<SEC-DOCUMENT>0001321732-16-000010.txt : 20160523
<SEC-HEADER>0001321732-16-000010.hdr.sgml : 20160523
<ACCEPTANCE-DATETIME>20160523190601
ACCESSION NUMBER:		0001321732-16-000010
CONFORMED SUBMISSION TYPE:	4
PUBLIC DOCUMENT COUNT:		1
CONFORMED PERIOD OF REPORT:	20160519
FILED AS OF DATE:		20160523
DATE AS OF CHANGE:		20160523

ISSUER:		

	COMPANY DATA:	
		COMPANY CONFORMED NAME:			Penumbra Inc
		CENTRAL INDEX KEY:			0001321732
		STANDARD INDUSTRIAL CLASSIFICATION:	SURGICAL & MEDICAL INSTRUMENTS & APPARATUS [3841]
		IRS NUMBER:				000000000
		STATE OF INCORPORATION:			DE
		FISCAL YEAR END:			1231

	BUSINESS ADDRESS:	
		STREET 1:		1351 HARBOR BAY PARKWAY
		CITY:			ALAMEDA
		STATE:			CA
		ZIP:			94502
		BUSINESS PHONE:		(510) 995-2486

	MAIL ADDRESS:	
		STREET 1:		1351 HARBOR BAY PARKWAY
		CITY:			ALAMEDA
		STATE:			CA
		ZIP:			94502

REPORTING-OWNER:	

	OWNER DATA:	
		COMPANY CONFORMED NAME:			Kassing Don W.
		CENTRAL INDEX KEY:			0001651324

	FILING VALUES:
		FORM TYPE:		4
		SEC ACT:		1934 Act
		SEC FILE NUMBER:	001-37557
		FILM NUMBER:		161670478

	MAIL ADDRESS:	
		STREET 1:		1351 HARBOR BAY PARKWAY
		CITY:			ALAMEDA
		STATE:			CA
		ZIP:			94502
</SEC-HEADER>
<DOCUMENT>
<TYPE>4
<SEQUENCE>1
<FILENAME>wf-form4_146404474794397.xml
<DESCRIPTION>FORM 4
<TEXT>
<XML>
<?xml version="1.0"?>
<ownershipDocument>

    <schemaVersion>X0306</schemaVersion>

    <documentType>4</documentType>

    <periodOfReport>2016-05-19</periodOfReport>

    <notSubjectToSection16>0</notSubjectToSection16>

    <issuer>
        <issuerCik>0001321732</issuerCik>
        <issuerName>Penumbra Inc</issuerName>
        <issuerTradingSymbol>PEN</issuerTradingSymbol>
    </issuer>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001651324</rptOwnerCik>
            <rptOwnerName>Kassing Don W.</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>ONE PENUMBRA PLACE</rptOwnerStreet1>
            <rptOwnerStreet2>1351 HARBOR BAY PARKWAY</rptOwnerStreet2>
            <rptOwnerCity>ALAMEDA</rptOwnerCity>
            <rptOwnerState>CA</rptOwnerState>
            <rptOwnerZipCode>94502</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>1</isDirector>
            <isOfficer>0</isOfficer>
            <isTenPercentOwner>0</isTenPercentOwner>
            <isOther>0</isOther>
            <officerTitle></officerTitle>
            <otherText></otherText>
        </reportingOwnerRelationship>
    </reportingOwner>

    <nonDerivativeTable>
        <nonDerivativeTransaction>
            <securityTitle>
                <value>Common Stock</value>
            </securityTitle>
            <transactionDate>
                <value>2016-05-19</value>
            </transactionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>S</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
                <footnoteId id="F1"/>
            </transactionCoding>
            <transactionAmounts>
                <transactionShares>
                    <value>3000</value>
                </transactionShares>
                <transactionPricePerShare>
                    <value>48.6301</value>
                    <footnoteId id="F2"/>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>D</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>13000</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>I</value>
                </directOrIndirectOwnership>
                <natureOfOwnership>
                    <value>By Trust</value>
                    <footnoteId id="F3"/>
                </natureOfOwnership>
            </ownershipNature>
        </nonDerivativeTransaction>
        <nonDerivativeHolding>
            <securityTitle>
                <value>Common Stock</value>
                <footnoteId id="F4"/>
            </securityTitle>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>4000</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </nonDerivativeHolding>
    </nonDerivativeTable>

    <derivativeTable></derivativeTable>

    <footnotes>
        <footnote id="F1">Sale primarily to cover existing and arising tax liabilities</footnote>
        <footnote id="F2">This transaction was executed in multiple trades at prices ranging from $48.44 to $48.67.  The price reported above reflects the weighted average sale price. The reporting person hereby undertakes to provide upon request to the SEC staff, the issuer or security holder of the issuer full information regarding the number of shares and prices at which the transaction was effected.</footnote>
        <footnote id="F3">Shares are held by The Kassing Family Trust.</footnote>
        <footnote id="F4">Includes restricted stock units vested/vesting as to 1/4 on each of March 31, 2016, June 30, 2016, September 30, 2016 and December 31, 2016.</footnote>
    </footnotes>

    <remarks></remarks>

    <ownerSignature>
        <signatureName>/s/ Sukhindra Mata, as attorney-in-fact for Don W. Kassing</signatureName>
        <signatureDate>2016-05-23</signatureDate>
    </ownerSignature>
</ownershipDocument>
</XML>
</TEXT>
</DOCUMENT>
</SEC-DOCUMENT>
