based upon the attainment of performance goals, as established by the Committee, and other terms and conditions specified by the Committee, and may be settled in cash, Shares (which may consist of, without limitation, Restricted Stock), other property, or any combination thereof. Grants of Performance Awards shall be made pursuant to an Award Agreement.

10.1. Performance Awards shall include Performance Shares, Performance Units, and cash-based Awards as set forth in Sections 10.1(a), 10.1(b), and 10.1(c) below.

(a) Performance Shares. The Committee may grant Awards of Performance Shares, designate the Participants to whom Performance Shares are to be awarded and determine the number of Performance Shares and the terms and conditions of each such Award.

(b) Performance Units. The Committee may grant Awards of Performance Units, designate the Participants to whom Performance Units are to be awarded and determine the number of Performance Units and the terms and conditions of each such Award.

(c) Cash-Settled Performance Awards. The Committee may grant cash-settled Performance Awards to Participants under the terms of this Plan.

The amount to be paid under any Performance Award may be adjusted on the basis of such further consideration as the Committee shall determine in its sole discretion.

10.2. Terms of Performance Awards. Performance Awards will be based on the attainment of performance goals using the Performance Factors within this Plan that are established by the Committee for the relevant Performance Period. The Committee will determine, and each Award Agreement shall set forth, the terms of each Performance Award including, without limitation: (a) the amount of any cash bonus, (b) the number of Shares deemed subject to an award of Performance Shares; (c) the Performance Factors and Performance Period that shall determine the time and extent to which each award of Performance Shares shall be settled; (d) the consideration to be distributed on settlement, and (e) the effect of the Participant’s termination of Service on each Performance Award. In establishing Performance Factors and the Performance Period the Committee will: (x) determine the nature, length and starting date of any Performance Period; (y) select from among the Performance Factors to be used; and (z) determine the number of Shares deemed subject to the award of Performance Shares. Prior to settlement the Committee shall determine the extent to which Performance Awards have been earned. Performance Periods may overlap and Participants may participate simultaneously with respect to Performance Awards that are subject to different Performance Periods and different performance goals and other criteria.

10.3. Termination of Service. Except as may be set forth in the Participant’s Award Agreement, vesting ceases on the date Participant’s Service terminates (unless determined otherwise by the Committee).

11. PAYMENT FOR SHARE PURCHASES. Payment from a Participant for Shares purchased pursuant to this Plan may be made in cash or by check or, where approved for the Participant by the Committee and where permitted by law (and to the extent not otherwise set forth in the applicable Award Agreement):

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(a) by cancellation of indebtedness of the Company to the Participant;

(b) by surrender of Shares by the Participant that have a Fair Market Value on the date of surrender equal to the aggregate exercise price of the Shares as to which said Award will be exercised or settled;

(c) by waiver of compensation due or accrued to the Participant for services rendered or to be rendered to the Company or a Parent or Subsidiary;

(d) by consideration received by the Company pursuant to a broker-assisted or other form of cashless exercise program implemented by the Company in connection with the Plan;

(e) by any combination of the foregoing; or

(f) by any other method of payment as is permitted by applicable law.

12. GRANTS TO NON-EMPLOYEE DIRECTORS.

12.1. No Non-Employee Director may receive Awards under the Plan that, when combined with cash compensation received for service as a Non-Employee Director, exceed $500,000.00 in value (as described below) in a calendar year, increased to $1,000,000.00 in value (as described below) in the calendar year of his or her initial services as a Non-Employee Director. Grant date fair value for purposes of Awards to Non-Employee Directors under the Plan will be determined as follows: (a) for Options and SARs, grant date fair value will be calculated using the Black-Scholes valuation methodology on the date of grant of such Option or SAR and (b) for all other Awards other than Options and SARs, grant date fair value will be determined by either (i) calculating the product of the Fair Market Value per Share on the date of grant and the aggregate number of Shares subject to the Award or (ii) calculating the product using an average of the Fair Market Value over a number of trading days and the aggregate number of Shares subject to the Award as determined by the Committee. Awards granted to an individual while he or she was serving in the capacity as an Employee or while he or she was a Consultant but not a Non-Employee Director will not count for purposes of the limitations set forth in this Section 12.1.

12.2. Grant and Eligibility. Awards pursuant to this Section 12 will be granted only to Non-Employee Directors, and may be automatically made pursuant to a policy adopted by the Board, or made from time to time as determined in the discretion of the Board. A Non-Employee Director who is elected or re-elected as a member of the Board will be eligible to receive an Award under this Section 12.

12.3. Vesting, Exercisability and Settlement. Except as set forth in Section 21, Awards will vest, become exercisable and be settled as determined by the Board. With respect to Options and SARs, the exercise price granted to Non-Employee Directors will not be less than the Fair Market Value of the Shares at the time that such Option or SAR is granted.

12.4. Election to Receive Awards in Lieu of Cash. A Non-Employee Director may elect to receive his or her annual retainer payments and/or meeting fees from the Company in the form of cash or Awards or a combination thereof, if permitted, and as determined, by the Committee. Such Awards shall be issued under the Plan. An election under this Section 12.4 shall be filed with the Company on the form prescribed by the Company.

13. WITHHOLDING TAXES.

13.1. Withholding Generally. Whenever Shares are to be issued in satisfaction of Awards granted under this Plan or a tax event occurs, the Company may require the Participant to remit to the Company, or to the Parent, Subsidiary or Affiliate, as applicable, employing the Participant, an amount sufficient to satisfy applicable U.S. federal, state, local and international tax or any other tax or social

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insurance liability (the “Tax-Related Items”) required to be withheld from the Participant prior to the delivery of Shares pursuant to exercise or settlement of any Award. Whenever payments in satisfaction of Awards granted under this Plan are to be made in cash, such payment will be net of an amount sufficient to satisfy applicable withholding obligations for Tax-Related Items. Unless otherwise determined by the Committee, the Fair Market Value of the Shares will be determined as of the date that the taxes are required to be withheld and such Shares will be valued based on the value of the actual trade or, if there is none, the Fair Market Value of the Shares as of the previous trading day.

13.2. Stock Withholding. The Committee, or its delegate(s), as permitted by applicable law, in its sole discretion and pursuant to such procedures as it may specify from time to time and to limitations of local law, may require or permit a Participant to satisfy such Tax Related Items legally due from the Participant, in whole or in part by (without limitation) (a) paying cash, (b) having the Company withhold otherwise deliverable cash or Shares having a Fair Market Value equal to the Tax-Related Items to be withheld, (c) delivering to the Company already-owned shares having a Fair Market Value equal to the Tax-Related Items to be withheld or (d) withholding from the proceeds of the sale of otherwise deliverable Shares acquired pursuant to an Award either through a voluntary sale or through a mandatory sale arranged by the Company. The Company may withhold or account for these Tax-Related Items by considering applicable statutory withholding rates or other applicable withholding rates, including up to (but not in excess of) the maximum permissible statutory tax rate for the applicable tax jurisdiction, to the extent consistent with applicable laws.

14. TRANSFERABILITY. Unless determined otherwise by the Committee or pursuant to Section 14.2, an Award may not be sold, pledged, assigned, hypothecated, transferred, or disposed of in any manner other than by will or by the laws of descent or distribution. If the Committee makes an Award transferable, including, without limitation, by instrument to an inter vivos or testamentary trust in which the Awards are to be passed to beneficiaries upon the death of the trustor (settlor) or by gift or by domestic relations order to a Permitted Transferee, such Award will contain such additional terms and conditions as the Committee deems appropriate. All Awards will be exercisable: (a) during the Participant’s lifetime only by the Participant, or the Participant’s guardian or legal representative; (b) after the Participant’s death, by the legal representative of the Participant’s heirs or legatees; and (c) in the case of all awards except ISOs, by a Permitted Transferee.

15. PRIVILEGES OF STOCK OWNERSHIP; RESTRICTIONS ON SHARES.

15.1. Voting and Dividends. No Participant will have any of the rights of a stockholder with respect to any Shares until the Shares are issued to the Participant, except for any dividend equivalent rights permitted by an applicable Award Agreement (“Dividend Equivalent Rights”). After Shares are issued to the Participant, the Participant will be a stockholder and have all the rights of a stockholder with respect to such Shares, including the right to vote and receive all dividends or other distributions made or paid with respect to such Shares; provided, that if such Shares are Restricted Stock, then any new, additional or different securities the Participant may become entitled to receive with respect to such Shares by virtue of a stock dividend, stock split or any other change in the corporate or capital structure of the Company will be subject to the same restrictions as the Restricted Stock; provided, further, that the Participant will have no right to such stock dividends or stock distributions with respect to Unvested Shares, and any such dividends or stock distributions will be accrued and paid only at such time, if any, as such Unvested Shares become vested Shares. The Committee, in its discretion, may provide in the Award Agreement evidencing any Award that the Participant will be entitled to Dividend Equivalent Rights with respect to the payment of cash dividends on Shares underlying an Award during the period beginning on the date the Award is granted and ending, with respect to each Share subject to the Award, on the earlier of the date on which the Award is exercised or settled or the date on which it is forfeited provided, that no Dividend Equivalent Right will be paid with respect to the Unvested Shares, and such dividends or stock distributions will be accrued and paid only at such time, if any, as such Unvested Shares become vested Shares. Such Dividend Equivalent Rights, if any, will be credited to the Participant in the form of additional whole Shares as of the date of payment of such cash dividends on Shares.

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15.2. Restrictions on Shares. At the discretion of the Committee, the Company may reserve to itself and/or its assignee(s) a right to repurchase (a “Right of Repurchase”) a portion of any or all Unvested Shares held by a Participant following such Participant’s termination of Service at any time within ninety (90) days (or such longer or shorter time determined by the Committee) after the later of the date Participant’s Service terminates and the date the Participant purchases Shares under this Plan, for cash and/or cancellation of purchase money indebtedness, at the Participant’s Purchase Price or Exercise Price, as the case may be.

16. CERTIFICATES. All Shares or other securities whether or not certificated, delivered under this Plan will be subject to such stock transfer orders, legends and other restrictions as the Committee may deem necessary or advisable, including restrictions under any applicable U.S. federal, state or foreign securities law, or any rules, regulations and other requirements of the SEC or any stock exchange or automated quotation system upon which the Shares may be listed or quoted and any non-U.S. exchange controls or securities law restrictions to which the Shares are subject.

17. ESCROW; PLEDGE OF SHARES. To enforce any restrictions on a Participant’s Shares, the Committee may require the Participant to deposit all certificates representing Shares, together with stock powers or other instruments of transfer approved by the Committee, appropriately endorsed in blank, with the Company or an agent designated by the Company to hold in escrow until such restrictions have lapsed or terminated, and the Committee may cause a legend or legends referencing such restrictions to be placed on the certificates. Any Participant who is permitted to execute a promissory note as partial or full consideration for the purchase of Shares under this Plan will be required to pledge and deposit with the Company all or part of the Shares so purchased as collateral to secure the payment of the Participant’s obligation to the Company under the promissory note; provided, however, that the Committee may require or accept other or additional forms of collateral to secure the payment of such obligation and, in any event, the Company will have full recourse against the Participant under the promissory note notwithstanding any pledge of the Participant’s Shares or other collateral. In connection with any pledge of the Shares, the Participant will be required to execute and deliver a written pledge agreement in such form as the Committee will from time to time approve. The Shares purchased with the promissory note may be released from the pledge on a pro rata basis as the promissory note is paid.

18. REPRICING; EXCHANGE AND BUYOUT OF AWARDS. Without prior stockholder approval, the Committee may (a) reprice Options or SARs (and where such repricing is a reduction in the Exercise Price of outstanding Options or SARs, the consent of the affected Participants is not required provided written notice is provided to them, notwithstanding any adverse tax consequences to them arising from the repricing), and (b) with the consent of the respective Participants (unless not required pursuant to Section 5.9 of the Plan), pay cash or issue new Awards in exchange for the surrender and cancellation of any, or all, outstanding Awards.

19. SECURITIES LAW AND OTHER REGULATORY COMPLIANCE. An Award will not be effective unless such Award is in compliance with all applicable U.S. and foreign federal and state securities and exchange control laws, rules and regulations of any governmental body, and the requirements of any stock exchange or automated quotation system upon which the Shares may then be listed or quoted, as they are in effect on the date of grant of the Award and also on the date of exercise or other issuance. Notwithstanding any other provision in this Plan, the Company will have no obligation to issue or deliver certificates for Shares under this Plan prior to: (a) obtaining any approvals from governmental agencies that the Company determines are necessary or advisable; and/or (b) completion of any registration or other qualification of such Shares under any state or federal or foreign law or ruling of any governmental body that the Company determines to be necessary or advisable. The Company will be under no obligation to register the Shares with the SEC or to effect compliance with the registration, qualification or listing requirements of any foreign or state securities laws, exchange control laws, stock exchange or automated quotation system, and the Company will have no liability for any inability or failure to do so.

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20. NO OBLIGATION TO EMPLOY. Nothing in this Plan or any Award granted under this Plan will confer or be deemed to confer on any Participant any right to continue in the employ of, or to continue any other relationship with, the Company or any Parent, Subsidiary or Affiliate or limit in any way the right of the Company or any Parent, Subsidiary or Affiliate to terminate Participant’s employment or other relationship at any time.

21. CORPORATE TRANSACTIONS.

21.1. Assumption or Replacement of Awards by Successor. In the event that the Company is subject to a Corporate Transaction, outstanding Awards acquired under the Plan shall be subject to the agreement evidencing the Corporate Transaction, which need not treat all outstanding Awards in an identical manner. Such agreement, without the Participant’s consent, shall provide for one or more of the following with respect to all outstanding Awards as of the effective date of such Corporate Transaction:

(a) The continuation of an outstanding Award by the Company (if the Company is the successor entity).

(b) The assumption of an outstanding Award by the successor or acquiring entity (if any) of such Corporate Transaction (or by its parents, if any), which assumption, will be binding on all selected Participants; provided that the exercise price and the number and nature of shares issuable upon exercise of any such option or stock appreciation right, or any award that is subject to Section 409A of the Code, will be adjusted appropriately pursuant to Section 424(a) of the Code and/or Section 409A of the Code, as applicable. The Board shall have full power and authority to assign the Company’s right to repurchase or re-acquire or forfeiture rights to such successor or acquiring corporation.

(c) The substitution by the successor or acquiring entity in such Corporate Transaction (or by its parents, if any) of equivalent awards with substantially the same terms for such outstanding Awards (except that the exercise price and the number and nature of shares issuable upon exercise of any such option or stock appreciation right, or any award that is subject to Section 409A of the Code, will be adjusted appropriately pursuant to Section 424(a) of the Code and/or Section 409A of the Code, as applicable).

(d) The full or partial acceleration of exercisability or vesting and accelerated expiration of an outstanding Award and lapse of the Company’s right to repurchase or re-acquire shares acquired under an Award or lapse of forfeiture rights with respect to shares acquired under an Award.

(e) The settlement of the full value of such outstanding Award (whether or not then vested or exercisable) in cash, cash equivalents, or securities of the successor entity (or its parent, if any) with a Fair Market Value equal to the required amount, followed by the cancellation of such Awards; provided however, that such Award may be cancelled if such Award has no value, as determined by the Committee, in its discretion. Subject to Section 409A of the Code, such payment may be made in installments and may be deferred until the date or dates the Award would have become exercisable or vested. Such payment may be subject to vesting based on the Participant’s continued service, provided that the vesting schedule shall not be less favorable to the Participant than the schedule under which the Award would have become vested or exercisable. For purposes of this Section 21.1(e), the Fair Market Value of any security shall be determined without regard to any vesting conditions that may apply to such security.

In the event a successor or acquiring corporation refuses to assume, convert, replace or substitute Awards or it is otherwise determined that Awards shall not be so assumed, converted, replaced or substituted pursuant to this Section 21.1, each such Award shall become fully vested and, as applicable, exercisable (or deemed exercised if determined by the Committee in its sole discretion) immediately prior

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to the consummation of the Corporate Transaction and all forfeiture restrictions on any such Award shall lapse. If an Award vests and, as applicable, is exercisable in lieu of assumption or substitution in connection with a Corporate Transaction, the Committee will notify the Participant in writing or electronically of such vesting and that the Award will be exercisable for a period of time determined by the Committee in its sole discretion, and such Award will terminate upon the earlier of the expiration of such period or upon the Change in Control.

21.2. Assumption of Awards by the Company. The Company, from time to time, also may substitute or assume outstanding awards granted by another company, whether in connection with an acquisition of such other company or otherwise, by either; (a) granting an Award under this Plan in substitution of such other company’s award; or (b) assuming such award as if it had been granted under this Plan if the terms of such assumed award could be applied to an Award granted under this Plan. Such substitution or assumption will be permissible if the holder of the substituted or assumed award would have been eligible to be granted an Award under this Plan if the other company had applied the rules of this Plan to such grant. In the event the Company assumes an award granted by another company, the terms and conditions of such award will remain unchanged (except that the Purchase Price or the Exercise Price, as the case may be, and the number and nature of Shares issuable upon exercise or settlement of any such Award will be adjusted appropriately pursuant to Section 424(a) of the Code). In the event the Company elects to grant a new Option in substitution rather than assuming an existing option, such new Option may be granted with a similarly adjusted Exercise Price. Substitute Awards will not reduce the number of Shares authorized for grant under the Plan or authorized for grant to a Participant in a calendar year.

21.3. Non-Employee Directors’ Awards. Notwithstanding any provision to the contrary herein, in the event of a Corporate Transaction, the vesting of all Awards granted to Non-Employee Directors will accelerate and such Awards will become exercisable (as applicable) in full prior to the consummation of such event at such times and on such conditions as the Committee determines.

22. ADOPTION AND STOCKHOLDER APPROVAL. This Plan will be submitted for the approval of the Company’s stockholders, consistent with applicable laws, within twelve (12) months before or after the date this Plan is adopted by the Board.

23. TERM OF PLAN/GOVERNING LAW. Unless earlier terminated as provided herein, this Plan will become effective on the Effective Date and will terminate ten (10) years from the date this Plan is adopted by the Board. This Plan and all Awards granted hereunder will be governed by and construed in accordance with the laws of the State of Delaware (excluding its conflict of laws rules).

24. AMENDMENT OR TERMINATION OF PLAN. The Board may at any time terminate or amend this Plan in any respect, including, without limitation, amendment of any form of Award Agreement or instrument to be executed pursuant to this Plan; provided, however, that the Board will not, without the approval of the stockholders of the Company, amend this Plan in any manner that requires such stockholder approval; provided further, that a Participant’s Award will be governed by the version of this Plan then in effect at the time such Award was granted. No termination or amendment of the Plan or any outstanding Award may adversely affect any then outstanding Award without the consent of the Participant, unless such termination or amendment is necessary to comply with applicable law, regulation or rule.

25. NONEXCLUSIVITY OF THE PLAN. Neither the adoption of this Plan by the Board, the submission of this Plan to the stockholders of the Company for approval, nor any provision of this Plan will be construed as creating any limitations on the power of the Board to adopt such additional compensation arrangements as it may deem desirable, including, without limitation, the granting of stock awards and bonuses otherwise than under this Plan, and such arrangements may be either generally applicable or applicable only in specific cases.

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26. INSIDER TRADING POLICY. Each Participant who receives an Award will comply with any policy adopted by the Company from time to time covering transactions in the Company’s securities by Employees, officers and/or directors of the Company, as well as with any applicable insider trading or market abuse laws to which the Participant may be subject.

27. ALL AWARDS SUBJECT TO COMPANY CLAWBACK OR RECOUPMENT POLICY. All Awards, subject to applicable law, shall be subject to clawback or recoupment pursuant to any compensation clawback or recoupment policy adopted by the Board or required by law during the term of Participant’s employment or other service with the Company that is applicable to executive officers, employees, directors or other service providers of the Company, and in addition to any other remedies available under such policy and applicable law, may require the cancellation of outstanding Awards and the recoupment of any gains realized with respect to Awards.

28. DEFINITIONS. As used in this Plan, and except as elsewhere defined herein, the following terms will have the following meanings:

28.1. “Affiliate” means any person or entity that directly or indirectly through one or more intermediaries controls, or is controlled by, or is under common control with, the Company, including any general partner, managing member, officer or director of the Company, in each case as of the date on which, or at any time during the period for which, the determination of affiliation is being made. For purposes of this definition, the term “control” (including the correlative meanings of the terms “controlled by” and “under common control with”), as used with respect to any person or entity, means the possession, directly or indirectly, of the power to direct or cause the direction of the management policies of such person or entity, whether through the ownership of voting securities or by contract or otherwise.

28.2. “Award” means any award under the Plan, including any Option, Restricted Stock, Stock Bonus, Stock Appreciation Right, Restricted stock Unit or Performance Award.

28.3. “Award Agreement” means, with respect to each Award, the written or electronic agreement between the Company and the Participant setting forth the terms and conditions of the Award, and country-specific appendix thereto for grants to non-U.S. Participants, which will be in substantially a form (which need not be the same for each Participant) that the Committee (or in the case of Award agreements that are not used for Insiders, the Committee’s delegate(s)) has from time to time approved, and will comply with and be subject to the terms and conditions of this Plan.

28.4. “Board” means the Board of Directors of the Company.

28.5. “Cause” means (a) Participant’s willful failure substantially to perform his or her duties and responsibilities to the Company or deliberate violation of a Company policy; (b) Participant’s commission of any act of fraud, embezzlement, dishonesty or any other willful misconduct that has caused or is reasonably expected to result in material injury to the Company; (c) unauthorized use or disclosure by Participant of any proprietary information or trade secrets of the Company or any other party to whom the Participant owes an obligation of nondisclosure as a result of his or her relationship with the Company; or (d) Participant’s willful breach of any of his or her obligations under any written agreement or covenant with the Company. The determination as to whether a Participant is being terminated for Cause will be made by the Company and will be final and binding on the Participant. The foregoing definition does not in any way limit the Company’s ability to terminate a Participant’s employment or consulting relationship at any time as provided in Section 20 above, and the term “Company” will be interpreted to include any Subsidiary or Parent, as appropriate. Notwithstanding the foregoing, the foregoing definition of “Cause” may, in part or in whole, be modified or replaced in each individual employment agreement, Award Agreement or other applicable agreement with any Participant.

28.6. “Code” means the United States Internal Revenue Code of 1986, as amended, and the regulations promulgated thereunder.

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28.7. “Committee” means the Compensation Committee of the Board or those persons to whom administration of the Plan, or part of the Plan, has been delegated as permitted by law.

28.8. “Company” means Sutro Biopharma, Inc., a Delaware corporation, or any successor corporation.

28.9. “Consultant” means any natural person, including an advisor or independent contractor, engaged by the Company or a Parent, Subsidiary or Affiliate to render services to such entity.

28.10. “Corporate Transaction” means the occurrence of any of the following events: (a) any “Person” (as such term is used in Sections 13(d) and 14(d) of the Exchange Act) becomes the “beneficial owner” (as defined in Rule 13d-3 of the Exchange Act), directly or indirectly, of securities of the Company representing more than fifty percent (50%) of the total voting power represented by the Company’s then-outstanding voting securities; provided, however, that for purposes of this subclause (a) the acquisition of additional securities by any one Person who is considered to own more than fifty percent (50%) of the total voting power of the securities of the Company will not be considered a Corporate Transaction; (b) the consummation of the sale or disposition by the Company of all or substantially all of the Company’s assets; (c) the consummation of a merger or consolidation of the Company with any other corporation, other than a merger or consolidation which would result in the voting securities of the Company outstanding immediately prior thereto continuing to represent (either by remaining outstanding or by being converted into voting securities of the surviving entity or its parent) at least fifty percent (50%) of the total voting power represented by the voting securities of the Company or such surviving entity or its parent outstanding immediately after such merger or consolidation; (d) any other transaction which qualifies as a “corporate transaction” under Section 424(a) of the Code wherein the stockholders of the Company give up all of their equity interest in the Company (except for the acquisition, sale or transfer of all or substantially all of the outstanding shares of the Company) or (e) a change in the effective control of the Company that occurs on the date that a majority of members of the Board is replaced during any twelve (12) month period by members of the Board whose appointment or election is not endorsed by a majority of the members of the Board prior to the date of the appointment or election. For purpose of this subclause (e), if any Person is considered to be in effective control of the Company, the acquisition of additional control of the Company by the same Person will not be considered a Corporate Transaction. For purposes of this definition, Persons will be considered to be acting as a group if they are owners of a corporation that enters into a merger, consolidation, purchase or acquisition of stock, or similar business transaction with the Company. Notwithstanding the foregoing, to the extent that any amount constituting deferred compensation (as defined in Section 409A of the Code) would become payable under this Plan by reason of a Corporate Transaction, such amount will become payable only if the event constituting a Corporate Transaction would also qualify as a change in ownership or effective control of the Company or a change in the ownership of a substantial portion of the assets of the Company, each as defined within the meaning of Code Section 409A, as it has been and may be amended from time to time, and any proposed or final Treasury Regulations and IRS guidance that has been promulgated or may be promulgated thereunder from time to time.

28.11. “Director” means a member of the Board.

28.12. “Disability” means in the case of incentive stock options, total and permanent disability as defined in Section 22(e)(3) of the Code and in the case of other Awards, that the Participant is unable to engage in any substantial gainful activity by reason of any medically determinable physical or mental impairment that can be expected to result in death or can be expected to last for a continuous period of not less than 12 months.

28.13. “Dividend Equivalent Right” means the right of a Participant, granted at the discretion of the Committee or as otherwise provided by the Plan, to receive a credit for the account of such Participant in an amount equal to the cash, stock or other property dividends in amounts equivalent to cash, stock or other property dividends for each Share represented by an Award held by such Participant.

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28.14. “Effective Date” means the day immediately prior to the Company’s IPO Registration Date, subject to approval of the Plan by the Company’s stockholders.

28.15. “Employee” means any person, including Officers and Directors, providing services as an employee to the Company or any Parent, Subsidiary or Affiliate. Neither service as a Director nor payment of a director’s fee by the Company will be sufficient to constitute “employment” by the Company.

28.16. “Exchange Act” means the United States Securities Exchange Act of 1934, as amended.

28.17. “Exchange Program” means a program pursuant to which (a) outstanding Awards are surrendered, cancelled or exchanged for cash, the same type of Award or a different Award (or combination thereof) or (b) the exercise price of an outstanding Award is increased or reduced.

28.18. “Exercise Price” means, with respect to an Option, the price at which a holder may purchase the Shares issuable upon exercise of an Option and with respect to a SAR, the price at which the SAR is granted to the holder thereof.

28.19. “Fair Market Value” means, as of any date, the value of a share of the Company’s common stock determined as follows:

(a) if such common stock is publicly traded and is then listed on a national securities exchange, its closing price on the date of determination on the principal national securities exchange on which the common stock is listed or admitted to trading as reported in The Wall Street Journal or such other source as the Committee deems reliable;

(b) if such common stock is publicly traded but is neither listed nor admitted to trading on a national securities exchange, the average of the closing bid and asked prices on the date of determination as reported in The Wall Street Journal or such other source as the Committee deems reliable;

(c) in the case of an Option or SAR grant made on the IPO Registration Date, the price per share at which Shares are initially offered for sale to the public by the Company’s underwriters in the initial public offering of Shares as set forth in the Company’s final prospectus included within the registration statement on Form S-1 filed with the SEC under the Securities Act; or

(d) by the Board or the Committee in good faith.

28.20. “Insider” means an officer or director of the Company or any other person whose transactions in the Company’s common stock are subject to Section 16 of the Exchange Act.

28.21. “IPO Registration Date” means the date on which the Company’s registration statement on Form S-1 in connection with its initial public offering of common stock is declared effective by the SEC under the Securities Act.

28.22. “IRS” means the United States Internal Revenue Service.

28.23. “Non-Employee Director” means a Director who is not an Employee of the Company or any Parent or Subsidiary.

28.24. “Option” means an Award as defined in Section 5 and granted under the Plan.

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28.25. “Parent” means any corporation (other than the Company) in an unbroken chain of corporations ending with the Company if each of such corporations other than the Company owns stock possessing fifty percent (50%) or more of the total combined voting power of all classes of stock in one of the other corporations in such chain.

28.26. “Participant” means a person who holds an Award under this Plan.

28.27. “Performance Award” means an Award as defined in Section 10 and granted under the Plan.

28.28. “Performance Factors” means any of the factors selected by the Committee and specified in an Award Agreement, from among the following objective or subjective measures, either individually, alternatively or in any combination applied to the Participant, the Company, any business unit or Subsidiary, either individually, alternatively, or in any combination, on a GAAP or non-GAAP basis, and measured, to the extent applicable on an absolute basis or relative to a pre-established target, to determine whether the performance goals established by the Committee with respect to applicable Awards have been satisfied:

(a) Profit Before Tax;

(b) Sales;

(c) Expenses;

(d) Billings;

(e) Revenue;

(f) Net revenue;

(g) Earnings (which may include earnings before interest and taxes, earnings before taxes, net earnings, stock-based compensation expenses, depreciation and amortization);

(h) Operating income;

(i) Operating margin;

(j) Operating profit;

(k) Controllable operating profit, or net operating profit;

(l) Net Profit;

(m) Gross margin;

(n) Operating expenses or operating expenses as a percentage of revenue;

(o) Net income;

(p) Earnings per share;

(q) Total stockholder return;

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(r) Market share;

(s) Return on assets or net assets;

(t) The Company’s stock price;

(u) Growth in stockholder value relative to a pre-determined index;

(v) Return on equity;

(w) Return on invested capital;

(x) Cash Flow (including free cash flow or operating cash flows);

(y) Balance of cash, cash equivalents and marketable securities;

(z) Cash conversion cycle;

(aa) Economic value added;

(bb) Individual confidential business objectives;

(cc) Contract awards or backlog;

(dd) Overhead or other expense reduction;

(ee) Credit rating;

(ff) Completion of an identified special project;

(gg) Completion of a joint venture or other corporate transaction;

(hh) Strategic plan development and implementation;

(ii) Succession plan development and implementation;

(jj) Improvement in workforce diversity;

(kk) Employee satisfaction;

(ll) Employee retention;

(mm) Customer indicators and/or satisfaction;

(nn) New product invention or innovation;

(oo) Research and development expenses;

(pp) Attainment of research and development milestones;

(qq) Improvements in productivity;

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(rr) Bookings;

(ss) Working-capital targets and changes in working capital; Attainment of operating goals and employee metrics; and

(tt) Any other metric as determined by the Committee.

The Committee may provide for one or more equitable adjustments to the Performance Factors to preserve the Committee’s original intent regarding the Performance Factors at the time of the initial award grant, such as but not limited to, adjustments in recognition of unusual or non-recurring items such as acquisition related activities or changes in applicable accounting rules. It is within the sole discretion of the Committee to make or not make any such equitable adjustments.

28.29. “Performance Period” means one or more periods of time, which may be of varying and overlapping durations over which the attainment of one or more Performance Factors will be measured for the purpose of determining a Participant’s right to, and the payment of, a Performance Award.

28.30. “Performance Share” means an Award as defined in Section 10 and granted under the Plan.

28.31. “Permitted Transferee” means any child, stepchild, grandchild, parent, stepparent, grandparent, spouse, former spouse, sibling, niece, nephew, mother-in-law, father-in-law, son-in-law, daughter-in-law, brother-in-law, or sister-in-law (including adoptive relationships) of the Employee, any person sharing the Employee’s household (other than a tenant or employee), a trust in which these persons (or the Employee) have more than 50% of the beneficial interest, a foundation in which these persons (or the Employee) control the management of assets, and any other entity in which these persons (or the Employee) own more than 50% of the voting interests.

28.32. “Performance Unit” means an Award as defined in Section 10 and granted under the Plan.

28.33. “Plan” means this Sutro Biopharma, Inc. 2018 Equity Incentive Plan.

28.34. “Purchase Price” means the price to be paid for Shares acquired under the Plan, other than Shares acquired upon exercise of an Option or SAR.

28.35. “Restricted Stock Award” means an Award as defined in Section 6 and granted under the Plan (or issued pursuant to the early exercise of an Option).

28.36. “Restricted Stock Unit” means an Award as defined in Section 9 and granted under the Plan.

28.37. “SEC” means the United States Securities and Exchange Commission.

28.38. “Securities Act” means the United States Securities Act of 1933, as amended.

28.39. “Service” means service as an Employee, Consultant, Director or Non-Employee Director, to the Company or a Parent, Subsidiary or Affiliate, subject to such further limitations as may be set forth in the Plan or the applicable Award Agreement. An Employee will not be deemed to have ceased to provide Service in the case of (a) sick leave, (b) military leave, or (c) any other leave of absence approved by the Company; provided, that such leave is for a period of not more than 90 days unless reemployment upon the expiration of such leave is guaranteed by contract or statute. Notwithstanding anything to the contrary, an Employee will not be deemed to have ceased to provide Service if a formal

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policy adopted from time to time by the Company and issued and promulgated to employees in writing provides otherwise. In the case of any Employee on an approved leave of absence or a reduction in hours worked (for illustrative purposes only, a change in schedule from that of full-time to part-time), the Committee may make such provisions respecting suspension or modification of vesting of the Award while on leave from the employ of the Company or a Parent, Subsidiary or Affiliate or during such change in working hours as it may deem appropriate, except that in no event may an Award be exercised after the expiration of the term set forth in the applicable Award Agreement. In the event of military or other protected leave, if required by applicable laws, vesting will continue for the longest period that vesting continues under any other statutory or Company approved leave of absence and, upon a Participant’s returning from military leave, he or she will be given vesting credit with respect to Awards to the same extent as would have applied had the Participant continued to provide Service to the Company throughout the leave on the same terms as he or she was providing Service immediately prior to such leave. An Employee will have terminated employment as of the date he or she ceases to provide Service (regardless of whether the termination is in breach of local employment laws or is later found to be invalid) and employment will not be extended by any notice period or garden leave mandated by local law, provided however, a change in status from an Employee to a Consultant or a Non-Employee Director (or vice versa) will not terminate a Participant’s Service, unless determined by the Committee, in its discretion or to the extent set forth in the applicable Award Agreement. The Committee will have sole discretion to determine whether a Participant has ceased to provide Service and the effective date on which the Participant ceased to provide Service.

28.40. “Shares” means shares of the Company’s common stock, and the common stock of any successor entity.

28.41. “Stock Appreciation Right” means an Award as defined in Section 8 and granted under the Plan.

28.42. “Stock Bonus” means an Award granted pursuant to Section 7 of the Plan.

28.43. “Subsidiary” means any corporation (other than the Company) in an unbroken chain of corporations beginning with the Company if each of the corporations other than the last corporation in the unbroken chain owns stock possessing fifty percent (50%) or more of the total combined voting power of all classes of stock in one of the other corporations in such chain.

28.44. “Treasury Regulations” means regulations promulgated by the United States Treasury Department.

28.45. “Unvested Shares” means Shares that have not yet vested or are subject to a right of repurchase in favor of the Company (or any successor thereto).

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SUTRO BIOPHARMA, INC.

2018 EQUITY INCENTIVE PLAN

GLOBAL NOTICE OF STOCK OPTION GRANT

Unless otherwise defined herein, the terms defined in the Sutro Biopharma, Inc. (the “Company”) 2018 Equity Incentive Plan (the “Plan”) will have the same meanings in this Global Notice of Stock Option Grant and the electronic representation of this Global Notice of Stock Option Grant established and maintained by the Company or a third party designated by the Company (this “Notice”).

Name:

Address:

You (“Participant”) have been granted an option to purchase shares of common stock of the Company (the “Option”) under the Plan subject to the terms and conditions of the Plan, this Notice and the attached Global Stock Option Award Agreement (the “Option Agreement”), including any applicable country-specific provisions in the appendix attached hereto (the “Appendix”), which constitutes part of the Option Agreement.

Grant Number:

Date of Grant:

Vesting Commencement Date:

Exercise Price per Share:

Total Number of Shares:

Type of Option: | Non-Qualified Stock Option Incentive Stock Option

Expiration Date: | , 20 ; This Option expires earlier if Participant’s Service terminates earlier, as described in the Option Agreement.

Vesting Schedule: | Subject to the limitations set forth in this Notice, the Plan and the Option Agreement, the Option will vest in accordance with the following schedule: [insert applicable vesting schedule]

By accepting (whether in writing, electronically or otherwise) the Option, Participant acknowledges and agrees to the following:

| 1) | Participant understands that Participant’s employment or consulting relationship or Service with the Company or a Parent or Subsidiary or Affiliate is for an unspecified duration, can be terminated at any time (i.e., is “at-will”), except where otherwise prohibited by applicable law, and that nothing in this Notice, the Option Agreement or the Plan changes the nature of that relationship. Participant acknowledges that the vesting of the Option pursuant to this Notice is subject to Participant’s continuing Service as an Employee, Director or Consultant. Participant agrees and acknowledges that the Vesting Schedule may change prospectively in the event that Participant’s service status changes between full- and part-time and/or in the event Participant is on a leave of absence, in accordance with Company policies relating to work schedules and vesting of Awards or as determined by the Committee. Furthermore, the period during which Participant may exercise the Option after termination of Service, if any, will commence on the Termination Date (as defined in the Option Agreement).

| 2) | This grant is made under and governed by the Plan, the Option Agreement and this Notice, and this Notice is subject to the terms and conditions of the Option Agreement and the Plan, both of which are incorporated herein by reference. Participant has read the Notice, the Option Agreement and the Plan.

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| 3) | Participant has read the Company’s Insider Trading Policy, and agrees to comply with such policy, as it may be amended from time to time, whenever Participant acquires or disposes of the Company’s securities.

| 4) | By accepting the Option, Participant consents to electronic delivery and participation as set forth in the Option Agreement.

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SUTRO BIOPHARMA, INC.

2018 EQUITY INCENTIVE PLAN

GLOBAL STOCK OPTION AWARD AGREEMENT

Unless otherwise defined in this Global Stock Option Award Agreement (this “Option Agreement”), any capitalized terms used herein will have the meaning ascribed to them in the Sutro Biopharma, Inc. 2018 Equity Incentive Plan (the “Plan”).

Participant has been granted an option to purchase Shares (the “Option”) of Sutro Biopharma, Inc. (the “Company”), subject to the terms, restrictions and conditions of the Plan, the Global Notice of Stock Option Grant (the “Notice”) and this Option Agreement, including any applicable country-specific provisions in the appendix attached hereto (the “Appendix”), which constitutes part of this Option Agreement.

1. Vesting Rights. Subject to the applicable provisions of the Plan and this Option Agreement, this Option may be exercised, in whole or in part, in accordance with the Vesting Schedule set forth in the Notice. Participant acknowledges that the vesting of the Option pursuant to this Notice and Agreement is subject to Participant’s continuing Service as an Employee, Director or Consultant.

2. Grant of Option. Participant has been granted an Option for the number of Shares set forth in the Notice at the exercise price per Share in U.S. Dollars set forth in the Notice (the “Exercise Price”). In the event of a conflict between the terms and conditions of the Plan and the terms and conditions of this Option Agreement, the terms and conditions of the Plan shall prevail. If designated in the Notice as an Incentive Stock Option (“ISO”), this Option is intended to qualify as an Incentive Stock Option under Section 422 of the Code. However, if this Option is intended to be an ISO, to the extent that it exceeds the U.S. $100,000 rule of Code Section 422(d) it shall be treated as a Nonqualified Stock Option (“NSO”).

3. Termination Period.

(a) General Rule. If Participant’s Service terminates for any reason except death or Disability, and other than for Cause, then this Option will expire at the close of business at Company headquarters on the date three (3) months after Participant’s Termination Date (as defined below) (or such shorter time period not less than thirty (30) days or longer time period as may be determined by the Committee, with any exercise beyond three (3) months after the date Participant’s Service terminates deemed to be the exercise of an NSO). If Participant’s Service is terminated for Cause, this Option will expire upon the date of such termination. The Company determines when Participant’s Service terminates for all purposes under this Option Agreement.

(b) Death; Disability. If Participant dies before Participant’s Service terminates (or Participant dies within three months of Participant’s termination of Service other than for Cause), then this Option will expire at the close of business at Company headquarters on the date twelve (12) months after the date of death (or such shorter time period not less than six (6) months or longer time period as may be determined by the Committee or a shorter period set forth in the Appendix for a specific jurisdiction, subject to the expiration details in Section 7). If Participant’s Service terminates because of Participant’s Disability, then this Option will expire at the close of business at Company headquarters on the date twelve (12) months after Participant’s Termination Date (or such shorter time period not less than six (6) months or longer time period as may be determined by the Committee or a shorter period set forth in the Appendix for a specific jurisdiction, subject to the expiration details in Section 7).

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(c) No Notification of Exercise Periods. Participant is responsible for keeping track of these exercise periods following Participant’s termination of Service for any reason. The Company will not provide further notice of such periods. In no event shall this Option be exercised later than the Expiration Date set forth in the Notice.

(d) Termination. For purposes of this Option, Participant’s Service will be considered terminated (regardless of the reason for such termination and whether or not later found to be invalid or in breach of employment laws in the jurisdiction where Participant is employed or the terms of Participant’s employment agreement, if any) as of the date Participant is no longer actively providing services to the Company, its Parent or one of its Subsidiaries or Affiliates (i.e., Participant’s period of Service would not include any contractual notice period or any period of “garden leave” or similar period mandated under employment laws in the jurisdiction where Participant is employed or the terms of Participant’s employment agreement, if any) (the “Termination Date”). Unless otherwise provided in this Option Agreement or determined by the Company, Participant’s right to vest in the Option under the Plan, if any, will terminate as of the Termination Date and Participant’s right to exercise the Option after termination of Service, if any, will be measured from the Termination Date.

In case of any dispute as to whether and when a termination of Service has occurred, the Committee will have sole discretion to determine whether such termination of Service has occurred and the effective date of such termination (including whether Participant may still be considered to be actively providing Services while on a leave of absence).

If Participant does not exercise this Option within the termination period set forth in the Notice or the termination periods set forth above, the Option shall terminate in its entirety. In no event, may any Option be exercised after the Expiration Date of the Option as set forth in the Notice.

4. Exercise of Option.

(a) Right to Exercise. This Option is exercisable during its term in accordance with the Vesting Schedule set forth in the Notice and the applicable provisions of the Plan and this Option Agreement. In the event of Participant’s death, Disability, termination for Cause or other cessation of Service, the exercisability of the Option is governed by the applicable provisions of the Plan, the Notice and this Option Agreement. This Option may not be exercised for a fraction of a Share.

(b) Method of Exercise. This Option is exercisable by delivery of an exercise notice in a form specified by the Company (the “Exercise Notice”), which will state the election to exercise the Option, the number of Shares in respect of which the Option is being exercised (the “Exercised Shares”), and such other representations and agreements as may be required by the Company pursuant to the provisions of the Plan. The Exercise Notice will be delivered in person, by mail, via electronic mail or facsimile or by other authorized method to the Secretary of the Company or other person designated by the Company. The Exercise Notice will be accompanied by payment of the aggregate Exercise Price as to all Exercised Shares together with any applicable Tax-Related Items (as defined in Section 8 below). This Option will be deemed to be exercised upon receipt by the Company of such fully executed Exercise Notice accompanied by such aggregate Exercise Price and payment of any applicable Tax-Related Items (as defined below). No Shares will be issued pursuant to the exercise of this Option unless such issuance and exercise complies with all relevant provisions of law and the requirements of any stock exchange or quotation service upon which the Shares are then listed and any exchange control registrations. Assuming such compliance, for United States income tax purposes the Exercised Shares will be considered transferred to Participant on the date the Option is exercised with respect to such Exercised Shares.

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(c) Exercise by Another. If another person wants to exercise this Option after it has been transferred to him or her in compliance with this Option Agreement, that person must prove to the Company’s satisfaction that he or she is entitled to exercise this Option. That person must also complete the proper Exercise Notice form (as described above) and pay the Exercise Price (as described below) and any applicable Tax-Related Items (as described below).

5. Method of Payment. Payment of the aggregate Exercise Price, and any Tax-Related Items (as defined below) withholding, will be by any of the following, or a combination thereof, at the election of Participant:

(a) Participant’s personal check (representing readily available funds), wire transfer, or a cashier’s check;

(b) if permitted by the Committee, certificates for shares of Company stock that Participant owns, along with any forms needed to effect a transfer of those shares to the Company; the value of the shares, determined as of the effective date of the Option exercise, will be applied to the Exercise Price. Instead of surrendering shares of Company stock, Participant may attest to the ownership of those shares on a form provided by the Company and have the same number of shares subtracted from the Option shares issued to Participant. However, Participant may not surrender, or attest to the ownership of, shares of Company stock in payment of the Exercise Price of Participant’s Option if Participant’s action would cause the Company to recognize compensation expense (or additional compensation expense) with respect to this Option for financial reporting purposes;

(c) cashless exercise through irrevocable directions to a securities broker approved by the Company to sell all or part of the Shares covered by this Option and to deliver to the Company from the sale proceeds an amount sufficient to pay the Exercise Price and any applicable Tax-Related Items (as defined below) withholding. The balance of the sale proceeds, if any, will be delivered to Participant unless otherwise provided in this Option Agreement. The directions must be given by signing a special notice of exercise form provided by the Company; or

(d) other method authorized by the Company;

provided, however, that the Company may restrict the available methods of payment due to facilitate compliance with applicable law or administration of the Plan. In particular, if Participant is located outside the United States, Participant should review the applicable provisions of the Appendix for any such restrictions that may currently apply.

6. Non-Transferability of Option. This Option may not be sold, assigned, transferred, pledged, hypothecated, or otherwise disposed of other than by will or by the laws of descent or distribution or court order and may be exercised during the lifetime of Participant only by Participant or unless otherwise permitted by the Committee on a case-by-case basis. The terms of the Plan and this Option Agreement will be binding upon the executors, administrators, heirs, successors and assigns of Participant.

7. Term of Option. This Option will in any event expire on the expiration date set forth in the Notice, which date is 10 years after the Date of Grant (five years after the Date of Grant if this option is designated as an ISO in the Notice of Stock Option Grant and Section 5.3 of the Plan applies).

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8. Taxes.

(a) Responsibility for Taxes. Participant acknowledges that, regardless of any action taken by the Company or a Parent, Subsidiary or Affiliate employing or retaining Participant (the “Employer”), the ultimate liability for all income tax, social insurance, payroll tax, fringe benefits tax, payment on account or other tax related items related to Participant’s participation in the Plan and legally applicable to Participant (“Tax-Related Items”) is and remains Participant’s responsibility and may exceed the amount actually withheld by the Company or the Employer, if any. Participant further acknowledges that the Company and/or the Employer (i) make no representations or undertakings regarding the treatment of any Tax-Related Items in connection with any aspect of this Option, including, but not limited to, the grant, vesting or exercise of this Option, the subsequent sale of Shares acquired pursuant to such exercise and the receipt of any dividends; and (ii) do not commit to and are under no obligation to structure the terms of the grant or any aspect of this Option to reduce or eliminate Participant’s liability for Tax-Related Items or achieve any particular tax result. Further, if Participant is subject to Tax-Related Items in more than one jurisdiction, Participant acknowledges that the Company and/or the Employer (or former employer, as applicable) may be required to withhold or account for Tax-Related Items in more than one jurisdiction. PARTICIPANT SHOULD CONSULT A TAX ADVISER APPROPRIATELY QUALIFIED IN EACH OF THE JURISDICTIONS, INCLUDING COUNTRY OR COUNTRIES IN WHICH PARTICIPANT RESIDES OR IS SUBJECT TO TAXATION BEFORE EXERCISING THE OPTION OR DISPOSING OF THE SHARES.

(b) Withholding. Prior to any relevant taxable or tax withholding event, as applicable, Participant agrees to make arrangements satisfactory to the Company and/or the Employer to fulfill all Tax-Related Items. In this regard, Participant authorizes the Company and/or the Employer, or their respective agents, at their discretion, to satisfy any withholding obligations for Tax-Related Items by one or a combination of the following:

| (i) | withholding from Participant’s wages or other cash compensation paid to Participant by the Company and/or the Employer or any Parent, Subsidiary or Affiliate; or

| (ii) | withholding from proceeds of the sale of Shares acquired at exercise of this Option either through a voluntary sale or through a mandatory sale arranged by the Company (on Participant’s behalf pursuant to this authorization and without further consent); or

| (iii) | withholding Shares to be issued upon exercise of the Option, provided the Company only withholds the number of Shares necessary to satisfy no more than the maximum statutory withholding amounts;

| (iv) | Participant’s payment of a cash amount (including by check representing readily available funds or a wire transfer); or

| (v) | any other arrangement approved by the Committee and permitted under applicable law;

all under such rules as may be established by the Committee and in compliance with the Company’s Insider Trading Policy and 10b5-1 Trading Plan Policy, if applicable; provided however, that if Participant is a Section 16 officer of the Company under the Exchange Act, then the Committee (as constituted in accordance with Rule 16b-3 under the Exchange Act) shall establish the method of withholding from alternatives (i)-(v) above, and the Committee shall establish the method prior to the Tax-Related Items withholding event.

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Depending on the withholding method, the Company may withhold or account for Tax-Related Items by considering applicable statutory withholding rates or other applicable withholding rates, including up to the maximum permissible statutory rate for Participant’s tax jurisdiction(s) in which case Participant will have no entitlement to the equivalent amount in Shares and may receive a refund of any over-withheld amount in cash in accordance with applicable law. If the obligation for Tax-Related Items is satisfied by withholding in Shares, for tax purposes, Participant is deemed to have been issued the full number of Exercised Shares; notwithstanding that a number of the Shares are held back solely for the purpose of satisfying the withholding obligation for Tax-Related Items.

Finally, Participant agrees to pay to the Company or the Employer any amount of Tax-Related Items that the Company or the Employer may be required to withhold or account for as a result of Participant’s participation in the Plan that cannot be satisfied by the means previously described. The Company may refuse to issue or deliver the Shares or the proceeds of the sale of Shares, if Participant fails to comply with Participant’s obligations in connection with the Tax-Related Items.

(c) Notice of Disqualifying Disposition of ISO Shares. If Participant is subject to Tax-Related Items in the United States and sells or otherwise disposes of any of the Shares acquired pursuant to an ISO on or before the later of (i) two years after the grant date, or (ii) one year after the exercise date, Participant will immediately notify the Company in writing of such disposition. Participant agrees that he or she may be subject to income tax withholding by the Company on the compensation income recognized from such early disposition of ISO Shares by payment in cash or out any wages or other cash compensation paid to Participant by the Company and/or the Employer or any Parent, Subsidiary or Affiliate.

9. Nature of Grant. By accepting the Option, Participant acknowledges, understands and agrees that:

(a) the Plan is established voluntarily by the Company, it is discretionary in nature and it may be modified, amended, suspended or terminated by the Company at any time, to the extent permitted by the Plan;

(b) the grant of the Option is exceptional, voluntary and occasional and does not create any contractual or other right to receive future grants of options, or benefits in lieu of options, even if options have been granted in the past;

(c) all decisions with respect to future options or other grants, if any, will be at the sole discretion of the Company;

(d) Participant is voluntarily participating in the Plan;

(e) the Option and Participant’s participation in the Plan will not create a right to employment or be interpreted as forming or amending an employment or service contract with the Company, the Employer or any Parent, Subsidiary or Affiliate, and shall not interfere with the ability of the Company, the Employer or any Parent, Subsidiary or Affiliate, as applicable, to terminate Participant’s employment or service relationship (if any);

(f) the Option and the Shares subject to the Option, and the income from and value of same, are not intended to replace any pension rights or compensation;

(g) the Option and the Shares subject to the Option, and the income from and value of same, are not part of normal or expected compensation for any purpose, including, but not limited to, calculating any severance, resignation, termination, redundancy, dismissal, end-of-service payments, bonuses, long-service awards, pension or retirement or welfare benefits or similar payments;

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(h) unless otherwise agreed with the Company, the Option and the Shares subject to the Option, and the income from and value of same, are not granted as consideration for, or in connection with, the service Participant may provide as a director of a Parent, Subsidiary or Affiliate;

(i) the future value of the Shares underlying the Option is unknown, indeterminable and cannot be predicted with certainty; if the underlying Shares do not increase in value, the Option will have no value; if Participant exercises the Option and acquires Shares, the value of such Shares may increase or decrease, even below the Exercise Price;

(j) no claim or entitlement to compensation or damages will arise from forfeiture of the Option resulting from Participant’s termination of Service (regardless of the reason for such termination and whether or not later found to be invalid or in breach of employment laws in the jurisdiction where Participant is employed or the terms of Participant’s employment agreement, if any); and

(k) neither the Company, the Employer nor any Parent, Subsidiary or Affiliate will be liable for any foreign exchange rate fluctuation between Participant’s local currency and the United States Dollar that may affect the value of the Option or of any amounts due to Participant pursuant to the exercise of the Option or the subsequent sale of any Shares acquired upon exercise.

10. No Advice Regarding Grant. The Company is not providing any tax, legal or financial advice, nor is the Company making any recommendations regarding Participant’s participation in the Plan, or Participant’s acquisition or sale of the underlying Shares. Participant acknowledges, understands and agrees that he or she should consult with his or her own personal tax, legal and financial advisors regarding his or her participation in the Plan before taking any action related to the Plan.

11. Data Privacy. Participant hereby explicitly and unambiguously consents to the collection, use and transfer, in electronic or other form, of Participant’s personal data as described in this Option Agreement and any other Option grant materials by and among, as applicable, the Employer, the Company and any Parent, Subsidiary or Affiliate for the exclusive purpose of implementing, administering and managing Participant’s participation in the Plan.

Participant understands that the Company and the Employer may hold certain personal information about Participant, including, but not limited to, Participant’s name, home address, email address and telephone number, date of birth, social insurance number, passport number or other identification number (e.g., resident registration number), salary, nationality, job title, any shares of stock or directorships held in the Company, details of all Options or any other entitlement to shares of stock awarded, canceled, exercised, vested, unvested or outstanding in Participant’s favor (“Data”), for the exclusive purpose of implementing, administering and managing the Plan.

Participant understands that Data will be transferred to E*TRADE Financial Services, Solium-Shareworks, or other third party (“Online Administrator”) and its affiliated companies or such other stock plan service provider as may be designated by the Company from time to time, which is assisting the Company with the implementation, administration and management of the Plan. Participant understands that the recipients of Data may be located in the United States or elsewhere, and that the recipients’ country may have different data privacy laws and protections than Participant’s country. Participant understands that if he or she resides outside the United States, he or she may request a list with the names and addresses of any potential recipients of Data by contacting his or her local human resources representative. Participant authorizes the Company, [Online Administrator], or such other stock plan service provider as may be designated by the Company from time to time, and any other possible recipients which may assist the Company (presently or in the future) with implementing, administering and managing the Plan to receive, possess, use, retain and transfer Data, in electronic or other form, for the sole purpose of implementing, administering and managing his or her participation in the Plan. Participant understands that Data will be held only as

29

long as is necessary to implement, administer and manage Participant’s participation in the Plan. Participant understands if he or she resides outside the United States, he or she may, at any time, view Data, request information about the storage and processing of Data, require any necessary amendments to Data or refuse or withdraw the consents herein, in any case without cost, by contacting his or her local human resources representative. Further, Participant understands that he or she is providing the consents herein on a purely voluntary basis. If Participant does not consent, or if Participant later seeks to revoke his or her consent, his or her employment status or service with the Employer will not be affected; the only consequence of refusing or withdrawing Participant’s consent is that the Company would not be able to grant Options or other equity awards to Participant or administer or maintain such awards. Therefore, Participant understands that refusing or withdrawing his or her consent may affect Participant’s ability to participate in the Plan. For more information on the consequences of Participant’s refusal to consent or withdrawal of consent, Participant understands that he or she may contact his or her local human resources representative.

Finally, upon request of the Company or the Employer, Participant agrees to provide an executed data privacy consent form (or any other agreements or consents) that the Company or the Employer may deem necessary to obtain from Participant for the purpose of administering Participant’s participation in the Plan in compliance with the data privacy laws in Participant’s country, either now or in the future. Participant understands and agrees that Participant will not be able to participate in the Plan if Participant fails to provide any such consent or agreement requested by the Company and/or the Employer.

12. Language. Participant acknowledges that he or she is sufficiently proficient in English to understand the terms and conditions of this Option Agreement. Furthermore, if Participant has received this Option Agreement, or any other document related to the Option and/or the Plan translated into a language other than English and if the meaning of the translated version is different than the English version, the English version will control.

13. Appendix. Notwithstanding any provisions in this Option Agreement, the Option will be subject to any special terms and conditions set forth in any appendix to this Option Agreement for Participant’s country. Moreover, if Participant relocates to one of the countries included in the Appendix, the special terms and conditions for such country will apply to Participant, to the extent the Company determines that the application of such terms and conditions is necessary or advisable for legal or administrative reasons. The Appendix constitutes part of this Option Agreement.

14. Imposition of Other Requirements. The Company reserves the right to impose other requirements on Participant’s participation in the Plan, on the Option and on any Shares purchased upon exercise of the Option, to the extent the Company determines it is necessary or advisable for legal or administrative reasons, and to require Participant to sign any additional agreements or undertakings that may be necessary to accomplish the foregoing.

15. Acknowledgement. The Company and Participant agree that the Option is granted under and governed by the Notice, this Option Agreement and the provisions of the Plan (incorporated herein by reference). Participant: (a) acknowledges receipt of a copy of the Plan and the Plan prospectus, (b) represents that Participant has carefully read and is familiar with their provisions, and (c) hereby accepts the Option subject to all of the terms and conditions set forth herein and those set forth in the Plan and the Notice.

16. Entire Agreement; Enforcement of Rights. This Option Agreement, the Plan and the Notice constitute the entire agreement and understanding of the parties relating to the subject matter herein and supersede all prior discussions between them. Any prior agreements, commitments or negotiations concerning the purchase of the Shares hereunder are superseded. No adverse modification of, or adverse amendment to, this Option Agreement, nor any waiver of any rights under this Option Agreement, will be effective unless in writing and signed by the parties to this Option Agreement (which

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writing and signing may be electronic). The failure by either party to enforce any rights under this Option Agreement will not be construed as a waiver of any rights of such party.

17. Compliance with Laws and Regulations. The issuance of Shares will be subject to and conditioned upon compliance by the Company and Participant with all applicable state, federal and foreign laws and regulations and with all applicable requirements of any stock exchange or automated quotation system on which the Company’s Shares may be listed or quoted at the time of such issuance or transfer. Participant understands that the Company is under no obligation to register or qualify the Shares with any state, federal or foreign securities commission or to seek approval or clearance from any governmental authority for the issuance or sale of the Shares. Further, Participant agrees that the Company shall have unilateral authority to amend the Plan and this Option Agreement without Participant’s consent to the extent necessary to comply with securities or other laws applicable to issuance of Shares. Finally, the Shares issued pursuant to this Option Agreement shall be endorsed with appropriate legends, if any, determined by the Company.

18. Severability. If one or more provisions of this Option Agreement are held to be unenforceable under applicable law, then such provision will be enforced to the maximum extent possible given the intent of the parties hereto. If such clause or provision cannot be so enforced, then (a) such provision will be excluded from this Option Agreement, (b) the balance of this Option Agreement will be interpreted as if such provision were so excluded and (c) the balance of this Option Agreement will be enforceable in accordance with its terms.

19. Governing Law and Venue. This Option Agreement and all acts and transactions pursuant hereto and the rights and obligations of the parties hereto will be governed, construed and interpreted in accordance with the laws of the State of Delaware, without giving effect to such state’s conflict of laws rules.

Any and all disputes relating to, concerning or arising from this Option Agreement, or relating to, concerning or arising from the relationship between the parties evidenced by the Plan or this Option Agreement, will be brought and heard exclusively in the United States District Court for the District of Northern California or the Superior Court of California, County of San Mateo. Each of the parties hereby represents and agrees that such party is subject to the personal jurisdiction of said courts; hereby irrevocably consents to the jurisdiction of such courts in any legal or equitable proceedings related to, concerning or arising from such dispute, and waives, to the fullest extent permitted by law, any objection which such party may now or hereafter have that the laying of the venue of any legal or equitable proceedings related to, concerning or arising from such dispute which is brought in such courts is improper or that such proceedings have been brought in an inconvenient forum.

20. No Rights as Employee, Director or Consultant. Nothing in this Option Agreement will affect in any manner whatsoever any right or power of the Company, or a Parent, Subsidiary or Affiliate, to terminate Participant’s Service, for any reason, with or without Cause.

21. Consent to Electronic Delivery of All Plan Documents and Disclosures. By Participant’s acceptance of the Notice (whether in writing or electronically), Participant and the Company agree that this Option is granted under and governed by the terms and conditions of the Plan, the Notice and this Option Agreement. Participant has reviewed the Plan, the Notice and this Option Agreement in their entirety, has had an opportunity to obtain the advice of counsel prior to executing the Notice and Agreement, and fully understands all provisions of the Plan, the Notice and this Option Agreement. Participant hereby agrees to accept as binding, conclusive and final all decisions or interpretations of the Committee upon any questions relating to the Plan, the Notice and this Option Agreement. Participant further agrees to notify the Company upon any change in the residence address. By acceptance of this Option, Participant agrees to participate in the Plan through an on-line or electronic system established and maintained by the Company or a third party designated by the Company and consents to the electronic delivery of the Notice, this Option Agreement, the Plan, account statements, Plan prospectuses

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required by the SEC, U.S. financial reports of the Company, and all other documents that the Company is required to deliver to its security holders (including, without limitation, annual reports and proxy statements) or other communications or information related to the Option and current or future participation in the Plan. Electronic delivery may include the delivery of a link to the Company intranet or the internet site of a third party involved in administering the Plan, the delivery of the document via e-mail or such other delivery determined at the Company’s discretion. Participant acknowledges that Participant may receive from the Company a paper copy of any documents delivered electronically at no cost if Participant contacts the Company by telephone, through a postal service or electronic mail to Stock Administration. Participant further acknowledges that Participant will be provided with a paper copy of any documents delivered electronically if electronic delivery fails; similarly, Participant understands that Participant must provide on request to the Company or any designated third party a paper copy of any documents delivered electronically if electronic delivery fails. Also, Participant understands that Participant’s consent may be revoked or changed, including any change in the electronic mail address to which documents are delivered (if Participant has provided an electronic mail address), at any time by notifying the Company of such revised or revoked consent by telephone, postal service or electronic mail to Stock Administration.

22. Insider Trading Restrictions/Market Abuse Laws. Participant acknowledges that, depending on Participant’s country of residence, the broker’s country, or the country in which the Shares are listed, Participant may be subject to insider trading restrictions and/or market abuse laws in applicable jurisdictions, which may affect Participant’s ability to directly or indirectly, accept, acquire, sell or attempt to sell or otherwise dispose of Shares, or rights to Shares (e.g., Options), or rights linked to the value of Shares, during such times as Participant is considered to have “inside information” regarding the Company (as defined by the laws or regulations in the applicable jurisdiction). Local insider trading laws and regulations may prohibit the cancellation or amendment of orders Participant placed before possessing the inside information. Furthermore, Participant may be prohibited from (i) disclosing the inside information to any third party, including fellow employees (other than on a “need to know” basis) and (ii) “tipping” third parties or causing them to otherwise buy or sell securities. Any restrictions under these laws or regulations are separate from and in addition to any restrictions that may be imposed under any applicable Company insider trading policy. Participant acknowledges that it is Participant’s responsibility to comply with any applicable restrictions and understands that Participant should consult his or her personal legal advisor on such matters. In addition, Participant acknowledges that he or she read the Company’s Insider Trading Policy, and agrees to comply with such policy, as it may be amended from time to time, whenever Participant acquires or disposes of the Company’s securities.

23. Foreign Asset/Account, Exchange Control and Tax Reporting. Participant may be subject to foreign asset/account, exchange control and/or tax reporting requirements as a result of the acquisition, holding and/or transfer of Shares or cash resulting from his or her participation in the Plan. Participant may be required to report such accounts, assets, the balances therein, the value thereof and/or the transactions related thereto to the applicable authorities in Participant’s country and/or repatriate funds received in connection with the Plan within certain time limits or according to specified procedures. Participant acknowledges that he or she is responsible for ensuring compliance with any applicable foreign asset/account, exchange control and tax reporting requirements and should consult his or her personal legal and tax advisors on such matters.

24. Award Subject to Company Clawback or Recoupment. The Option shall be subject to clawback or recoupment pursuant to any compensation clawback or recoupment policy adopted by the Board or required by law during the term of Participant’s employment or other Service that is applicable to Participant. In addition to any other remedies available under such policy, applicable law may require the cancellation of Participant’s Option (whether vested or unvested) and the recoupment of any gains realized with respect to Participant’s Option.

BY ACCEPTING THIS OPTION, PARTICIPANT AGREES TO ALL OF THE TERMS AND CONDITIONS DESCRIBED ABOVE AND IN THE PLAN.

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APPENDIX

SUTRO BIOPHARMA, INC.

2018 EQUITY INCENTIVE PLAN

GLOBAL STOCK OPTION AWARD AGREEMENT

COUNTRY SPECIFIC PROVISIONS FOR EMPLOYEES OUTSIDE THE U.S.

Terms and Conditions

This Appendix includes additional terms and conditions that govern the Option granted to Participant under the Plan if Participant resides and/or works in one of the countries below. This Appendix forms part of the Option Agreement. Any capitalized term used in this Appendix without definition will have the meaning ascribed to it in the Notice, the Option Agreement or the Plan, as applicable.

If Participant is a citizen or resident of a country, or is considered resident of a country, other than the one in which Participant is currently working, or Participant transfers employment and/or residency between countries after the Date of Grant, the Company will, in its sole discretion, determine to what extent the additional terms and conditions included herein will apply to Participant under these circumstances.

Notifications

This Appendix also includes information relating to exchange control, securities laws, foreign asset/account reporting and other issues of which Participant should be aware with respect to Participant’s participation in the Plan. The information is based on the securities, exchange control, foreign asset/account reporting and other laws in effect in the respective countries as of September, 2018. Such laws are complex and change frequently. As a result, Participant should not rely on the information herein as the only source of information relating to the consequences of Participant’s participation in the Plan because the information may be out of date at the time that Participant exercises the Option, sells Shares acquired under the Plan or takes any other action in connection with the Plan.

In addition, the information is general in nature and may not apply to Participant’s particular situation, and the Company is not in a position to assure Participant of any particular result. Accordingly, Participant should seek appropriate professional advice as to how the relevant laws in Participant’s country may apply to Participant’s situation.

Finally, if Participant is a citizen or resident of a country, or is considered resident of a country, other than the one in which Participant is currently working and/or residing, or Participant transfers employment and/or residency after the Date of Grant, the information contained herein may not apply to Participant in the same manner.

None

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SUTRO BIOPHARMA, INC.

2018 EQUITY INCENTIVE PLAN

GLOBAL NOTICE OF RESTRICTED STOCK UNIT AWARD

Unless otherwise defined herein, the terms defined in the Sutro Biopharma, Inc. (the “Company”) 2018 Equity Incentive Plan (the “Plan”) will have the same meanings in this Global Notice of Restricted Stock Unit Award and the electronic representation of this Global Notice of Restricted Stock Unit Award established and maintained by the Company or a third party designated by the Company (this “Notice”).

Name:

Address:

You (“Participant”) have been granted an award of Restricted Stock Units (“RSUs”) under the Plan subject to the terms and conditions of the Plan, this Notice and the attached Global Restricted Stock Unit Award Agreement (the “Agreement”), including any applicable country-specific provisions in the appendix attached hereto (the “Appendix”), which constitutes part of the Agreement.

Grant Number:

Number of RSUs:

Date of Grant:

Vesting Commencement Date:

Expiration Date: | The earlier to occur of: (a) the date on which settlement of all RSUs granted hereunder occurs and (b) the tenth anniversary of the Date of Grant. This RSU expires earlier if Participant’s Service terminates earlier, as described in the Agreement.

Vesting Schedule: | Subject to the limitations set forth in this Notice, the Plan and the Agreement, the RSUs will vest in accordance with the following schedule: [insert applicable vesting schedule]

By accepting (whether in writing, electronically or otherwise) the RSUs, Participant acknowledges and agrees to the following:

| 1) | Participant understands that Participant’s employment or consulting relationship or Service with the Company or a Parent or Subsidiary or Affiliate is for an unspecified duration, can be terminated at any time (i.e., is “at-will”), except where otherwise prohibited by applicable law, and that nothing in this Notice, the Agreement or the Plan changes the nature of that relationship. Participant acknowledges that the vesting of the RSUs pursuant to this Notice is subject to Participant’s continuing Service as an Employee, Director or Consultant. Participant agrees and acknowledges that the Vesting Schedule may change prospectively in the event that Participant’s service status changes between full- and part-time and/or in the event Participant is on a leave of absence, in accordance with Company policies relating to work schedules and vesting of Awards or as determined by the Committee.

| 2) | This grant is made under and governed by the Plan, the Agreement and this Notice, and this Notice is subject to the terms and conditions of the Agreement and the Plan, both of which are incorporated herein by reference. Participant has read the Notice, the Agreement and the Plan.

| 3) | Participant has read the Company’s Insider Trading Policy, and agrees to comply with such policy, as it may be amended from time to time, whenever Participant acquires or disposes of the Company’s securities.

| 4) | By accepting the RSUs, Participant consents to electronic delivery and participation as set forth in the Agreement.

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SUTRO BIOPHARMA, INC.

2018 EQUITY INCENTIVE PLAN

GLOBAL RESTRICTED STOCK UNIT AWARD AGREEMENT

Unless otherwise defined in this Global Restricted Stock Unit Award Agreement (this “Agreement”), any capitalized terms used herein will have the same meaning ascribed to them in the Sutro Biopharma, Inc. 2018 Equity Incentive Plan (the “Plan”).

Participant has been granted Restricted Stock Units (“RSUs”) subject to the terms, restrictions and conditions of the Plan, the Global Notice of Restricted Stock Unit Award (the “Notice”) and this Agreement, including any applicable country-specific provisions in the appendix attached hereto (the “Appendix”), which constitutes part of this Agreement. In the event of a conflict between the terms and conditions of the Plan and the terms and conditions of the Notice or this Agreement, the terms and conditions of the Plan shall prevail.

1. Settlement. Settlement of RSUs will be made within 30 days following the applicable date of vesting under the Vesting Schedule set forth in the Notice. Settlement of RSUs will be in Shares. No fractional RSUs or rights for fractional Shares shall be created pursuant to this Agreement.

2. No Stockholder Rights. Unless and until such time as Shares are issued in settlement of vested RSUs, Participant will have no ownership of the Shares allocated to the RSUs and will have no rights to dividends or to vote such Shares.

3. Dividend Equivalents. Dividends, if any (whether in cash or Shares), will not be credited to Participant.

4. Non-Transferability of RSUs. The RSUs and any interest therein will not be sold, assigned, transferred, pledged, hypothecated, or otherwise disposed of in any manner other than by will or by the laws of descent or distribution or court order or unless otherwise permitted by the Committee on a case-by-case basis.

5. Termination. If Participant’s Service terminates for any reason, all unvested RSUs will be forfeited to the Company forthwith, and all rights of Participant to such RSUs will immediately terminate without payment of any consideration to Participant. Participant’s Service will be considered terminated (regardless of the reason for such termination and whether or not later found to be invalid or in breach of employment laws in the jurisdiction where Participant is employed or the terms of Participant’s employment agreement, if any) as of the date Participant is no longer actively providing services and Participant’s Service will not be extended by any notice period (e.g., Participant’s Service would not include a period of “garden leave” or similar period mandated under employment laws in the jurisdiction where Participant is employed or the terms of Participant’s employment agreement, if any). Participant acknowledges and agrees that the Vesting Schedule may change prospectively in the event Participant’s service status changes between full- and part-time and/or in the event Participant is on a leave of absence, in accordance with Company policies relating to work schedules and vesting of awards or as determined by the Committee. In case of any dispute as to whether and when a termination of Service has occurred, the Committee will have sole discretion to determine whether such termination of Service has occurred and the effective date of such termination (including whether Participant may still be considered to be actively providing Services while on a leave of absence).

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6. Taxes.

(a) Responsibility for Taxes. Participant acknowledges that, regardless of any action taken by the Company or a Parent, Subsidiary or Affiliate employing or retaining Participant (the “Employer”), the ultimate liability for all income tax, social insurance, payroll tax, fringe benefits tax, payment on account or other tax-related items related to Participant’s participation in the Plan and legally applicable to Participant (“Tax-Related Items”) is and remains Participant’s responsibility and may exceed the amount actually withheld by the Company or the Employer, if any. Participant further acknowledges that the Company and/or the Employer (i) make no representations or undertakings regarding the treatment of any Tax-Related Items in connection with any aspect of the RSUs, including, but not limited to, the grant, vesting or settlement of the RSUs and the subsequent sale of Shares acquired pursuant to such settlement and the receipt of any dividends, and (ii) do not commit to and are under no obligation to structure the terms of the grant or any aspect of the RSUs to reduce or eliminate Participant’s liability for Tax-Related Items or achieve any particular tax result. Further, if Participant is subject to Tax-Related Items in more than one jurisdiction, Participant acknowledges that the Company and/or the Employer (or former employer, as applicable) may be required to withhold or account for Tax-Related Items in more than one jurisdiction. PARTICIPANT SHOULD CONSULT A TAX ADVISER APPROPRIATELY QUALIFIED IN EACH OF THE JURISDICTIONS, INCLUDING COUNTRY OR COUNTRIES IN WHICH PARTICIPANT RESIDES OR IS SUBJECT TO TAXATION.

(b) Withholding. Prior to any relevant taxable or tax withholding event, as applicable, Participant agrees to make arrangements satisfactory to the Company and/or the Employer to fulfill all Tax-Related Items. In this regard, Participant authorizes the Company and/or the Employer, or their respective agents, at their discretion, to satisfy any withholding obligations for Tax-Related Items by one or a combination of the following:

| (i) | withholding from Participant’s wages or other cash compensation paid to Participant by the Company and/or the Employer or any Parent, Subsidiary or Affiliate; or

| (ii) | withholding from proceeds of the sale of Shares acquired upon settlement of the RSUs either through a voluntary sale or through a mandatory sale arranged by the Company (on Participant’s behalf pursuant to this authorization and without further consent); or

| (iii) | withholding Shares to be issued upon settlement of the RSUs, provided the Company only withholds the number of Shares necessary to satisfy no more than the maximum statutory withholding amounts; or

| (iv) | Participant’s payment of a cash amount (including by check representing readily available funds or a wire transfer); or

| (v) | any other arrangement approved by the Committee and permitted under applicable law;

all under such rules as may be established by the Committee and in compliance with the Company’s Insider Trading Policy and 10b5-1 Trading Plan Policy, if applicable; provided however, that if Participant is a Section 16 officer of the Company under the Exchange Act, then unless determined otherwise by the Committee in advance of a Tax-Related Items withholding event, the method of withholding for this RSU will be (ii) above.

Depending on the withholding method, the Company may withhold or account for Tax-Related Items by considering applicable statutory withholding rates or other applicable withholding rates, including up to the maximum permissible statutory rate for Participant’s tax jurisdiction(s) in which case

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Participant will have no entitlement to the equivalent amount in Shares and may receive a refund of any over-withheld amount in cash in accordance with applicable law. If the obligation for Tax-Related Items is satisfied by withholding in Shares, for tax purposes, Participant is deemed to have been issued the full number of Shares subject to the vested RSUs, notwithstanding that a number of the Shares are held back solely for the purpose of satisfying the withholding obligation for Tax-Related Items.

Finally, Participant agrees to pay to the Company or the Employer any amount of Tax-Related Items that the Company or the Employer may be required to withhold or account for as a result of Participant’s participation in the Plan that cannot be satisfied by the means previously described. The Company may refuse to issue or deliver the Shares or the proceeds of the sale of Shares, if Participant fails to comply with Participant’s obligations in connection with the Tax-Related Items.

7. Nature of Grant. By accepting the RSUs, Participant acknowledges, understands and agrees that:

(a) the Plan is established voluntarily by the Company, it is discretionary in nature and it may be modified, amended, suspended or terminated by the Company at any time, to the extent permitted by the Plan;

(b) the grant of the RSUs is exceptional, voluntary and occasional and does not create any contractual or other right to receive future grants of RSUs, or benefits in lieu of RSUs, even if RSUs have been granted in the past;

(c) all decisions with respect to future RSUs or other grants, if any, will be at the sole discretion of the Company;

(d) Participant is voluntarily participating in the Plan;

(e) the RSUs and Participant’s participation in the Plan will not create a right to employment or be interpreted as forming or amending an employment or service contract with the Company, the Employer or any Parent, Subsidiary or Affiliate and shall not interfere with the ability of the Company, the Employer or any Parent, Subsidiary or Affiliate, as applicable, to terminate Participant’s employment or service relationship (if any);

(f) the RSUs and the Shares subject to the RSUs, and the income from and value of same, are not intended to replace any pension rights or compensation;

(g) the RSUs and the Shares subject to the RSUs, and the income from and value of same, are not part of normal or expected compensation for any purpose, including, but not limited to, calculating any severance, resignation, termination, redundancy, dismissal, end-of-service payments, bonuses, long-service awards, pension or retirement or welfare benefits or similar payments;

(h) unless otherwise agreed with the Company, the RSUs and the Shares subject to the RSUs, and the income from and value of same, are not granted as consideration for, or in connection with, the service Participant may provide as a director of a Parent, Subsidiary or Affiliate;

(i) the future value of the underlying Shares is unknown, indeterminable and cannot be predicted with certainty;

(j) no claim or entitlement to compensation or damages will arise from forfeiture of the RSUs resulting from Participant’s termination of Service (regardless of the reason for such termination

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and whether or not later found to be invalid or in breach of employment laws in the jurisdiction where Participant is employed or the terms of Participant’s employment agreement, if any); and

(k) neither the Company, the Employer nor any Parent, Subsidiary or Affiliate will be liable for any foreign exchange rate fluctuation between Participant’s local currency and the United States Dollar that may affect the value of the RSUs or of any amounts due to Participant pursuant to the settlement of the RSUs or the subsequent sale of any Shares acquired upon settlement.

8. No Advice Regarding Grant. The Company is not providing any tax, legal or financial advice, nor is the Company making any recommendations regarding Participant’s participation in the Plan, or Participant’s acquisition or sale of the underlying Shares. Participant acknowledges, understands and agrees he or she should consult with his or her own personal tax, legal and financial advisors regarding his or her participation in the Plan before taking any action related to the Plan.

9. Data Privacy. Participant hereby explicitly and unambiguously consents to the collection, use and transfer, in electronic or other form, of Participant’s personal data as described in this Agreement and any other RSU grant materials by and among, as applicable, the Employer, the Company and any Parent, Subsidiary or Affiliate for the exclusive purpose of implementing, administering and managing Participant’s participation in the Plan.

Participant understands that the Company and the Employer may hold certain personal information about Participant, including, but not limited to, Participant’s name, home address, email address and telephone number, date of birth, social insurance number, passport number or other identification number (e.g., resident registration number), salary, nationality, job title, any shares of stock or directorships held in the Company, details of all RSUs or any other entitlement to shares of stock awarded, canceled, exercised, vested, unvested or outstanding in Participant’s favor (“Data”), for the exclusive purpose of implementing, administering and managing the Plan.

Participant understands that Data will be transferred to E*TRADE Financial Services, Solium-Shareworks, or other third party (“Online Administrator”) and its affiliated companies or such other stock plan service provider as may be designated by the Company from time to time, which is assisting the Company with the implementation, administration and management of the Plan. Participant understands that the recipients of Data may be located in the United States or elsewhere, and that the recipients’ country may have different data privacy laws and protections than Participant’s country. Participant understands that if he or she resides outside the United States, he or she may request a list with the names and addresses of any potential recipients of Data by contacting his or her local human resources representative. Participant authorizes the Company, [Online Administrator], or such other stock plan service provider as may be designated by the Company from time to time, and any other possible recipients which may assist the Company (presently or in the future) with implementing, administering and managing the Plan to receive, possess, use, retain and transfer Data, in electronic or other form, for the sole purpose of implementing, administering and managing his or her participation in the Plan. Participant understands that Data will be held only as long as is necessary to implement, administer and manage Participant’s participation in the Plan. Participant understands if he or she resides outside the United States, he or she may, at any time, view Data, request information about the storage and processing of Data, require any necessary amendments to Data or refuse or withdraw the consents herein, in any case without cost, by contacting his or her local human resources representative. Further, Participant understands that he or she is providing the consents herein on a purely voluntary basis. If Participant does not consent, or if Participant later seeks to revoke his or her consent, his or her employment status or service with the Employer will not be affected; the only consequence of refusing or withdrawing Participant’s consent is that the Company would not be able to grant RSUs or other equity awards to Participant or

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administer or maintain such awards. Therefore, Participant understands that refusing or withdrawing his or her consent may affect Participant’s ability to participate in the Plan. For more information on the consequences of Participant’s refusal to consent or withdrawal of consent, Participant understands that he or she may contact his or her local human resources representative.

Finally, upon request of the Company or the Employer, Participant agrees to provide an executed data privacy consent form (or any other agreements or consents) that the Company or the Employer may deem necessary to obtain from Participant for the purpose of administering Participant’s participation in the Plan in compliance with the data privacy laws in Participant’s country, either now or in the future. Participant understands and agrees that Participant will not be able to participate in the Plan if Participant fails to provide any such consent or agreement requested by the Company and/or the Employer.

10. Language. Participant acknowledges that he or she is sufficiently proficient in English to understand the terms and conditions of this Agreement. Furthermore, if Participant has received this Agreement or any other document related to the RSU and/or the Plan translated into a language other than English and if the meaning of the translated version is different than the English version, the English version will control.

11. Appendix. Notwithstanding any provisions in this Agreement, the RSUs will be subject to any special terms and conditions set forth in any appendix to this Agreement for Participant’s country. Moreover, if Participant relocates to one of the countries included in the Appendix, the special terms and conditions for such country will apply to Participant, to the extent the Company determines that the application of such terms and conditions is necessary or advisable for legal or administrative reasons. The Appendix constitutes part of this Agreement.

12. Imposition of Other Requirements. The Company reserves the right to impose other requirements on Participant’s participation in the Plan, on the RSUs and on any Shares acquired under the Plan, to the extent the Company determines it is necessary or advisable for legal or administrative reasons, and to require Participant to sign any additional agreements or undertakings that may be necessary to accomplish the foregoing.

13. Acknowledgement. The Company and Participant agree that the RSUs are granted under and governed by the Notice, this Agreement and the provisions of the Plan (incorporated herein by reference). Participant: (a) acknowledges receipt of a copy of the Plan and the Plan prospectus, (b) represents that Participant has carefully read and is familiar with their provisions, and (c) hereby accepts the RSUs subject to all of the terms and conditions set forth herein and those set forth in the Plan and the Notice.

14. Entire Agreement; Enforcement of Rights. This Agreement, the Plan and the Notice constitute the entire agreement and understanding of the parties relating to the subject matter herein and supersede all prior discussions between them. Any prior agreements, commitments or negotiations concerning the purchase of the Shares hereunder are superseded. No adverse modification of or adverse amendment to this Agreement, nor any waiver of any rights under this Agreement, will be effective unless in writing and signed by the parties to this Agreement (which writing and signing may be electronic). The failure by either party to enforce any rights under this Agreement will not be construed as a waiver of any rights of such party.

15. Compliance with Laws and Regulations. The issuance of Shares will be subject to and conditioned upon compliance by the Company and Participant with all applicable state, federal and foreign laws and regulations and with all applicable requirements of any stock exchange or automated quotation system on which the Company’s Shares may be listed or quoted at the time of such issuance or

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transfer. Participant understands that the Company is under no obligation to register or qualify the Shares with any state, federal or foreign securities commission or to seek approval or clearance from any governmental authority for the issuance or sale of the Shares. Further, Participant agrees that the Company shall have unilateral authority to amend the Plan and this RSU Agreement without Participant’s consent to the extent necessary to comply with securities or other laws applicable to issuance of Shares. Finally, the Shares issued pursuant to this RSU Agreement shall be endorsed with appropriate legends, if any, determined by the Company.

16. Severability. If one or more provisions of this Agreement are held to be unenforceable under applicable law, then such provision will be enforced to the maximum extent possible given the intent of the parties hereto. If such clause or provision cannot be so enforced, then (a) such provision will be excluded from this Agreement, (b) the balance of this Agreement will be interpreted as if such provision were so excluded and (c) the balance of this Agreement will be enforceable in accordance with its terms.

17. Governing Law and Venue. This Agreement and all acts and transactions pursuant hereto and the rights and obligations of the parties hereto will be governed, construed and interpreted in accordance with the laws of the State of Delaware, without giving effect to such state’s conflict of laws rules.

Any and all disputes relating to, concerning or arising from this Agreement, or relating to, concerning or arising from the relationship between the parties evidenced by the Plan or this Agreement, will be brought and heard exclusively in the United States District Court for the District of Northern California or the Superior Court of California, County of San Mateo. Each of the parties hereby represents and agrees that such party is subject to the personal jurisdiction of said courts; hereby irrevocably consents to the jurisdiction of such courts in any legal or equitable proceedings related to, concerning or arising from such dispute, and waives, to the fullest extent permitted by law, any objection which such party may now or hereafter have that the laying of the venue of any legal or equitable proceedings related to, concerning or arising from such dispute which is brought in such courts is improper or that such proceedings have been brought in an inconvenient forum.

18. No Rights as Employee, Director or Consultant. Nothing in this Agreement will affect in any manner whatsoever any right or power of the Company, or a Parent, Subsidiary or Affiliate, to terminate Participant’s Service, for any reason, with or without Cause.

19. Consent to Electronic Delivery of All Plan Documents and Disclosures. By Participant’s acceptance of the Notice (whether in writing or electronically), Participant and the Company agree that the RSUs are granted under and governed by the terms and conditions of the Plan, the Notice and this Agreement. Participant has reviewed the Plan, the Notice and this Agreement in their entirety, has had an opportunity to obtain the advice of counsel prior to executing this Notice and Agreement, and fully understands all provisions of the Plan, the Notice and this Agreement. Participant hereby agrees to accept as binding, conclusive and final all decisions or interpretations of the Committee upon any questions relating to the Plan, the Notice and this Agreement. Participant further agrees to notify the Company upon any change in Participant’s residence address. By acceptance of the RSUs, Participant agrees to participate in the Plan through an on-line or electronic system established and maintained by the Company or a third party designated by the Company and consents to the electronic delivery of the Notice, this Agreement, the Plan, account statements, Plan prospectuses required by the SEC, U.S. financial reports of the Company, and all other documents that the Company is required to deliver to its security holders (including, without limitation, annual reports and proxy statements) or other communications or information related to the RSUs and current or future participation in the Plan. Electronic delivery may include the delivery of a link to the Company intranet or the internet site of a third party involved in administering the Plan, the delivery of the document via e-mail or such other delivery determined at the Company’s discretion. Participant acknowledges that Participant may receive

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from the Company a paper copy of any documents delivered electronically at no cost if Participant contacts the Company by telephone, through a postal service or electronic mail to Stock Administration. Participant further acknowledges that Participant will be provided with a paper copy of any documents delivered electronically if electronic delivery fails; similarly, Participant understands that Participant must provide on request to the Company or any designated third party a paper copy of any documents delivered electronically if electronic delivery fails. Also, Participant understands that Participant’s consent may be revoked or changed, including any change in the electronic mail address to which documents are delivered (if Participant has provided an electronic mail address), at any time by notifying the Company of such revised or revoked consent by telephone, postal service or electronic mail to Stock Administration.

20. Insider Trading Restrictions/Market Abuse Laws. Participant acknowledges that, depending on Participant’s country of residence, the broker’s country, or the country in which the Shares are listed, Participant may be subject to insider trading restrictions and/or market abuse laws in applicable jurisdictions, which may affect Participant’s ability to directly or indirectly, accept, acquire, sell or attempt to sell or otherwise dispose of Shares, or rights to Shares (e.g., RSUs), or rights linked to the value of Shares, during such times as Participant is considered to have “inside information” regarding the Company (as defined by the laws or regulations in the applicable jurisdiction). Local insider trading laws and regulations may prohibit the cancellation or amendment of orders Participant placed before possessing the inside information. Furthermore, Participant may be prohibited from (i) disclosing the inside information to any third party, including fellow employees (other than on a “need to know” basis) and (ii) “tipping” third parties or causing them to otherwise buy or sell securities. Any restrictions under these laws or regulations are separate from and in addition to any restrictions that may be imposed under any applicable Company insider trading policy. Participant acknowledges that it is Participant’s responsibility to comply with any applicable restrictions and understands that Participant should consult his or her personal legal advisor on such matters. In addition, Participant acknowledges that he or she read the Company’s Insider Trading Policy, and agrees to comply with such policy, as it may be amended from time to time, whenever Participant acquires or disposes of the Company’s securities.

21. Foreign Asset/Account, Exchange Control and Tax Reporting. Participant may be subject to foreign asset/account, exchange control and/or tax reporting requirements as a result of the acquisition, holding and/or transfer of Shares or cash resulting from his or her participation in the Plan. Participant may be required to report such accounts, assets, the balances therein, the value thereof and/or the transactions related thereto to the applicable authorities in Participant’s country and/or repatriate funds received in connection with the Plan within certain time limits or according to specified procedures. Participant acknowledges that he or she is responsible for ensuring compliance with any applicable foreign asset/account, exchange control and tax reporting requirements and should consult his or her personal legal and tax advisors on such matters.

22. Code Section 409A. For purposes of this Agreement, a termination of employment will be determined consistent with the rules relating to a “separation from service” as defined in Section 409A of the Internal Revenue Code and the regulations thereunder (“Section 409A”). Notwithstanding anything else provided herein, to the extent any payments provided under this RSU Agreement in connection with Participant’s termination of employment constitute deferred compensation subject to Section 409A, and Participant is deemed at the time of such termination of employment to be a “specified employee” under Section 409A, then such payment shall not be made or commence until the earlier of (i) the expiration of the six-month period measured from Participant’s separation from service from the Company or (ii) the date of Participant’s death following such a separation from service; provided, however, that such deferral shall only be effected to the extent required to avoid adverse tax treatment to Participant including, without limitation, the additional tax for which Participant would otherwise be liable under Section 409A(a)(1)(B) in the absence of such a deferral. To the extent any payment under this RSU Agreement

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may be classified as a “short-term deferral” within the meaning of Section 409A, such payment shall be deemed a short-term deferral, even if it may also qualify for an exemption from Section 409A under another provision of Section 409A. Payments pursuant to this section are intended to constitute separate payments for purposes of Section 1.409A-2(b)(2) of the Treasury Regulations.

23. Award Subject to Company Clawback or Recoupment. The RSUs shall be subject to clawback or recoupment pursuant to any compensation clawback or recoupment policy adopted by the Board or required by law during the term of Participant’s employment or other Service that is applicable to Participant. In addition to any other remedies available under such policy, applicable law may require the cancellation of Participant’s RSUs (whether vested or unvested) and the recoupment of any gains realized with respect to Participant’s RSUs.

BY ACCEPTING THIS AWARD OF RSUS, PARTICIPANT AGREES TO ALL OF THE TERMS AND CONDITIONS DESCRIBED ABOVE AND IN THE PLAN.

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APPENDIX

SUTRO BIOPHARMA, INC.

2018 EQUITY INCENTIVE PLAN

GLOBAL RESTRICTED STOCK UNIT AWARD AGREEMENT

COUNTRY SPECIFIC PROVISIONS FOR EMPLOYEES OUTSIDE THE U.S.

Terms and Conditions

This Appendix includes additional terms and conditions that govern the RSUs granted to Participant under the Plan if Participant resides and/or works in one of the countries below. This Appendix forms part of the Agreement. Any capitalized term used in this Appendix without definition will have the meaning ascribed to it in the Notice, the Agreement or the Plan, as applicable.

If Participant is a citizen or resident of a country, or is considered resident of a country, other than the one in which Participant is currently working, or Participant transfers employment and/or residency between countries after the Date of Grant, the Company will, in its sole discretion, determine to what extent the additional terms and conditions included herein will apply to Participant under these circumstances.

Notifications

This Appendix also includes information relating to exchange control, securities laws, foreign asset/account reporting and other issues of which Participant should be aware with respect to Participant’s participation in the Plan. The information is based on the securities, exchange control, foreign asset/account reporting and other laws in effect in the respective countries as of September, 2018. Such laws are complex and change frequently. As a result, Participant should not rely on the information herein as the only source of information relating to the consequences of Participant’s participation in the Plan because the information may be out of date at the time that Participant vests in the RSUs, sells Shares acquired under the Plan or takes any other action in connection with the Plan.

In addition, the information is general in nature and may not apply to Participant’s particular situation, and the Company is not in a position to assure Participant of any particular result. Accordingly, Participant should seek appropriate professional advice as to how the relevant laws in Participant’s country may apply to Participant’s situation.

Finally, if Participant is a citizen or resident of a country, or is considered resident of a country, other than the one in which Participant is currently working and/or residing, or Participant transfers employment and/or residency after the Date of Grant, the information contained herein may not apply to Participant in the same manner.

None.

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SUTRO BIOPHARMA, INC.

2018 EQUITY INCENTIVE PLAN

GLOBAL NOTICE OF PERFORMANCE STOCK UNIT AWARD

Unless otherwise defined herein, the terms defined in the Sutro Biopharma, Inc. (the “Company”) 2018 Equity Incentive Plan (the “Plan”) will have the same meanings in this Global Notice of Performance Stock Unit Award and the electronic representation of this Global Notice of Performance Stock Unit Award established and maintained by the Company or a third party designated by the Company (this “Notice”).

Name:

Address:

You (“Participant”) have been granted an award of Performance Stock Units (“PSUs”) under the Plan subject to the terms and conditions of the Plan, this Notice and the attached Global Performance Stock Unit Award Agreement (the “Agreement”), including any applicable country-specific provisions in the appendix attached hereto (the “Appendix”), which constitutes part of the Agreement.

Grant Number:

Number of PSUs:

Date of Grant:

Vesting Commencement Date:

Expiration Date: | The earlier to occur of: (a) the date on which settlement of all PSUs granted hereunder occurs and (b) the tenth anniversary of the Date of Grant. This PSU expires earlier if Participant’s Service terminates earlier, as described in the Agreement.

Vesting Schedule: | Subject to the limitations set forth in this Notice, the Plan and the Agreement, the PSUs will vest in accordance with the following schedule: [insert applicable performance metrics and vesting schedule]

By accepting (whether in writing, electronically or otherwise) the PSUs, Participant acknowledges and agrees to the following:

| 1) | Participant understands that Participant’s employment or consulting relationship or Service with the Company or a Parent or Subsidiary or Affiliate is for an unspecified duration, can be terminated at any time (i.e., is “at-will”), except where otherwise prohibited by applicable law, and that nothing in this Notice, the Agreement or the Plan changes the nature of that relationship. Participant acknowledges that the vesting of the PSUs pursuant to this Notice is subject to Participant’s continuing Service as an Employee, Director or Consultant. Participant agrees and acknowledges that the Vesting Schedule may change prospectively in the event that Participant’s service status changes between full- and part-time and/or in the event Participant is on a leave of absence, in accordance with Company policies relating to work schedules and vesting of Awards or as determined by the Committee.

| 2) | This grant is made under and governed by the Plan, the Agreement and this Notice, and this Notice is subject to the terms and conditions of the Agreement and the Plan, both of which are incorporated herein by reference. Participant has read the Notice, the Agreement and the Plan.

| 3) | Participant has read the Company’s Insider Trading Policy, and agrees to comply with such policy, as it may be amended from time to time, whenever Participant acquires or disposes of the Company’s securities.

| 4) | By accepting the PSUs, Participant consents to electronic delivery and participation as set forth in the Agreement.

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SUTRO BIOPHARMA, INC.

2018 EQUITY INCENTIVE PLAN

GLOBAL PERFORMANCE STOCK UNIT AWARD AGREEMENT

Unless otherwise defined in this Global Performance Stock Unit Award Agreement (this “Agreement”), any capitalized terms used herein will have the same meaning ascribed to them in the Sutro Biopharma, Inc. 2018 Equity Incentive Plan (the “Plan”).

Participant has been granted Performance Stock Units (“PSUs”) subject to the terms, restrictions and conditions of the Plan, the Global Notice of Performance Stock Unit Award (the “Notice”) and this Agreement, including any applicable country-specific provisions in the appendix attached hereto (the “Appendix”), which constitutes part of this Agreement. In the event of a conflict between the terms and conditions of the Plan and the terms and conditions of the Notice or this Agreement, the terms and conditions of the Plan shall prevail.

1. Settlement. Settlement of PSUs will be made within 30 days following the applicable date of vesting under the Vesting Schedule set forth in the Notice. Settlement of PSUs will be in Shares. No fractional PSUs or rights for fractional Shares shall be created pursuant to this Agreement.

2. No Stockholder Rights. Unless and until such time as Shares are issued in settlement of vested PSUs, Participant will have no ownership of the Shares allocated to the PSUs and will have no rights to dividends or to vote such Shares.

3. Dividend Equivalents. Dividends, if any (whether in cash or Shares), will not be credited to Participant.

4. Non-Transferability of PSUs. The PSUs and any interest therein will not be sold, assigned, transferred, pledged, hypothecated, or otherwise disposed of in any manner other than by will or by the laws of descent or distribution or court order or unless otherwise permitted by the Committee on a case-by-case basis.

5. Termination. If Participant’s Service terminates for any reason, all unvested PSUs will be forfeited to the Company forthwith, and all rights of Participant to such PSUs will immediately terminate without payment of any consideration to Participant. Participant’s Service will be considered terminated (regardless of the reason for such termination and whether or not later found to be invalid or in breach of employment laws in the jurisdiction where Participant is employed or the terms of Participant’s employment agreement, if any) as of the date Participant is no longer actively providing services and Participant’s Service will not be extended by any notice period (e.g., Participant’s Service would not include a period of “garden leave” or similar period mandated under employment laws in the jurisdiction where Participant is employed or the terms of Participant’s employment agreement, if any). Participant acknowledges and agrees that the Vesting Schedule may change prospectively in the event Participant’s service status changes between full- and part-time and/or in the event Participant is on a leave of absence, in accordance with Company policies relating to work schedules and vesting of awards or as determined by the Committee. In case of any dispute as to whether and when a termination of Service has occurred, the Committee will have sole discretion to determine whether such termination of Service has occurred and the effective date of such termination (including whether Participant may still be considered to be actively providing Services while on a leave of absence).

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6. Taxes.

(a) Responsibility for Taxes. Participant acknowledges that, regardless of any action taken by the Company or a Parent, Subsidiary or Affiliate employing or retaining Participant (the “Employer”), the ultimate liability for all income tax, social insurance, payroll tax, fringe benefits tax, payment on account or other tax-related items related to Participant’s participation in the Plan and legally applicable to Participant (“Tax-Related Items”) is and remains Participant’s responsibility and may exceed the amount actually withheld by the Company or the Employer, if any. Participant further acknowledges that the Company and/or the Employer (i) make no representations or undertakings regarding the treatment of any Tax-Related Items in connection with any aspect of the PSUs, including, but not limited to, the grant, vesting or settlement of the PSUs and the subsequent sale of Shares acquired pursuant to such settlement and the receipt of any dividends, and (ii) do not commit to and are under no obligation to structure the terms of the grant or any aspect of the PSUs to reduce or eliminate Participant’s liability for Tax-Related Items or achieve any particular tax result. Further, if Participant is subject to Tax-Related Items in more than one jurisdiction, Participant acknowledges that the Company and/or the Employer (or former employer, as applicable) may be required to withhold or account for Tax-Related Items in more than one jurisdiction. PARTICIPANT SHOULD CONSULT A TAX ADVISER APPROPRIATELY QUALIFIED IN EACH OF THE JURISDICTIONS, INCLUDING COUNTRY OR COUNTRIES IN WHICH PARTICIPANT RESIDES OR IS SUBJECT TO TAXATION.

(b) Withholding. Prior to any relevant taxable or tax withholding event, as applicable, Participant agrees to make arrangements satisfactory to the Company and/or the Employer to fulfill all Tax-Related Items. In this regard, Participant authorizes the Company and/or the Employer, or their respective agents, at their discretion, to satisfy any withholding obligations for Tax-Related Items by one or a combination of the following:

| (i) | withholding from Participant’s wages or other cash compensation paid to Participant by the Company and/or the Employer or any Parent, Subsidiary or Affiliate; or

| (ii) | withholding from proceeds of the sale of Shares acquired upon settlement of the PSUs either through a voluntary sale or through a mandatory sale arranged by the Company (on Participant’s behalf pursuant to this authorization and without further consent); or

| (iii) | withholding Shares to be issued upon settlement of the PSUs, provided the Company only withholds the number of Shares necessary to satisfy no more than the maximum statutory withholding amounts; or

| (iv) | Participant’s payment of a cash amount (including by check representing readily available funds or a wire transfer); or

| (v) | any other arrangement approved by the Committee and permitted under applicable law;

all under such rules as may be established by the Committee and in compliance with the Company’s Insider Trading Policy and 10b5-1 Trading Plan Policy, if applicable; provided however, that if Participant is a Section 16 officer of the Company under the Exchange Act, then unless determined otherwise by the Committee in advance of a Tax-Related Items withholding event, the method of withholding for this PSU will be (ii) above.

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Depending on the withholding method, the Company may withhold or account for Tax-Related Items by considering applicable statutory withholding rates or other applicable withholding rates, including up to the maximum permissible statutory rate for Participant’s tax jurisdiction(s) in which case Participant will have no entitlement to the equivalent amount in Shares and may receive a refund of any over-withheld amount in cash in accordance with applicable law. If the obligation for Tax-Related Items is satisfied by withholding in Shares, for tax purposes, Participant is deemed to have been issued the full number of Shares subject to the vested PSUs, notwithstanding that a number of the Shares are held back solely for the purpose of satisfying the withholding obligation for Tax-Related Items.

Finally, Participant agrees to pay to the Company or the Employer any amount of Tax-Related Items that the Company or the Employer may be required to withhold or account for as a result of Participant’s participation in the Plan that cannot be satisfied by the means previously described. The Company may refuse to issue or deliver the Shares or the proceeds of the sale of Shares, if Participant fails to comply with Participant’s obligations in connection with the Tax-Related Items.

7. Nature of Grant. By accepting the PSUs, Participant acknowledges, understands and agrees that:

(a) the Plan is established voluntarily by the Company, it is discretionary in nature and it may be modified, amended, suspended or terminated by the Company at any time, to the extent permitted by the Plan;

(b) the grant of the PSUs is exceptional, voluntary and occasional and does not create any contractual or other right to receive future grants of PSUs, or benefits in lieu of PSUs, even if PSUs have been granted in the past;

(c) all decisions with respect to future PSUs or other grants, if any, will be at the sole discretion of the Company;

(d) Participant is voluntarily participating in the Plan;

(e) the PSUs and Participant’s participation in the Plan will not create a right to employment or be interpreted as forming or amending an employment or service contract with the Company, the Employer or any Parent, Subsidiary or Affiliate and shall not interfere with the ability of the Company, the Employer or any Parent, Subsidiary or Affiliate, as applicable, to terminate Participant’s employment or service relationship (if any);

(f) the PSUs and the Shares subject to the PSUs, and the income from and value of same, are not intended to replace any pension rights or compensation;

(g) the PSUs and the Shares subject to the PSUs, and the income from and value of same, are not part of normal or expected compensation for any purpose, including, but not limited to, calculating any severance, resignation, termination, redundancy, dismissal, end-of-service payments, bonuses, long-service awards, pension or retirement or welfare benefits or similar payments;

(h) unless otherwise agreed with the Company, the PSUs and the Shares subject to the PSUs, and the income from and value of same, are not granted as consideration for, or in connection with, the service Participant may provide as a director of a Parent, Subsidiary or Affiliate;

(i) the future value of the underlying Shares is unknown, indeterminable and cannot be predicted with certainty;

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(j) no claim or entitlement to compensation or damages will arise from forfeiture of the PSUs resulting from Participant’s termination of Service (regardless of the reason for such termination and whether or not later found to be invalid or in breach of employment laws in the jurisdiction where Participant is employed or the terms of Participant’s employment agreement, if any); and

(k) neither the Company, the Employer nor any Parent, Subsidiary or Affiliate will be liable for any foreign exchange rate fluctuation between Participant’s local currency and the United States Dollar that may affect the value of the PSUs or of any amounts due to Participant pursuant to the settlement of the PSUs or the subsequent sale of any Shares acquired upon settlement.

8. No Advice Regarding Grant. The Company is not providing any tax, legal or financial advice, nor is the Company making any recommendations regarding Participant’s participation in the Plan, or Participant’s acquisition or sale of the underlying Shares. Participant acknowledges, understands and agrees he or she should consult with his or her own personal tax, legal and financial advisors regarding his or her participation in the Plan before taking any action related to the Plan.

9. Data Privacy. Participant hereby explicitly and unambiguously consents to the collection, use and transfer, in electronic or other form, of Participant’s personal data as described in this Agreement and any other PSU grant materials by and among, as applicable, the Employer, the Company and any Parent, Subsidiary or Affiliate for the exclusive purpose of implementing, administering and managing Participant’s participation in the Plan.

Participant understands that the Company and the Employer may hold certain personal information about Participant, including, but not limited to, Participant’s name, home address, email address and telephone number, date of birth, social insurance number, passport number or other identification number (e.g., resident registration number), salary, nationality, job title, any shares of stock or directorships held in the Company, details of all PSUs or any other entitlement to shares of stock awarded, canceled, exercised, vested, unvested or outstanding in Participant’s favor (“Data”), for the exclusive purpose of implementing, administering and managing the Plan.

Participant understands that Data will be transferred to E*TRADE Financial Services, Solium-Shareworks, or other third party (“Online Administrator”) and its affiliated companies or such other stock plan service provider as may be designated by the Company from time to time, which is assisting the Company with the implementation, administration and management of the Plan. Participant understands that the recipients of Data may be located in the United States or elsewhere, and that the recipients’ country may have different data privacy laws and protections than Participant’s country. Participant understands that if he or she resides outside the United States, he or she may request a list with the names and addresses of any potential recipients of Data by contacting his or her local human resources representative. Participant authorizes the Company, [Online Administrator], or such other stock plan service provider as may be designated by the Company from time to time, and any other possible recipients which may assist the Company (presently or in the future) with implementing, administering and managing the Plan to receive, possess, use, retain and transfer Data, in electronic or other form, for the sole purpose of implementing, administering and managing his or her participation in the Plan. Participant understands that Data will be held only as long as is necessary to implement, administer and manage Participant’s participation in the Plan. Participant understands if he or she resides outside the United States, he or she may, at any time, view Data, request information about the storage and processing of Data, require any necessary amendments to Data or refuse or withdraw the consents herein, in any case without cost, by contacting his or her local human resources representative. Further, Participant understands that he or she is providing the consents herein on a purely voluntary basis. If Participant does not consent, or if Participant later seeks to revoke his or her consent, his or her employment status or service with the

48

Employer will not be affected; the only consequence of refusing or withdrawing Participant’s consent is that the Company would not be able to grant PSUs or other equity awards to Participant or administer or maintain such awards. Therefore, Participant understands that refusing or withdrawing his or her consent may affect Participant’s ability to participate in the Plan. For more information on the consequences of Participant’s refusal to consent or withdrawal of consent, Participant understands that he or she may contact his or her local human resources representative.

Finally, upon request of the Company or the Employer, Participant agrees to provide an executed data privacy consent form (or any other agreements or consents) that the Company or the Employer may deem necessary to obtain from Participant for the purpose of administering Participant’s participation in the Plan in compliance with the data privacy laws in Participant’s country, either now or in the future. Participant understands and agrees that Participant will not be able to participate in the Plan if Participant fails to provide any such consent or agreement requested by the Company and/or the Employer.

10. Language. Participant acknowledges that he or she is sufficiently proficient in English to understand the terms and conditions of this Agreement. Furthermore, if Participant has received this Agreement or any other document related to the PSU and/or the Plan translated into a language other than English and if the meaning of the translated version is different than the English version, the English version will control.

11. Appendix. Notwithstanding any provisions in this Agreement, the PSUs will be subject to any special terms and conditions set forth in any appendix to this Agreement for Participant’s country. Moreover, if Participant relocates to one of the countries included in the Appendix, the special terms and conditions for such country will apply to Participant, to the extent the Company determines that the application of such terms and conditions is necessary or advisable for legal or administrative reasons. The Appendix constitutes part of this Agreement.

12. Imposition of Other Requirements. The Company reserves the right to impose other requirements on Participant’s participation in the Plan, on the PSUs and on any Shares acquired under the Plan, to the extent the Company determines it is necessary or advisable for legal or administrative reasons, and to require Participant to sign any additional agreements or undertakings that may be necessary to accomplish the foregoing.

13. Acknowledgement. The Company and Participant agree that the PSUs are granted under and governed by the Notice, this Agreement and the provisions of the Plan (incorporated herein by reference). Participant: (a) acknowledges receipt of a copy of the Plan and the Plan prospectus, (b) represents that Participant has carefully read and is familiar with their provisions, and (c) hereby accepts the PSUs subject to all of the terms and conditions set forth herein and those set forth in the Plan and the Notice.

14. Entire Agreement; Enforcement of Rights. This Agreement, the Plan and the Notice constitute the entire agreement and understanding of the parties relating to the subject matter herein and supersede all prior discussions between them. Any prior agreements, commitments or negotiations concerning the purchase of the Shares hereunder are superseded. No adverse modification of or adverse amendment to this Agreement, nor any waiver of any rights under this Agreement, will be effective unless in writing and signed by the parties to this Agreement (which writing and signing may be electronic). The failure by either party to enforce any rights under this Agreement will not be construed as a waiver of any rights of such party.

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15. Compliance with Laws and Regulations. The issuance of Shares will be subject to and conditioned upon compliance by the Company and Participant with all applicable state, federal and foreign laws and regulations and with all applicable requirements of any stock exchange or automated quotation system on which the Company’s Shares may be listed or quoted at the time of such issuance or transfer. Participant understands that the Company is under no obligation to register or qualify the Shares with any state, federal or foreign securities commission or to seek approval or clearance from any governmental authority for the issuance or sale of the Shares. Further, Participant agrees that the Company shall have unilateral authority to amend the Plan and this PSU Agreement without Participant’s consent to the extent necessary to comply with securities or other laws applicable to issuance of Shares. Finally, the Shares issued pursuant to this PSU Agreement shall be endorsed with appropriate legends, if any, determined by the Company.

16. Severability. If one or more provisions of this Agreement are held to be unenforceable under applicable law, then such provision will be enforced to the maximum extent possible given the intent of the parties hereto. If such clause or provision cannot be so enforced, then (a) such provision will be excluded from this Agreement, (b) the balance of this Agreement will be interpreted as if such provision were so excluded and (c) the balance of this Agreement will be enforceable in accordance with its terms.

17. Governing Law and Venue. This Agreement and all acts and transactions pursuant hereto and the rights and obligations of the parties hereto will be governed, construed and interpreted in accordance with the laws of the State of Delaware, without giving effect to such state’s conflict of laws rules.

Any and all disputes relating to, concerning or arising from this Agreement, or relating to, concerning or arising from the relationship between the parties evidenced by the Plan or this Agreement, will be brought and heard exclusively in the United States District Court for the District of Northern California or the Superior Court of California, County of San Mateo. Each of the parties hereby represents and agrees that such party is subject to the personal jurisdiction of said courts; hereby irrevocably consents to the jurisdiction of such courts in any legal or equitable proceedings related to, concerning or arising from such dispute, and waives, to the fullest extent permitted by law, any objection which such party may now or hereafter have that the laying of the venue of any legal or equitable proceedings related to, concerning or arising from such dispute which is brought in such courts is improper or that such proceedings have been brought in an inconvenient forum.

18. No Rights as Employee, Director or Consultant. Nothing in this Agreement will affect in any manner whatsoever any right or power of the Company, or a Parent, Subsidiary or Affiliate, to terminate Participant’s Service, for any reason, with or without Cause.

19. Consent to Electronic Delivery of All Plan Documents and Disclosures. By Participant’s acceptance of the Notice (whether in writing or electronically), Participant and the Company agree that the PSUs are granted under and governed by the terms and conditions of the Plan, the Notice and this Agreement. Participant has reviewed the Plan, the Notice and this Agreement in their entirety, has had an opportunity to obtain the advice of counsel prior to executing this Notice and Agreement, and fully understands all provisions of the Plan, the Notice and this Agreement. Participant hereby agrees to accept as binding, conclusive and final all decisions or interpretations of the Committee upon any questions relating to the Plan, the Notice and this Agreement. Participant further agrees to notify the Company upon any change in Participant’s residence address. By acceptance of the PSUs, Participant agrees to participate in the Plan through an on-line or electronic system established and maintained by the Company or a third party designated by the Company and consents to the electronic delivery of the Notice, this Agreement, the Plan, account statements, Plan prospectuses required by the SEC, U.S. financial reports of the Company, and all other documents that the Company is required to deliver to its security holders (including, without limitation, annual reports and proxy statements) or other

50

communications or information related to the PSUs and current or future participation in the Plan. Electronic delivery may include the delivery of a link to the Company intranet or the internet site of a third party involved in administering the Plan, the delivery of the document via e-mail or such other delivery determined at the Company’s discretion. Participant acknowledges that Participant may receive from the Company a paper copy of any documents delivered electronically at no cost if Participant contacts the Company by telephone, through a postal service or electronic mail to Stock Administration. Participant further acknowledges that Participant will be provided with a paper copy of any documents delivered electronically if electronic delivery fails; similarly, Participant understands that Participant must provide on request to the Company or any designated third party a paper copy of any documents delivered electronically if electronic delivery fails. Also, Participant understands that Participant’s consent may be revoked or changed, including any change in the electronic mail address to which documents are delivered (if Participant has provided an electronic mail address), at any time by notifying the Company of such revised or revoked consent by telephone, postal service or electronic mail to Stock Administration.

20. Insider Trading Restrictions/Market Abuse Laws. Participant acknowledges that, depending on Participant’s country of residence, the broker’s country, or the country in which the Shares are listed, Participant may be subject to insider trading restrictions and/or market abuse laws in applicable jurisdictions, which may affect Participant’s ability to directly or indirectly, accept, acquire, sell or attempt to sell or otherwise dispose of Shares, or rights to Shares (e.g., PSUs), or rights linked to the value of Shares, during such times as Participant is considered to have “inside information” regarding the Company (as defined by the laws or regulations in the applicable jurisdiction). Local insider trading laws and regulations may prohibit the cancellation or amendment of orders Participant placed before possessing the inside information. Furthermore, Participant may be prohibited from (i) disclosing the inside information to any third party, including fellow employees (other than on a “need to know” basis) and (ii) “tipping” third parties or causing them to otherwise buy or sell securities. Any restrictions under these laws or regulations are separate from and in addition to any restrictions that may be imposed under any applicable Company insider trading policy. Participant acknowledges that it is Participant’s responsibility to comply with any applicable restrictions and understands that Participant should consult his or her personal legal advisor on such matters. In addition, Participant acknowledges that he or she read the Company’s Insider Trading Policy, and agrees to comply with such policy, as it may be amended from time to time, whenever Participant acquires or disposes of the Company’s securities.

21. Foreign Asset/Account, Exchange Control and Tax Reporting. Participant may be subject to foreign asset/account, exchange control and/or tax reporting requirements as a result of the acquisition, holding and/or transfer of Shares or cash resulting from his or her participation in the Plan. Participant may be required to report such accounts, assets, the balances therein, the value thereof and/or the transactions related thereto to the applicable authorities in Participant’s country and/or repatriate funds received in connection with the Plan within certain time limits or according to specified procedures. Participant acknowledges that he or she is responsible for ensuring compliance with any applicable foreign asset/account, exchange control and tax reporting requirements and should consult his or her personal legal and tax advisors on such matters.

22. Code Section 409A. For purposes of this Agreement, a termination of employment will be determined consistent with the rules relating to a “separation from service” as defined in Section 409A of the Internal Revenue Code and the regulations thereunder (“Section 409A”). Notwithstanding anything else provided herein, to the extent any payments provided under this PSU Agreement in connection with Participant’s termination of employment constitute deferred compensation subject to Section 409A, and Participant is deemed at the time of such termination of employment to be a “specified employee” under Section 409A, then such payment shall not be made or commence until the earlier of (i) the expiration of the six-month period measured from Participant’s separation from service from the Company or (ii) the

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date of Participant’s death following such a separation from service; provided, however, that such deferral shall only be effected to the extent required to avoid adverse tax treatment to Participant including, without limitation, the additional tax for which Participant would otherwise be liable under Section 409A(a)(1)(B) in the absence of such a deferral. To the extent any payment under this PSU Agreement may be classified as a “short-term deferral” within the meaning of Section 409A, such payment shall be deemed a short-term deferral, even if it may also qualify for an exemption from Section 409A under another provision of Section 409A. Payments pursuant to this section are intended to constitute separate payments for purposes of Section 1.409A-2(b)(2) of the Treasury Regulations.

23. Award Subject to Company Clawback or Recoupment. The PSUs shall be subject to clawback or recoupment pursuant to any compensation clawback or recoupment policy adopted by the Board or required by law during the term of Participant’s employment or other Service that is applicable to Participant. In addition to any other remedies available under such policy, applicable law may require the cancellation of Participant’s PSUs (whether vested or unvested) and the recoupment of any gains realized with respect to Participant’s PSUs.

BY ACCEPTING THIS AWARD OF PSUS, PARTICIPANT AGREES TO ALL OF THE TERMS AND CONDITIONS DESCRIBED ABOVE AND IN THE PLAN.

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APPENDIX

SUTRO BIOPHARMA, INC.

2018 EQUITY INCENTIVE PLAN

GLOBAL PERFORMANCE STOCK UNIT AWARD AGREEMENT

COUNTRY SPECIFIC PROVISIONS FOR EMPLOYEES OUTSIDE THE U.S.

Terms and Conditions

This Appendix includes additional terms and conditions that govern the PSUs granted to Participant under the Plan if Participant resides and/or works in one of the countries below. This Appendix forms part of the Agreement. Any capitalized term used in this Appendix without definition will have the meaning ascribed to it in the Notice, the Agreement or the Plan, as applicable.

If Participant is a citizen or resident of a country, or is considered resident of a country, other than the one in which Participant is currently working, or Participant transfers employment and/or residency between countries after the Date of Grant, the Company will, in its sole discretion, determine to what extent the additional terms and conditions included herein will apply to Participant under these circumstances.

Notifications

This Appendix also includes information relating to exchange control, securities laws, foreign asset/account reporting and other issues of which Participant should be aware with respect to Participant’s participation in the Plan. The information is based on the securities, exchange control, foreign asset/account reporting and other laws in effect in the respective countries as of September, 2018. Such laws are complex and change frequently. As a result, Participant should not rely on the information herein as the only source of information relating to the consequences of Participant’s participation in the Plan because the information may be out of date at the time that Participant vests in the PSUs, sells Shares acquired under the Plan or takes any other action in connection with the Plan.

In addition, the information is general in nature and may not apply to Participant’s particular situation, and the Company is not in a position to assure Participant of any particular result. Accordingly, Participant should seek appropriate professional advice as to how the relevant laws in Participant’s country may apply to Participant’s situation.

Finally, if Participant is a citizen or resident of a country, or is considered resident of a country, other than the one in which Participant is currently working and/or residing, or Participant transfers employment and/or residency after the Date of Grant, the information contained herein may not apply to Participant in the same manner.

None.

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