<SEC-DOCUMENT>0001595974-16-000040.txt : 20160802
<SEC-HEADER>0001595974-16-000040.hdr.sgml : 20160802
<ACCEPTANCE-DATETIME>20160802213914
ACCESSION NUMBER:		0001595974-16-000040
CONFORMED SUBMISSION TYPE:	3
PUBLIC DOCUMENT COUNT:		2
CONFORMED PERIOD OF REPORT:	20160802
FILED AS OF DATE:		20160802
DATE AS OF CHANGE:		20160802

ISSUER:		

	COMPANY DATA:	
		COMPANY CONFORMED NAME:			RUBICON PROJECT, INC.
		CENTRAL INDEX KEY:			0001595974
		STANDARD INDUSTRIAL CLASSIFICATION:	SERVICES-COMPUTER PROGRAMMING, DATA PROCESSING, ETC. [7370]
		IRS NUMBER:				208881738
		STATE OF INCORPORATION:			DE
		FISCAL YEAR END:			1231

	BUSINESS ADDRESS:	
		STREET 1:		12181 BLUFF CREEK DRIVE, 4TH FLOOR
		CITY:			LOS ANGELES
		STATE:			CA
		ZIP:			90094
		BUSINESS PHONE:		310-207-0272

	MAIL ADDRESS:	
		STREET 1:		12181 BLUFF CREEK DRIVE, 4TH FLOOR
		CITY:			LOS ANGELES
		STATE:			CA
		ZIP:			90094

REPORTING-OWNER:	

	OWNER DATA:	
		COMPANY CONFORMED NAME:			Richter James Neal
		CENTRAL INDEX KEY:			0001680756

	FILING VALUES:
		FORM TYPE:		3
		SEC ACT:		1934 Act
		SEC FILE NUMBER:	001-36384
		FILM NUMBER:		161802090

	MAIL ADDRESS:	
		STREET 1:		C/O THE RUBICON PROJECT, INC.
		STREET 2:		12181 BLUFF CREEK DRIVE, 4TH FL
		CITY:			LOS ANGELES
		STATE:			CA
		ZIP:			90094
</SEC-HEADER>
<DOCUMENT>
<TYPE>3
<SEQUENCE>1
<FILENAME>wf-form3_147018834150666.xml
<DESCRIPTION>FORM 3
<TEXT>
<XML>
<?xml version="1.0"?>
<ownershipDocument>

    <schemaVersion>X0206</schemaVersion>

    <documentType>3</documentType>

    <periodOfReport>2016-08-02</periodOfReport>

    <noSecuritiesOwned>0</noSecuritiesOwned>

    <issuer>
        <issuerCik>0001595974</issuerCik>
        <issuerName>RUBICON PROJECT, INC.</issuerName>
        <issuerTradingSymbol>RUBI</issuerTradingSymbol>
    </issuer>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001680756</rptOwnerCik>
            <rptOwnerName>Richter James Neal</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>C/O THE RUBICON PROJECT, INC.</rptOwnerStreet1>
            <rptOwnerStreet2>12181 BLUFF CREEK DRIVE, 4TH FL</rptOwnerStreet2>
            <rptOwnerCity>LOS ANGELES</rptOwnerCity>
            <rptOwnerState>CA</rptOwnerState>
            <rptOwnerZipCode>90094</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>0</isDirector>
            <isOfficer>1</isOfficer>
            <isTenPercentOwner>0</isTenPercentOwner>
            <isOther>0</isOther>
            <officerTitle>Chief Technology Officer</officerTitle>
            <otherText></otherText>
        </reportingOwnerRelationship>
    </reportingOwner>

    <nonDerivativeTable>
        <nonDerivativeHolding>
            <securityTitle>
                <value>Common Stock</value>
            </securityTitle>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>117316</value>
                    <footnoteId id="F1"/>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </nonDerivativeHolding>
    </nonDerivativeTable>

    <derivativeTable>
        <derivativeHolding>
            <securityTitle>
                <value>Stock Option (right to buy)</value>
            </securityTitle>
            <conversionOrExercisePrice>
                <value>4.7</value>
            </conversionOrExercisePrice>
            <exerciseDate>
                <footnoteId id="F2"/>
            </exerciseDate>
            <expirationDate>
                <value>2021-12-07</value>
            </expirationDate>
            <underlyingSecurity>
                <underlyingSecurityTitle>
                    <value>Common Stock</value>
                </underlyingSecurityTitle>
                <underlyingSecurityShares>
                    <value>14500.0</value>
                </underlyingSecurityShares>
            </underlyingSecurity>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </derivativeHolding>
        <derivativeHolding>
            <securityTitle>
                <value>Stock Option (right to buy)</value>
            </securityTitle>
            <conversionOrExercisePrice>
                <value>4.7</value>
            </conversionOrExercisePrice>
            <exerciseDate>
                <footnoteId id="F3"/>
            </exerciseDate>
            <expirationDate>
                <value>2022-05-22</value>
            </expirationDate>
            <underlyingSecurity>
                <underlyingSecurityTitle>
                    <value>Common Stock</value>
                </underlyingSecurityTitle>
                <underlyingSecurityShares>
                    <value>35499.0</value>
                </underlyingSecurityShares>
            </underlyingSecurity>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </derivativeHolding>
        <derivativeHolding>
            <securityTitle>
                <value>Stock Option (right to buy)</value>
            </securityTitle>
            <conversionOrExercisePrice>
                <value>16.75</value>
            </conversionOrExercisePrice>
            <exerciseDate>
                <footnoteId id="F4"/>
            </exerciseDate>
            <expirationDate>
                <value>2025-05-19</value>
            </expirationDate>
            <underlyingSecurity>
                <underlyingSecurityTitle>
                    <value>Common Stock</value>
                </underlyingSecurityTitle>
                <underlyingSecurityShares>
                    <value>15800.0</value>
                </underlyingSecurityShares>
            </underlyingSecurity>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </derivativeHolding>
    </derivativeTable>

    <footnotes>
        <footnote id="F1">Represents: (i) 29,948 shares of restricted stock that vest as follows: 7,812 on November 15, 2016, 7,813 on May 15, 2017, 7,812 on November 15, 2017, and 6,511 on May 15, 2018; (ii) 29,357 restricted stock units that vest as follows: 5,338 on November 15, 2016, 5,337 on May 15, 2017, 5,338 on November 15, 2017, 5,337 on May 15, 2018, 5,338 on November 15, 2018, and 2,669 on May 15, 2019; (iii) 50,000 RSUs that vest as follows: 15,625 on May 15, 2017, 6,250 on each November 15 and May 15 thereafter until November 15, 2019, and 3,125 on May 15, 2020; and (iv) 8,011 shares of common stock.</footnote>
        <footnote id="F2">The option, originally representing a right to purchase a total of 20,000 shares, became exercisable with respect to 25% of the grant on October 27, 2012 and became exercisable with respect to the remainder in 36 equal installments each calendar month thereafter and is now fully vested.</footnote>
        <footnote id="F3">The option, originally representing a right to purchase a total of 79,999 shares, became exercisable with respect to 25% of the grant on April 1, 2013 and became exercisable with respect to the remainder in 36 equal installments each calendar month thereafter and is now fully vested.</footnote>
        <footnote id="F4">The option, representing a right to purchase a total of 15,800 shares, became exercisable with respect to 25% of the grant on February 1, 2016 and becomes exercisable with respect to the remainder in 36 equal installments each calendar month thereafter.</footnote>
    </footnotes>

    <remarks></remarks>

    <ownerSignature>
        <signatureName>Jonathan Feldman, attorney-in-fact</signatureName>
        <signatureDate>2016-08-02</signatureDate>
    </ownerSignature>
</ownershipDocument>
</XML>
</TEXT>
</DOCUMENT>
<DOCUMENT>
<TYPE>EX-24
<SEQUENCE>2
<FILENAME>powerofattorney.htm
<DESCRIPTION>POWER OF ATTORNEY
<TEXT>
<!-- Document created using Workiva -->
<html>
<body>
<pre>
EXHIBIT 24

                POWER OF ATTORNEY

        FOR SEC FILINGS ON FORMS ID, 3, 4, 5 AND 144
              IN RESPECT OF SECURITIES OF
                   THE RUBICON PROJECT, INC.

             The undersigned hereby constitutes and appoints Brian Copple, David Day and Jonathan Feldman, and each of them, as his true and lawful attorney-in-fact and agent, with full power of substitution and resubstitution for him in his name and stead in any and all capacities, to sign and file for and on his behalf, in respect of any acquisition, disposition or other change in ownership of any Common Stock of The Rubicon Project, Inc. (the Company), the following:

    (i)     any Form ID to be filed with the Securities and Exchange Commission (the SEC);
    (ii)    any Initial Statement of Beneficial Ownership of Securities on Form 3 to be filed with the SEC;
    (iii)    any Statement of Changes of Beneficial Ownership of Securities on Form 4 to be filed with the SEC;
    (iv)    any Annual Statement of Beneficial Ownership of Securities on Form 5 to be filed with the SEC;
    (v)    any Notice of Proposed Sale of Securities on Form 144 to be filed with the SEC; and
    (vi)    any and all agreements, certificates, receipts, or other documents in connection therewith.

    The undersigned hereby gives full power and authority to the attorney-in-fact to seek and obtain as the undersignedTMs representative and on the undersignedTMs behalf, information on transactions in the CompanyTMs securities from any third party, including brokers, employee benefit plan administrators and trustees, and the undersigned hereby authorizes any such person to release such information to the undersigned and approves and ratifies any such release of information.

    The undersigned hereby grants unto such attorney-in-fact and agent full power and authority to do and perform each and every act and thing requisite and necessary in connection with such matters and hereby ratifies and confirms all that any such attorney-in-fact and agent or substitute may do or cause to be done by virtue hereof.

    The undersigned acknowledges that:

    (i)    neither the Company nor such attorney-in-fact assumes (i) any liability for the undersignedTMs responsibility to comply with the requirement of the Securities Exchange Act of 1934, as amended (the Exchange Act), (ii) any liability of the undersigned for any failure to comply with such requirements or (iii) any obligation or liability of the undersigned for profit disgorgement under Section 16(b) of the Exchange Act; and

    (ii)    this Power of Attorney does not relieve the undersigned from responsibility for compliance with the undersignedTMs obligations under the Exchange Act, including without limitation the reporting requirements under Section 16 of the Exchange Act.

             This Power of Attorney shall remain in full force and effect until revoked by the undersigned in a signed writing delivered to such attorney-in-fact.

             IN WITNESS WHEREOF, the undersigned has executed this Power of Attorney.

Date:  July 25, 2016                /s/ James Neal Richter
                        _________________________
                        James Neal Richter




</pre>
</body>
</html>
</TEXT>
</DOCUMENT>
</SEC-DOCUMENT>
