<SEC-DOCUMENT>0001140361-26-008322.txt : 20260309
<SEC-HEADER>0001140361-26-008322.hdr.sgml : 20260309
<ACCEPTANCE-DATETIME>20260309060159
ACCESSION NUMBER:		0001140361-26-008322
CONFORMED SUBMISSION TYPE:	4
PUBLIC DOCUMENT COUNT:		1
CONFORMED PERIOD OF REPORT:	20260305
FILED AS OF DATE:		20260309
DATE AS OF CHANGE:		20260309

REPORTING-OWNER:	

	OWNER DATA:	
		COMPANY CONFORMED NAME:			Kummeth Charles R.
		CENTRAL INDEX KEY:			0001534980
		ORGANIZATION NAME:           	

	FILING VALUES:
		FORM TYPE:		4
		SEC ACT:		1934 Act
		SEC FILE NUMBER:	001-39486
		FILM NUMBER:		26733088

	MAIL ADDRESS:	
		STREET 1:		425 MARTINGALE ROAD
		STREET 2:		SUITE 1000
		CITY:			SCHAUMBURG
		STATE:			IL
		ZIP:			60173-2213

ISSUER:		

	COMPANY DATA:	
		COMPANY CONFORMED NAME:			Quantum-Si Inc
		CENTRAL INDEX KEY:			0001816431
		STANDARD INDUSTRIAL CLASSIFICATION:	MEASURING & CONTROLLING DEVICES, NEC [3829]
		ORGANIZATION NAME:           	08 Industrial Applications and Services
		EIN:				851388175
		STATE OF INCORPORATION:			DE
		FISCAL YEAR END:			1231

	BUSINESS ADDRESS:	
		STREET 1:		29 BUSINESS PARK DRIVE
		CITY:			BRANFORD
		STATE:			CT
		ZIP:			06405
		BUSINESS PHONE:		(203) 458-7100

	MAIL ADDRESS:	
		STREET 1:		29 BUSINESS PARK DRIVE
		CITY:			BRANFORD
		STATE:			CT
		ZIP:			06405

	FORMER COMPANY:	
		FORMER CONFORMED NAME:	HighCape Capital Acquisition Corp.
		DATE OF NAME CHANGE:	20200629
</SEC-HEADER>
<DOCUMENT>
<TYPE>4
<SEQUENCE>1
<FILENAME>form4.xml
<DESCRIPTION>FORM 4
<TEXT>
<XML>
<?xml version="1.0"?>
<ownershipDocument>

    <schemaVersion>X0508</schemaVersion>

    <documentType>4</documentType>

    <periodOfReport>2026-03-05</periodOfReport>

    <issuer>
        <issuerCik>0001816431</issuerCik>
        <issuerName>Quantum-Si Inc</issuerName>
        <issuerTradingSymbol>QSI</issuerTradingSymbol>
    </issuer>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001534980</rptOwnerCik>
            <rptOwnerName>Kummeth Charles R.</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>C/O QUANTUM-SI INCORPORATED</rptOwnerStreet1>
            <rptOwnerStreet2>29 BUSINESS PARK DRIVE</rptOwnerStreet2>
            <rptOwnerCity>BRANFORD</rptOwnerCity>
            <rptOwnerState>CT</rptOwnerState>
            <rptOwnerZipCode>06405</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>true</isDirector>
        </reportingOwnerRelationship>
    </reportingOwner>

    <aff10b5One>false</aff10b5One>

    <nonDerivativeTable>
        <nonDerivativeTransaction>
            <securityTitle>
                <value>Class A Common Stock</value>
            </securityTitle>
            <transactionDate>
                <value>2026-03-05</value>
            </transactionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>P</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionAmounts>
                <transactionShares>
                    <value>500000</value>
                </transactionShares>
                <transactionPricePerShare>
                    <value>0.9196</value>
                    <footnoteId id="F1"/>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>A</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>855000</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </nonDerivativeTransaction>
    </nonDerivativeTable>

    <footnotes>
        <footnote id="F1">Represents the weighted average purchase price per share. The shares were purchased at prices ranging from $0.8906 to $0.9735 per share. Full information regarding the number of shares purchased at each price shall be provided upon request to the staff of the U.S. Securities and Exchange Commission, the Issuer, or a security holder of the Issuer.</footnote>
    </footnotes>

    <ownerSignature>
        <signatureName>/s/ Christian LaPointe, Ph.D., Attorney-in-Fact.</signatureName>
        <signatureDate>2026-03-09</signatureDate>
    </ownerSignature>
</ownershipDocument>
</XML>
</TEXT>
</DOCUMENT>
</SEC-DOCUMENT>
