
<PAGE>   1

                                                                    Exhibit 4(g)


================================================================================




                               GUARANTEE AGREEMENT


                                     between


                                    KEYCORP,
                                  as Guarantor,


                                       and


                             BANKERS TRUST COMPANY,
                              as Guarantee Trustee


                      -------------------------------------

                         KEYCORP INSTITUTIONAL CAPITAL B
                      -------------------------------------



                               Dated as of           , 1997


================================================================================



<PAGE>   2



                         KEYCORP INSTITUTIONAL CAPITAL B

            Certain Sections of this Guarantee Agreement relating to
                         Sections 310 through 318 of the
                          Trust Indenture Act of 1939:

<TABLE>
<CAPTION>
     Section of                                                                     Section of
Trust Indenture Act                                                                     Guarantee Agreement
-------------------                                                                     -------------------
<S>                                                                                           <C>    
310(a)..........................................................................................4.1(a)
    (b).........................................................................................4.1(c), 2.8
    (c).........................................................................................Inapplicable
311(a)..........................................................................................2.2(b)
    (b).........................................................................................2.2(b)
    (c).........................................................................................Inapplicable
312(a)..........................................................................................2.2(a)
    (b).........................................................................................2.2(b)
313.............................................................................................2.3
314(a)..........................................................................................2.4
    (b).........................................................................................Inapplicable
    (c).........................................................................................2.5
    (d).........................................................................................Inapplicable
    (e).........................................................................................1.1, 2.5, 3.2
    (f).........................................................................................2.1, 3.2
315(a)..........................................................................................3.1(d)
    (b).........................................................................................2.7
    (c).........................................................................................3.1(c)
    (d).........................................................................................3.1(d)
316(a)..........................................................................................1.1, 2.6, 5.4
    (b).........................................................................................5.3, 5.7
    (c).........................................................................................8.2
317(a)..........................................................................................Inapplicable
    (b).........................................................................................Inapplicable
318(a)..........................................................................................2.1(b)
    (b).........................................................................................2.1
    (c).........................................................................................2.1(a)

-----------
<FN>
Note: This reconciliation and tie sheet shall not, for any purpose, be deemed to
      be a part of the Guarantee Agreement.
</TABLE>

                                        i

<PAGE>   3



                                TABLE OF CONTENTS


                                    ARTICLE I

                                   DEFINITIONS

<TABLE>
<CAPTION>
<S>          <C>                                                                                                 <C>
SECTION 1.1. Interpretation.....................................................................................  2
SECTION 1.2. Definitions........................................................................................  2

                                   ARTICLE II

                               TRUST INDENTURE ACT

SECTION 2.1. Trust Indenture Act; Application...................................................................  6
SECTION 2.2. List of Holders....................................................................................  6
SECTION 2.3. Reports by the Guarantee Trustee...................................................................  6
SECTION 2.4. Periodic Reports to Guarantee Trustee..............................................................  7
SECTION 2.5. Evidence of Compliance with Conditions Precedent...................................................  7
SECTION 2.6. Events of Default; Waiver..........................................................................  7
SECTION 2.7. Event of Default; Notice...........................................................................  7
SECTION 2.8. Conflicting Interests..............................................................................  8

                                   ARTICLE III

               POWERS, DUTIES AND RIGHTS OF THE GUARANTEE TRUSTEE

SECTION 3.1. Powers and Duties of the Guarantee Trustee.........................................................  8
SECTION 3.2. Certain Rights of Guarantee Trustee................................................................  9
SECTION 3.3. Compensation; Indemnity; Fees...................................................................... 11

                                   ARTICLE IV

                                GUARANTEE TRUSTEE

SECTION 4.1. Guarantee Trustee; Eligibility..................................................................... 12
SECTION 4.2. Appointment, Removal and Resignation of the Guarantee Trust........................................ 12
</TABLE>


                                       ii

<PAGE>   4



                                    ARTICLE V

                                    GUARANTEE

<TABLE>
<CAPTION>
<S>          <C>                                                                                                 <C>
SECTION 5.1. Guarantee.......................................................................................... 13
SECTION 5.2. Waiver of Notice and Demand........................................................................ 13
SECTION 5.3. Obligations Not Affected........................................................................... 13
SECTION 5.4. Rights of Holders.................................................................................. 14
SECTION 5.5. Guarantee of Payment............................................................................... 15
SECTION 5.6. Subrogation........................................................................................ 15
SECTION 5.7. Independent Obligations............................................................................ 15

                                   ARTICLE VI

                           COVENANTS AND SUBORDINATION

SECTION 6.1. Subordination...................................................................................... 15
SECTION 6.2. Pari Passu Guarantees.............................................................................. 16

                                   ARTICLE VII

                                   TERMINATION

SECTION 7.1. Termination........................................................................................ 16

                                  ARTICLE VIII

                                  MISCELLANEOUS

SECTION 8.1. Successors and Assigns............................................................................. 16
SECTION 8.2. Amendments......................................................................................... 16
SECTION 8.3. Notices............................................................................................ 17
SECTION 8.4. Benefit............................................................................................ 18
SECTION 8.5. Governing Law...................................................................................... 18
SECTION 8.6. Counterparts....................................................................................... 18
</TABLE>


                                       iii

<PAGE>   5





         GUARANTEE AGREEMENT, dated as of ________ , 1997 is executed and
delivered by KEYCORP, an Ohio corporation (the "Guarantor") having its principal
office at 127 Public Square, Cleveland, Ohio 44114-1306, and BANKERS TRUST
COMPANY, a banking corporation organized under the laws of the State of New
York, as trustee (the "Guarantee Trustee"), for the benefit of the Holders (as
defined herein) from time to time of the Capital Securities (as defined herein)
of KEYCORP INSTITUTIONAL CAPITAL B, a Delaware statutory business trust (the
"Issuer Trust").

                              W I T N E S S E T H :

         WHEREAS, pursuant to an Amended and Restated Trust Agreement, dated as
of December 30, 1996 (the "Trust Agreement"), among the Guarantor, as Depositor,
the Property Trustee and the Delaware Trustee named therein and the Holders from
time to time of undivided beneficial interests in the assets of the Issuer
Trust, the Issuer Trust issued $150,000,000 aggregate Liquidation Amount (as
defined in the Trust Agreement) of its 8.25% Capital Securities, Liquidation
Amount $1,000 per Capital Security (the "Old Capital Securities"), representing
preferred undivided beneficial interests in the assets of the Issuer Trust and
having the terms set forth in the Trust Agreement;

         WHEREAS, the Old Capital Securities were issued by the Issuer Trust and
the proceeds thereof, together with the proceeds from the issuance of the Issuer
Trust's Common Securities (as defined below), were used to purchase the Junior
Subordinated Debentures (as defined herein) of the Guarantor which were
deposited with Bankers Trust Company, as Property Trustee under the Trust
Agreement, as trust assets;

         WHEREAS, as an incentive for the Holders to purchase the Old Capital
Securities, the Guarantor irrevocably and unconditionally agreed, to the extent
set forth in the Guarantee Agreement dated as of December 30, 1996 among the
Guarantor and the Guarantee Trustee, for the benefit of the Holders of the Old
Capital Securities (the "Old Guarantee"), to pay to the Holders of the Old
Capital Securities the Guarantee Payments set forth therein;

         WHEREAS, pursuant to the Registration Rights Agreement, dated as of
December 30, 1996 among the Guarantor, the Issuer Trust and the Initial
Purchaser named therein (the "Registration Rights Agreement"), the Guarantor and
the Issuer Trust agreed to file a registration statement (the "Registration
Statement") to exchange, inter alia, the Old Capital Securities for a like
amount of new capital securities (the "New Capital Securities", and together
with the Old Capital Securities, the "Capital Securities") and the Old Guarantee
for the Guarantee (as defined herein) for the benefit of the Holders of the
Capital Securities;

         WHEREAS, the Guarantee will be substantially identical to the Old
Guarantee except that the Guarantee will be registered pursuant to an effective
registration statement under the Securities Act of 1933, as amended (the
"Securities Act"), and the Guarantee will not contain provisions restricting
transfer in the absence of registration under the Securities Act;


<PAGE>   6




         NOW, THEREFORE, in consideration of the purchase or retention by each
Holder of Capital Securities, which purchase or retention the Guarantor hereby
agrees shall benefit the Guarantor, the Guarantor executes and delivers this
Guarantee Agreement to provide as follows for the benefit of the Holders from
time to time of the Capital Securities:


                                    ARTICLE I

                         INTERPRETATION AND DEFINITIONS

         SECTION 1.1. Interpretation.

         In this Guarantee Agreement, unless the context otherwise requires:

                  (a) capitalized terms used in this Guarantee Agreement but not
         defined in the preamble hereto have the respective meanings assigned to
         them in Section 1.2;

                  (b) a term defined anywhere in this Guarantee Agreement has
         the same meaning throughout;

                  (c) all references to "the Guarantee Agreement" or "this
         Guarantee Agreement" are to this Guarantee Agreement as modified,
         supplemented or amended from time to time;

                  (d) all references in this Guarantee Agreement to Articles and
         Sections are to Articles and Sections of this Guarantee Agreement
         unless otherwise specified;

                  (e) a term defined in the Trust Indenture Act has the same
         meaning when used in this Guarantee Agreement unless otherwise defined
         in this Guarantee Agreement or unless the context otherwise requires;

                  (f) a reference to the singular includes the plural and
         vice-versa; and

                  (g) the masculine, feminine or neuter genders used herein
         shall include the masculine, feminine and neuter genders.

         SECTION 1.2. Definitions.

         As used in this Guarantee Agreement, the terms set forth below shall,
unless the context otherwise requires, have the following meanings:

                  "Allocable Amounts", when used with respect to any Senior
         Subordinated Debt, means the amount necessary to pay all principal of
         (and premium, if any) and interest, if any,

                                       2


<PAGE>   7




         on such Senior Subordinated Debt in full less, if applicable, any
         portion of such amounts which would have been paid to, and retained by,
         the holders of such Senior Subordinated Debt (whether as a result of
         the receipt of payments by the holders of such Senior Subordinated Debt
         from the Guarantor or any other obligor thereon or from any holders of,
         or trustee in respect of, other indebtedness that is subordinate and
         junior in right of payment to such Senior Subordinated Debt pursuant to
         any provision of such indebtedness for the payment over of amounts
         received on account of such indebtedness to the holders of such Senior
         Subordinated Debt) but for the fact that such Senior Subordinated Debt
         is subordinate or junior in right of payment to trade accounts payable
         or accrued liabilities arising in the ordinary course of business.

                  "Affiliate" of any specified Person means any other Person
         directly or indirectly controlling or controlled by or under direct or
         indirect common control with such specified Person; provided, however,
         that the Issuer Trust shall not be deemed to be an Affiliate of the
         Guarantor. For the purposes of this definition, "control", when used
         with respect to any specified Person, means the power to direct the
         management and policies of such Person, directly or indirectly, whether
         through the ownership of voting securities, by contract or otherwise;
         and the terms "controlling" and "controlled" have meanings correlative
         to the foregoing.

                  "Board of Directors" means either the board of directors of
         the Guarantor or any committee of that board duly authorized to act
         hereunder.

                  "Common Securities" means the securities representing common
         undivided beneficial interests in the assets of the Issuer Trust.

                  "Event of Default" means a default by the Guarantor on any of
         its payment or other obligations under this Guarantee Agreement;
         provided, however, that, except with respect to a default in payment of
         any Guarantee Payments, the Guarantor shall have received notice of
         default and shall not have cured such default within 30 days after
         receipt of such notice.

                  "Guarantee Payments" means the following payments or
         distributions, without duplication, with respect to the Capital
         Securities, to the extent not paid or made by or on behalf of the
         Issuer Trust: (i) any accumulated and unpaid Distributions (as defined
         in the Trust Agreement) required to be paid on the Capital Securities,
         to the extent the Issuer Trust shall have funds on hand available
         therefor at such time, (ii) the redemption price, including all
         accumulated and unpaid Distributions to the date of redemption (the
         "Redemption Price"), with respect to any Capital Securities called for
         redemption by the Issuer Trust, to the extent the Issuer Trust shall
         have funds on hand available therefor at such time, and (iii) upon a
         voluntary or involuntary termination, winding up or liquidation of the
         Issuer Trust, unless Junior Subordinated Debentures are distributed to
         the Holders, the lesser of (a) the aggregate of the Liquidation Amount
         of $1,000 per Capital Security plus accumulated and unpaid 


                                       3
<PAGE>   8



         Distributions on the Capital Securities to the date of payment to the
         extent that the Issuer Trust shall have funds available therefor at
         such time and (b) the amount of assets of the Issuer Trust remaining
         available for distribution to Holders in liquidation of the Issuer
         Trust (in either case, the "Liquidation Distribution").

                  "Guarantee Trustee" means Bankers Trust Company, until a
         Successor Guarantee Trustee has been appointed and has accepted such
         appointment pursuant to the terms of this Guarantee Agreement, and
         thereafter means each such Successor Guarantee Trustee.

                  "Holder" means any holder, as registered on the books and
         records of the Issuer Trust, of any Capital Securities; provided,
         however, that in determining whether the holders of the requisite
         percentage of Capital Securities have given any request, notice,
         consent or waiver hereunder, "Holder" shall not include the Guarantor,
         the Guarantee Trustee, or any Affiliate of the Guarantor or the
         Guarantee Trustee.

                  "Indenture" means the Indenture dated as of December 4, 1996,
         as supplemented and amended between the Guarantor and Bankers Trust
         Company, as trustee.

                  "Junior Subordinated Debentures" means the 8.25% Junior
         Subordinated Debentures issued by the Guarantor pursuant to the
         Indenture.

                  "List of Holders" has the meaning specified in Section 2.2(a).

                  "Majority in Liquidation Amount of the Capital Securities"
         means, except as provided by the Trust Indenture Act, a vote by the
         Holder(s), voting separately as a class, of more than 50% of the
         Liquidation Amount of all then outstanding Capital Securities issued by
         the Issuer Trust.

                  "Officers' Certificate" means, with respect to any Person, a
         certificate signed by the Chairman or a Vice Chairman of the Board of
         Directors of such Person or the President or a Vice President of such
         Person, and by the Treasurer, an Assistant Treasurer, the Secretary or
         an Assistant Secretary of such Person, and delivered to the Guarantee
         Trustee. Any Officers' Certificate delivered with respect to compliance
         with a condition or covenant provided for in this Guarantee Agreement
         shall include:

                           (a) a statement that each officer signing the
                  Officers' Certificate has read the covenant or condition and
                  the definitions relating thereto;

                           (b) a brief statement of the nature and scope of the
                  examination or investigation undertaken by each officer in
                  rendering the Officers' Certificate;

                           (c) a statement that each officer has made such
                  examination or investigation as, in such officer's opinion, is
                  necessary to enable such officer to express an informed
                  opinion as to whether or not such covenant or condition has
                  been complied with; and


                                       4
<PAGE>   9




                           (d) a statement as to whether, in the opinion of each
                  officer, such condition or covenant has been complied with.

                  "Person" means a legal person, including any individual,
         corporation, estate, partnership, joint venture, association, joint
         stock company, limited liability company, trust, unincorporated
         association, or government or any agency or political subdivision
         thereof, or any other entity of whatever nature.

                  "Responsible Officer" means, with respect to the Guarantee
         Trustee, any Senior Vice President, any Vice President, any Assistant
         Vice President, the Secretary, any Assistant Secretary, the Treasurer,
         any Assistant Treasurer, any Trust Officer or Assistant Trust Officer
         or any other officer of the Corporate Trust Department of the Guarantee
         Trustee and also means, with respect to a particular corporate trust
         matter, any other officer to whom such matter is referred because of
         that officer's knowledge of and familiarity with the particular
         subject.

                  "Senior Debt" means any obligation of the Guarantor to its
         creditors, whether now outstanding or subsequently incurred, other than
         any obligation as to which, in the instrument creating or evidencing
         the obligation or pursuant to which the obligation is outstanding, it
         is provided that such obligation is not Senior Debt. Senior Debt does
         not include Senior Subordinated Debt or the Junior Subordinated
         Debentures.

                  "Senior Indebtedness" means (i) Senior Debt (but excluding
         trade accounts payable and accrued liabilities arising in the ordinary
         course of business) and (ii) the Allocable Amounts of Senior
         Subordinated Debt.

                  "Senior Subordinated Debt" means any obligation of the
         Guarantor to its creditors, whether now outstanding or subsequently
         incurred, where the instrument creating or evidencing the obligation or
         pursuant to which the obligation is outstanding, provides that it is
         subordinate and junior in right of payment to Senior Debt. Senior
         Subordinated Debt includes the Guarantor's outstanding subordinated
         debt securities and any subordinated debt securities issued in the
         future with substantially similar subordination terms and does not
         include the Junior Subordinated Debentures or any subordinated debt
         securities issued in the future or the past with substantially similar
         subordination terms.

                  "Successor Guarantee Trustee" means a successor Guarantee
         Trustee possessing the qualifications to act as Guarantee Trustee under
         Section 4.1.

                  "Trust Indenture Act" means the Trust Indenture Act of 1939, 
         as amended.

Capitalized or otherwise defined terms used but not otherwise defined herein
shall have the meanings assigned to such terms in the Trust Agreement as in
effect on the date hereof.


                                       5
<PAGE>   10




                                   ARTICLE II

                               TRUST INDENTURE ACT
         SECTION 2.1. Trust Indenture Act; Application.

         (a) This Guarantee Agreement is subject to the provisions of the Trust
Indenture Act that are required to be part of this Guarantee Agreement and
shall, to the extent applicable, be governed by such provisions.

         (b) If and to the extent that any provision of this Guarantee Agreement
limits, qualifies or conflicts with the duties imposed by Sections 310 to 317,
inclusive, of the Trust Indenture Act, such imposed duties shall control.

         SECTION 2.2. List of Holders.

         (a) The Guarantor shall furnish or cause to be furnished to the
Guarantee Trustee (a) semiannually, on or before June 15 and December 15 of each
year, a list, in such form as the Guarantee Trustee may reasonably require, of
the names and addresses of the Holders (the "List of Holders") as of a date not
more than 15 days prior to the delivery thereof, and (b) at such other times as
the Guarantee Trustee may request in writing, within 30 days after the receipt
by the Guarantor of any such request, a List of Holders as of a date not more
than 15 days prior to the time such list is furnished, in each case to the
extent such information is in the possession or control of the Guarantor and is
not identical to a previously supplied list of Holders or has not otherwise been
received by the Guarantee Trustee in its capacity as such. The Guarantee Trustee
may destroy any List of Holders previously given to it on receipt of a new List
of Holders.

         (b) The Guarantee Trustee shall comply with its obligations under
Section 311(a), Section 311(b) and Section 312(b) of the Trust Indenture Act.

         SECTION 2.3. Reports by the Guarantee Trustee.

         Not later than May 31 of each year, commencing May 31, 1997, the
Guarantee Trustee shall provide to the Holders such reports as are required by
Section 313 of the Trust Indenture Act, if any, in the form and in the manner
provided by Section 313 of the Trust Indenture Act. The Guarantee Trustee shall
also comply with the requirements of Section 313(d) of the Trust Indenture Act.

         SECTION 2.4. Periodic Reports to the Guarantee Trustee.

         The Guarantor shall provide to the Guarantee Trustee, the Securities
and Exchange Commission and the Holders such documents, reports and information,
if any, as required by Section 314 of the Trust Indenture Act and the compliance
certificate required by Section 314 of the Trust 



                                       6
<PAGE>   11




Indenture Act, in the form, in the manner and at the times required by Section
314 of the Trust Indenture Act.

         SECTION 2.5. Evidence of Compliance with Conditions Precedent.

         The Guarantor shall provide to the Guarantee Trustee such evidence of
compliance with such conditions precedent, if any, provided for in this
Guarantee Agreement that relate to any of the matters set forth in Section
314(c) of the Trust Indenture Act. Any certificate or opinion required to be
given by an officer pursuant to Section 314(c)(1) may be given in the form of an
Officers' Certificate.

         SECTION 2.6. Events of Default; Waiver.

         The Holders of a Majority in Liquidation Amount of the Capital
Securities may, by vote, on behalf of the Holders, waive any past Event of
Default and its consequences. Upon such waiver, any such Event of Default shall
cease to exist, and any Event of Default arising therefrom shall be deemed to
have been cured, for every purpose of this Guarantee Agreement, but no such
waiver shall extend to any subsequent or other default or Event of Default or
impair any right consequent therefrom.

         SECTION 2.7. Event of Default; Notice.

         (a) The Guarantee Trustee shall, within 90 days after the occurrence of
an Event of Default, transmit by mail, first class postage prepaid, to the
Holders, notices of all Events of Default known to the Guarantee Trustee, unless
such defaults have been cured before the giving of such notice, provided, that,
except in the case of a default in the payment of a Guarantee Payment, the
Guarantee Trustee shall be protected in withholding such notice if and so long
as the Board of Directors, the executive committee or a trust committee of
directors and/or Responsible Officers of the Guarantee Trustee in good faith
determines that the withholding of such notice is in the interests of the
Holders.

         (b) The Guarantee Trustee shall not be deemed to have knowledge of any
Event of Default unless the Guarantee Trustee shall have received written
notice, or a Responsible Officer charged with the administration of this
Guarantee Agreement shall have obtained written notice, of such Event of
Default.

         SECTION 2.8. Conflicting Interests.

         The Trust Agreement shall be deemed to be specifically described in
this Guarantee Agreement for the purposes of clause (i) of the first proviso
contained in Section 310(b) of the Trust Indenture Act.

                                   ARTICLE III


                                       7
<PAGE>   12





               POWERS, DUTIES AND RIGHTS OF THE GUARANTEE TRUSTEE

         SECTION 3.1. Powers and Duties of the Guarantee Trustee.

         (a) This Guarantee Agreement shall be held by the Guarantee Trustee for
the benefit of the Holders, and the Guarantee Trustee shall not transfer this
Guarantee Agreement to any Person except a Holder exercising his or her rights
pursuant to Section 5.4(iv) or to a Successor Guarantee Trustee on acceptance by
such Successor Guarantee Trustee of its appointment to act as Successor
Guarantee Trustee. The right, title and interest of the Guarantee Trustee shall
automatically vest in any Successor Guarantee Trustee, upon acceptance by such
Successor Guarantee Trustee of its appointment hereunder, and such vesting and
cessation of title shall be effective whether or not conveyancing documents have
been executed and delivered pursuant to the appointment of such Successor
Guarantee Trustee.

         (b) If an Event of Default has occurred and is continuing, the
Guarantee Trustee shall enforce this Guarantee Agreement for the benefit of the
Holders.

         (c) The Guarantee Trustee, before the occurrence of any Event of
Default and after the curing of all Events of Default that may have occurred,
shall undertake to perform only such duties as are specifically set forth in
this Guarantee Agreement, and no implied covenants shall be read into this
Guarantee Agreement against the Guarantee Trustee. In case an Event of Default
has occurred (that has not been cured or waived pursuant to Section 2.6), the
Guarantee Trustee shall exercise such of the rights and powers vested in it by
this Guarantee Agreement, and use the same degree of care and skill in its
exercise thereof, as a prudent person would exercise or use under the
circumstances in the conduct of his or her own affairs.

         (d) No provision of this Guarantee Agreement shall be construed to
relieve the Guarantee Trustee from liability for its own negligent action, its
own negligent failure to act or its own willful misconduct, except that:

                  (i) prior to the occurrence of any Event of Default and after
         the curing or waiving of all such Events of Default that may have
         occurred:

                           (A) the duties and obligations of the Guarantee
                  Trustee shall be determined solely by the express provisions
                  of this Guarantee Agreement, and the Guarantee Trustee shall
                  not be liable except for the performance of such duties and
                  obligations as are specifically set forth in this Guarantee
                  Agreement; and

                           (B) in the absence of bad faith on the part of the
                  Guarantee Trustee, the Guarantee Trustee may conclusively
                  rely, as to the truth of the statements and the correctness of
                  the opinions expressed therein, upon any certificates or
                  opinions furnished to the Guarantee Trustee and conforming to
                  the requirements of this 




                                       8
<PAGE>   13




                  Guarantee Agreement; but in the case of any such certificates
                  or opinions that by any provision hereof or of the Trust
                  Indenture Act are specifically required to be furnished to the
                  Guarantee Trustee, the Guarantee Trustee shall be under a duty
                  to examine the same to determine whether or not they conform
                  to the requirements of this Guarantee Agreement;

                  (ii) the Guarantee Trustee shall not be liable for any error
         of judgment made in good faith by a Responsible Officer of the
         Guarantee Trustee, unless it shall be proved that the Guarantee Trustee
         was negligent in ascertaining the pertinent facts upon which such
         judgment was made;

                  (iii) the Guarantee Trustee shall not be liable with respect
         to any action taken or omitted to be taken by it in good faith in
         accordance with the direction of the Holders of not less than a
         Majority in Liquidation Amount of the Capital Securities relating to
         the time, method and place of conducting any proceeding for any remedy
         available to the Guarantee Trustee, or exercising any trust or power
         conferred upon the Guarantee Trustee under this Guarantee Agreement;
         and

                  (iv) no provision of this Guarantee Agreement shall require
         the Guarantee Trustee to expend or risk its own funds or otherwise
         incur personal financial liability in the performance of any of its
         duties or in the exercise of any of its rights or powers, if the
         Guarantee Trustee shall have reasonable grounds for believing that the
         repayment of such funds or liability is not reasonably assured to it
         under the terms of this Guarantee Agreement or adequate indemnity
         against such risk or liability is not reasonably assured to it.

         SECTION 3.2. Certain Rights of Guarantee Trustee.

         (a) Subject to the provisions of Section 3.1:

                  (i) The Guarantee Trustee may rely and shall be fully
         protected in acting or refraining from acting upon any resolution,
         certificate, statement, instrument, opinion, report, notice, request,
         direction, consent, order, bond, debenture, note, other evidence
         of indebtedness or other paper or document reasonably believed by it to
         be genuine and to have been signed, sent or presented by the proper
         party or parties.

                  (ii) Any direction or act of the Guarantor contemplated by
         this Guarantee Agreement shall be sufficiently evidenced by an
         Officers' Certificate unless otherwise prescribed herein.

                  (iii) Whenever, in the administration of this Guarantee
         Agreement, the Guarantee Trustee shall deem it desirable that a matter
         be proved or established before taking, suffering or omitting to take
         any action hereunder, the Guarantee Trustee (unless other evidence is
         herein specifically prescribed) may, in the absence of bad faith on its
         part, request and rely 




                                       9
<PAGE>   14



         upon an Officers' Certificate which, upon receipt of such request from
         the Guarantee Trustee, shall be promptly delivered by the Guarantor.

                  (iv) The Guarantee Trustee may consult with legal counsel, and
         the written advice or opinion of such legal counsel with respect to
         legal matters shall be full and complete authorization and protection
         in respect of any action taken, suffered or omitted to be taken by it
         hereunder in good faith and in accordance with such advice or opinion.
         Such legal counsel may be legal counsel to the Guarantor or any of its
         Affiliates and may be one of its employees. The Guarantee Trustee shall
         have the right at any time to seek instructions concerning the
         administration of this Guarantee Agreement from any court of competent
         jurisdiction.

                  (v) The Guarantee Trustee shall be under no obligation to
         exercise any of the rights or powers vested in it by this Guarantee
         Agreement at the request or direction of any Holder, unless such Holder
         shall have provided to the Guarantee Trustee such adequate security and
         indemnity as would satisfy a reasonable person in the position of the
         Guarantee Trustee, against the costs, expenses (including attorneys'
         fees and expenses) and liabilities that might be incurred by it in
         complying with such request or direction, including such reasonable
         advances as may be requested by the Guarantee Trustee; provided that,
         nothing contained in this Section 3.2(a)(v) shall be taken to relieve
         the Guarantee Trustee, upon the occurrence of an Event of Default, of
         its obligation to exercise the rights and powers vested in it by this
         Guarantee Agreement.

                  (vi) The Guarantee Trustee shall not be bound to make any
         investigation into the facts or matters stated in any resolution,
         certificate, statement, instrument, opinion, report, notice, request,
         direction, consent, order, bond, debenture, note, other evidence of
         indebtedness or other paper or document, but the Guarantee Trustee, in
         its discretion, may make such further inquiry or investigation into
         such facts or matters as it may see fit.

                  (vii) The Guarantee Trustee may execute any of the trusts or
         powers hereunder or perform any duties hereunder either directly or by
         or through its agents or attorneys, and the Guarantee Trustee shall not
         be responsible for any misconduct or negligence on the part of any such
         agent or attorney appointed with due care by it hereunder.

                  (viii) Whenever in the administration of this Guarantee
         Agreement the Guarantee Trustee shall deem it desirable to receive
         instructions with respect to enforcing any remedy or right or taking
         any other action hereunder, the Guarantee Trustee (A) may request
         instructions from the Holders, (B) may refrain from enforcing such
         remedy or right or taking such other action until such instructions are
         received, and (C) shall be protected in acting in accordance with such
         instructions.



                                       10
<PAGE>   15




         (b) No provision of this Guarantee Agreement shall be deemed to impose
any duty or obligation on the Guarantee Trustee to perform any act or acts or
exercise any right, power, duty or obligation conferred or imposed on it in any
jurisdiction in which it shall be illegal, or in which the Guarantee Trustee
shall be unqualified or incompetent in accordance with applicable law, to
perform any such act or acts or to exercise any such right, power, duty or
obligation. No permissive power or authority available to the Guarantee Trustee
shall be construed to be a duty to act in accordance with such power and
authority.

         SECTION 3.3. Compensation; Indemnity; Fees.

         The Guarantor agrees:

         (a) to pay to the Guarantee Trustee from time to time reasonable
compensation for all services rendered by it hereunder (which compensation shall
not be limited by any provisions of law in regard to the compensation of a
trustee of an express trust);

         (b) except as otherwise expressly provided herein, to reimburse the
Guarantee Trustee upon request for all reasonable expenses, disbursements and
advances incurred or made by the Guarantee Trustee in accordance with any
provision of this Guarantee Agreement (including the reasonable compensation and
the expenses and disbursements of its agents and counsel), except any such
expense, disbursement or advance as may be attributable to its negligence or bad
faith; and

         (c) to indemnify the Guarantee Trustee and its directors, officers,
agents and employees for, and to hold it harmless against, any loss, liability
or expense incurred without negligence or bad faith on the part of the Guarantee
Trustee, arising out of or in connection with the acceptance or administration
of this Guarantee Agreement, including the costs and expenses of defending
itself against any claim or liability in connection with the exercise or
performance of any of its powers or duties hereunder. The Guarantee Trustee will
not claim or exact any lien or charge on any Guarantee Payments as a result of
any amount due to it under this Guarantee Agreement.

         The provisions of this Section 3.3. shall survive the termination of
this Guarantee Agreement or the earlier resignation or removal of the Guarantee
Trustee.


                                   ARTICLE IV

                                GUARANTEE TRUSTEE

         SECTION 4.1. Guarantee Trustee: Eligibility.

         (a) There shall at all times be a Guarantee Trustee which shall:




                                       11
<PAGE>   16



                  (i) not be an Affiliate of the Guarantor; and

                  (ii) be a Person that is eligible pursuant to the Trust
         Indenture Act to act as such and has a combined capital and surplus of
         at least $50,000,000, and shall be a corporation meeting the
         requirements of Section 310(a) of the Trust Indenture Act. If such
         corporation publishes reports of condition at least annually, pursuant
         to law or to the requirements of the supervising or examining
         authority, then, for the purposes of this Section 4.1 and to the extent
         permitted by the Trust Indenture Act, the combined capital and surplus
         of such corporation shall be deemed to be its combined capital and
         surplus as set forth in its most recent report of condition so
         published.

         (b) If at any time the Guarantee Trustee shall cease to be eligible to
so act under Section 4.1(a), the Guarantee Trustee shall immediately resign in
the manner and with the effect set out in Section 4.2(c).

         (c) If the Guarantee Trustee has or shall acquire any "conflicting
interest" within the meaning of Section 310(b) of the Trust Indenture Act, the
Guarantee Trustee and Guarantor shall in all respects comply with the provisions
of Section 310(b) of the Trust Indenture Act.

         SECTION 4.2. Appointment, Removal and Resignation of the Guarantee
Trustee.

         (a) Subject to Section 4.2(b), the Guarantee Trustee may be appointed
or removed without cause at any time by the Guarantor.

         (b) The Guarantee Trustee shall not be removed until a Successor
Guarantee Trustee has been appointed and has accepted such appointment by
written instrument executed by such Successor Guarantee Trustee and delivered to
the Guarantor.

         (c) The Guarantee Trustee appointed hereunder shall hold office until a
Successor Guarantee Trustee shall have been appointed or until its removal or
resignation. The Guarantee Trustee may resign from office (without need for
prior or subsequent accounting) by an instrument in writing executed by the
Guarantee Trustee and delivered to the Guarantor, which resignation shall not
take effect until a Successor Guarantee Trustee has been appointed and has
accepted such appointment by instrument in writing executed by such Successor
Guarantee Trustee and delivered to the Guarantor and the resigning Guarantee
Trustee.

         (d) If no Successor Guarantee Trustee shall have been appointed and
accepted appointment as provided in this Section 4.2 within 60 days after
delivery to the Guarantor of an instrument of resignation, the resigning
Guarantee Trustee may petition, at the expense of the Guarantor, any court of
competent jurisdiction for appointment of a Successor Guarantee Trustee. Such
court may thereupon, after prescribing such notice, if any, as it may deem
proper, appoint a Successor Guarantee Trustee.




                                       12
<PAGE>   17



                                    ARTICLE V

                                    GUARANTEE

         SECTION 5.1. Guarantee.

         The Guarantor irrevocably and unconditionally agrees to pay in full to
the Holders the Guarantee Payments (without duplication of amounts theretofore
paid by or on behalf of the Issuer Trust), as and when due, regardless of any
defense, right of set-off or counterclaim which the Issuer Trust may have or
assert. The Guarantor's obligation to make a Guarantee Payment may be satisfied
by direct payment of the required amounts by the Guarantor to the Holders or by
causing the Issuer Trust to pay such amounts to the Holders.

         SECTION 5.2. Waiver of Notice and Demand.

         The Guarantor hereby waives notice of acceptance of the Guarantee
Agreement and of any liability to which it applies or may apply, presentment,
demand for payment, any right to require a proceeding first against the
Guarantee Trustee, Issuer Trust or any other Person before proceeding against
the Guarantor, protest, notice of nonpayment, notice of dishonor, notice of
redemption and all other notices and demands.

         SECTION 5.3. Obligations Not Affected.

         The obligations, covenants, agreements and duties of the Guarantor
under this Guarantee Agreement shall in no way be affected or impaired by reason
of the happening from time to time of any of the following:

                  (a) the release or waiver, by operation of law or otherwise,
         of the performance or observance by the Issuer Trust of any express or
         implied agreement, covenant, term or condition relating to the Capital
         Securities to be performed or observed by the Issuer Trust;

                  (b) the extension of time for the payment by the Issuer Trust
         of all or any portion of the Distributions (other than an extension of
         time for payment of Distributions that results from the extension of
         any interest payment period on the Junior Subordinated Debentures as
         provided in the Indenture), Redemption Price, Liquidation Distribution
         or any other sums payable under the terms of the Capital Securities or
         the extension of time for the performance of any other obligation
         under, arising out of, or in connection with, the Capital Securities;

                  (c) any failure, omission, delay or lack of diligence on the
         part of the Holders to enforce, assert or exercise any right,
         privilege, power or remedy conferred on the Holders 




                                       13
<PAGE>   18




         pursuant to the terms of the Capital Securities, or any action on the 
         part of the Issuer Trust granting indulgence or extension of any kind;

                  (d) the voluntary or involuntary liquidation, dissolution,
         sale of any collateral, receivership, insolvency, bankruptcy,
         assignment for the benefit of creditors, reorganization, arrangement,
         composition or readjustment of debt of, or other similar proceedings
         affecting, the Issuer Trust or any of the assets of the Issuer Trust;

                  (e) any invalidity of, or defect or deficiency in, the Capital
         Securities;

                  (f) the settlement or compromise of any obligation guaranteed
         hereby or hereby incurred; or

                  (g) any other circumstance whatsoever that might otherwise
         constitute a legal or equitable discharge or defense of a guarantor, it
         being the intent of this Section 5.3 that the obligations of the
         Guarantor hereunder shall be absolute and unconditional under any and
         all circumstances.

There shall be no obligation of the Holders to give notice to, or obtain the
consent of, the Guarantor with respect to the happening of any of the foregoing.

         SECTION 5.4. Rights of Holders.

         The Guarantor expressly acknowledges that: (i) this Guarantee Agreement
will be deposited with the Guarantee Trustee to be held for the benefit of the
Holders; (ii) the Guarantee Trustee has the right to enforce this Guarantee
Agreement on behalf of the Holders; (iii) the Holders of a Majority in
Liquidation Amount of the Capital Securities have the right to direct the time,
method and place of conducting any proceeding for any remedy available to the
Guarantee Trustee in respect of this Guarantee Agreement or exercising any trust
or power conferred upon the Guarantee Trustee under this Guarantee Agreement;
and (iv) any Holder may institute a legal proceeding directly against the
Guarantor to enforce its rights under this Guarantee Agreement, without first
instituting a legal proceeding against the Guarantee Trustee, the Issuer Trust
or any other Person.

         SECTION 5.5. Guarantee of Payment.

         This Guarantee Agreement creates a guarantee of payment and not of
collection. This Guarantee Agreement will not be discharged except by payment of
the Guarantee Payments in full (without duplication of amounts theretofore paid
by the Issuer Trust) or upon distribution of Junior Subordinated Debentures to
Holders as provided in the Trust Agreement.



                                       14
<PAGE>   19



         SECTION 5.6. Subrogation.

         The Guarantor shall be subrogated to all (if any) rights of the Holders
against the Issuer Trust in respect of any amounts paid to the Holders by the
Guarantor under this Guarantee Agreement and shall have the right to waive
payment by the Issuer Trust pursuant to Section 5.1; provided, however, that the
Guarantor shall not (except to the extent required by mandatory provisions of
law) be entitled to enforce or exercise any rights which it may acquire by way
of subrogation or any indemnity, reimbursement or other agreement, in all cases
as a result of payment under this Guarantee Agreement, if, at the time of any
such payment, any amounts are due and unpaid under this Guarantee Agreement. If
any amount shall be paid to the Guarantor in violation of the preceding
sentence, the Guarantor agrees to hold such amount in trust for the Holders and
to pay over such amount to the Holders.

         SECTION 5.7. Independent Obligations.

         The Guarantor acknowledges that its obligations hereunder are
independent of the obligations of the Issuer Trust with respect to the Capital
Securities and that the Guarantor shall be liable as principal and as debtor
hereunder to make Guarantee Payments pursuant to the terms of this Guarantee
Agreement notwithstanding the occurrence of any event referred to in subsections
(a) through (g), inclusive, of Section 5.3 hereof.


                                   ARTICLE VI

                           COVENANTS AND SUBORDINATION

         SECTION 6.1. Subordination.

         The obligations of the Guarantor under this Guarantee Agreement will
constitute unsecured obligations of the Guarantor and will rank subordinate and
junior in right of payment to all Senior Indebtedness of the Guarantor in the
same manner as the Junior Subordinated Debentures. The obligations of the
Guarantor under this Guarantee Agreement do not constitute Senior Indebtedness,
Senior Debt or Senior Subordinated Debt.

         SECTION 6.2. Pari Passu Guarantees.

         The obligations of the Guarantor under this Guarantee Agreement shall
rank pari passu with the obligations of the Guarantor under any similar
guarantee agreements issued by the Guarantor on behalf of the holders of
preferred or capital securities issued by any KeyCorp Trust (as defined in the
Indenture).



                                       15
<PAGE>   20




                                   ARTICLE VII

                                   TERMINATION

         SECTION 7.1. Termination.

         This Guarantee Agreement shall terminate and be of no further force and
effect upon (i) full payment of the Redemption Price of all Capital Securities,
(ii) the distribution of Junior Subordinated Debentures to the Holders in
exchange for all of the Capital Securities or (iii) full payment of the amounts
payable in accordance with the Trust Agreement upon liquidation of the Issuer
Trust. Notwithstanding the foregoing, this Guarantee Agreement will continue to
be effective or will be reinstated, as the case may be, if at any time any
Holder must restore payment of any sums paid with respect to Capital Securities
or this Guarantee Agreement.


                                  ARTICLE VIII

                                  MISCELLANEOUS

         SECTION 8.1. Successors and Assigns.

         All guarantees and agreements contained in this Guarantee Agreement
shall bind the successors, assigns, receivers, trustees and representatives of
the Guarantor and shall inure to the benefit of the Holders of the Capital
Securities then outstanding. Except in connection with a consolidation, merger
or sale involving the Guarantor that is permitted under Article VIII of the
Indenture and pursuant to which the successor or assignee agrees in writing to
perform the Guarantor's obligations hereunder, the Guarantor shall not assign
its obligations hereunder.

         SECTION 8.2. Amendments.

         Except with respect to any changes which do not adversely affect the
rights of the Holders in any material respect (in which case no consent of the
Holders will be required), this Guarantee Agreement may only be amended with the
prior approval of the Holders of not less than a Majority in Liquidation Amount
of the Capital Securities. The provisions of Article VI of the Trust Agreement
concerning meetings of the Holders shall apply to the giving of such approval.

         SECTION 8.3. Notices.

         Any notice, request or other communication required or permitted to be
given hereunder shall be in writing, duly signed by the party giving such
notice, and delivered, telecopied or mailed by first class mail as follows:






                                       16
<PAGE>   21



                  (a) if given to the Guarantor, to the address set forth below
         or such other address, facsimile number or to the attention of such
         other Person as the Guarantor may give notice to the Holders:

                           KeyCorp
                           127 Public Square
                           Cleveland, Ohio 44114-1306

                           Facsimile No.: (216) 689-4121
                           Attention: General Counsel

                  (b) if given to the Issuer Trust, in care of the Guarantee
         Trustee, at the Issuer Trust's (and the Guarantee Trustee's) address
         set forth below or such other address as the Guarantee Trustee on
         behalf of the Issuer Trust may give notice to the Holders:

                           KeyCorp Institutional Capital B
                           c/o KeyCorp
                           127 Public Square
                           Cleveland, Ohio 44114-1306

                           Facsimile No.: (216) 689-4121
                           Attention: General Counsel

                  with a copy to:

                           Bankers Trust Company
                           Four Albany Street
                           Mail Stop 5041
                           New York, New York  10006

                           Facsimile No.: (212) 250-6395
                           Attention: Kevin Weeks

                  (c) if given to any Holder, at the address set forth on the
         books and records of the Issuer Trust.

         All notices hereunder shall be deemed to have been given when received
in person, telecopied with receipt confirmed, or mailed by first class mail,
postage prepaid, except that if a notice or other document is refused delivery
or cannot be delivered because of a changed address of which no notice was
given, such notice or other document shall be deemed to have been delivered on
the date of such refusal or inability to deliver.




                                       17
<PAGE>   22





         SECTION 8.4. Benefit.

         This Guarantee Agreement is solely for the benefit of the Holders and
is not separately transferable from the Capital Securities.

         SECTION 8.5. Governing Law.

         THIS GUARANTEE AGREEMENT SHALL BE GOVERNED BY AND CONSTRUED AND
INTERPRETED IN ACCORDANCE WITH THE LAWS OF THE STATE OF NEW YORK.

         SECTION 8.6. Counterparts.

         This instrument may be executed in any number of counterparts, each of
which so executed shall be deemed to be an original, but all such counterparts
shall together constitute but one and the same instrument.


                                       18

<PAGE>   23


         IN WITNESS WHEREOF, the undersigned have executed this Guarantee
Agreement as of the date first above written.




                                             KEYCORP                        
                                                                            
                                                                            
                                             By:                            
                                                ----------------------------
                                                  Name: 
                                                  Title:  
                                                                            
                                                                            
                                             BANKERS TRUST COMPANY          
                                                      as Guarantee Trustee  
                                                                            
                                                                            
                                             By:                            
                                                 ---------------------------
                                                  Name: 
                                                  Title: 


                                       19




