<SEC-DOCUMENT>0001209191-21-055581.txt : 20210910
<SEC-HEADER>0001209191-21-055581.hdr.sgml : 20210910
<ACCEPTANCE-DATETIME>20210910201154
ACCESSION NUMBER:		0001209191-21-055581
CONFORMED SUBMISSION TYPE:	4
PUBLIC DOCUMENT COUNT:		1
CONFORMED PERIOD OF REPORT:	20210908
FILED AS OF DATE:		20210910
DATE AS OF CHANGE:		20210910

REPORTING-OWNER:	

	OWNER DATA:	
		COMPANY CONFORMED NAME:			Saltz Aaron
		CENTRAL INDEX KEY:			0001807986

	FILING VALUES:
		FORM TYPE:		4
		SEC ACT:		1934 Act
		SEC FILE NUMBER:	001-36384
		FILM NUMBER:		211248301

	MAIL ADDRESS:	
		STREET 1:		C/O TELARIA INC.
		STREET 2:		222 BROADWAY, 16TH FLOOR
		CITY:			NEW YORK
		STATE:			NY
		ZIP:			10038

ISSUER:		

	COMPANY DATA:	
		COMPANY CONFORMED NAME:			MAGNITE, 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

	FORMER COMPANY:	
		FORMER CONFORMED NAME:	RUBICON PROJECT, INC.
		DATE OF NAME CHANGE:	20140106
</SEC-HEADER>
<DOCUMENT>
<TYPE>4
<SEQUENCE>1
<FILENAME>doc4.xml
<DESCRIPTION>FORM 4 SUBMISSION
<TEXT>
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        <issuerCik>0001595974</issuerCik>
        <issuerName>MAGNITE, INC.</issuerName>
        <issuerTradingSymbol>MGNI</issuerTradingSymbol>
    </issuer>

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            <rptOwnerName>Saltz Aaron</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>C/O MAGNITE, INC.</rptOwnerStreet1>
            <rptOwnerStreet2>6080 CENTER DRIVE, 4TH FLOOR</rptOwnerStreet2>
            <rptOwnerCity>LOS ANGELES</rptOwnerCity>
            <rptOwnerState>CA</rptOwnerState>
            <rptOwnerZipCode>90045</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>0</isDirector>
            <isOfficer>1</isOfficer>
            <isTenPercentOwner>0</isTenPercentOwner>
            <isOther>0</isOther>
            <officerTitle>General Counsel</officerTitle>
        </reportingOwnerRelationship>
    </reportingOwner>

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                <sharesOwnedFollowingTransaction>
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            <transactionTimeliness>
                <value></value>
            </transactionTimeliness>
            <transactionAmounts>
                <transactionShares>
                    <value>4575</value>
                </transactionShares>
                <transactionPricePerShare>
                    <value>5.16</value>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>A</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>306482</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
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                    <value>D</value>
                </directOrIndirectOwnership>
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        </nonDerivativeTransaction>
        <nonDerivativeTransaction>
            <securityTitle>
                <value>Common Stock</value>
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            <transactionDate>
                <value>2021-09-10</value>
            </transactionDate>
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            <transactionTimeliness>
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            </transactionTimeliness>
            <transactionAmounts>
                <transactionShares>
                    <value>40004</value>
                </transactionShares>
                <transactionPricePerShare>
                    <value>30.21</value>
                    <footnoteId id="F1"/>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>D</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
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                <sharesOwnedFollowingTransaction>
                    <value>266478</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
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                    <value>D</value>
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        </nonDerivativeTransaction>
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    <derivativeTable>
        <derivativeTransaction>
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            </securityTitle>
            <conversionOrExercisePrice>
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            </conversionOrExercisePrice>
            <transactionDate>
                <value>2021-09-08</value>
            </transactionDate>
            <deemedExecutionDate></deemedExecutionDate>
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                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionTimeliness>
                <value></value>
            </transactionTimeliness>
            <transactionAmounts>
                <transactionShares>
                    <value>5410</value>
                </transactionShares>
                <transactionPricePerShare>
                    <value>0.00</value>
                    <footnoteId id="F3"/>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>D</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <exerciseDate>
                <footnoteId id="F2"/>
            </exerciseDate>
            <expirationDate>
                <value>2023-07-31</value>
            </expirationDate>
            <underlyingSecurity>
                <underlyingSecurityTitle>
                    <value>Common Stock</value>
                </underlyingSecurityTitle>
                <underlyingSecurityShares>
                    <value>5410</value>
                </underlyingSecurityShares>
            </underlyingSecurity>
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            </securityTitle>
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            </conversionOrExercisePrice>
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                <value>2021-09-08</value>
            </transactionDate>
            <deemedExecutionDate></deemedExecutionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>M</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
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            <transactionTimeliness>
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                </transactionShares>
                <transactionPricePerShare>
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                <transactionAcquiredDisposedCode>
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            <expirationDate>
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            </expirationDate>
            <underlyingSecurity>
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                <underlyingSecurityShares>
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                <transactionShares>
                    <value>8264</value>
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                <transactionPricePerShare>
                    <value>0.00</value>
                    <footnoteId id="F3"/>
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                <transactionAcquiredDisposedCode>
                    <value>D</value>
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            </transactionAmounts>
            <exerciseDate>
                <footnoteId id="F5"/>
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            <expirationDate>
                <value>2028-02-27</value>
            </expirationDate>
            <underlyingSecurity>
                <underlyingSecurityTitle>
                    <value>Common Stock</value>
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                <underlyingSecurityShares>
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                </underlyingSecurityShares>
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                <sharesOwnedFollowingTransaction>
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                </sharesOwnedFollowingTransaction>
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                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
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        </derivativeTransaction>
        <derivativeTransaction>
            <securityTitle>
                <value>Stock Option (Right to Buy)</value>
            </securityTitle>
            <conversionOrExercisePrice>
                <value>5.16</value>
            </conversionOrExercisePrice>
            <transactionDate>
                <value>2021-09-10</value>
            </transactionDate>
            <deemedExecutionDate></deemedExecutionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>M</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
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            <transactionTimeliness>
                <value></value>
            </transactionTimeliness>
            <transactionAmounts>
                <transactionShares>
                    <value>4575</value>
                </transactionShares>
                <transactionPricePerShare>
                    <value>0.00</value>
                    <footnoteId id="F3"/>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>D</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <exerciseDate>
                <footnoteId id="F6"/>
            </exerciseDate>
            <expirationDate>
                <value>2029-02-28</value>
            </expirationDate>
            <underlyingSecurity>
                <underlyingSecurityTitle>
                    <value>Common Stock</value>
                </underlyingSecurityTitle>
                <underlyingSecurityShares>
                    <value>4575</value>
                </underlyingSecurityShares>
            </underlyingSecurity>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>22872</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </derivativeTransaction>
    </derivativeTable>

    <footnotes>
        <footnote id="F1">The price reported in Column 4 is a weighted average price. These shares were sold in multiple transactions at prices ranging from $30.15 to $30.33, inclusive. The Reporting Person undertakes to provide to the Issuer, any security holder of the Issuer, or the staff of the Securities and Exchange Commission, upon request, full information regarding the number of shares sold at each separate price within the range set forth in this footnote.</footnote>
        <footnote id="F2">This option is fully vested and immediately exercisable.</footnote>
        <footnote id="F3">Equity grant under the Company's 2014 Equity Incentive Plan.</footnote>
        <footnote id="F4">25% of the total number of shares underlying this option vested on April 1, 2021 and the remaining shares vest 1/36 per month over the next 36 months thereafter, subject to continued service to the Issuer through each vesting date. This equity grant may be subject to accelerated vesting in the event the Reporting Person's employment is terminated under certain circumstances.</footnote>
        <footnote id="F5">25% of the total number of shares underlying this option vested on February 14, 2019 and the remaining shares vest 1/36 per month over the next 36 months thereafter, subject to continued service to the Issuer through each vesting date. This equity grant may be subject to accelerated vesting in the event the Reporting Person's employment is terminated under certain circumstances.</footnote>
        <footnote id="F6">25% of the total number of shares underlying this option vested on February 14, 2020 and the remaining shares vest 1/36 per month over the next 36 months thereafter, subject to continued service to the Issuer through each vesting date. This equity grant may be subject to accelerated vesting in the event the Reporting Person's employment is terminated under certain circumstances.</footnote>
    </footnotes>

    <remarks></remarks>

    <ownerSignature>
        <signatureName>/s/ Aaron Saltz</signatureName>
        <signatureDate>2021-09-10</signatureDate>
    </ownerSignature>
</ownershipDocument>
</XML>
</TEXT>
</DOCUMENT>
</SEC-DOCUMENT>
