<SEC-DOCUMENT>0000950170-25-074751.txt : 20250519
<SEC-HEADER>0000950170-25-074751.hdr.sgml : 20250519
<ACCEPTANCE-DATETIME>20250519201900
ACCESSION NUMBER:		0000950170-25-074751
CONFORMED SUBMISSION TYPE:	144
PUBLIC DOCUMENT COUNT:		1
FILED AS OF DATE:		20250519
DATE AS OF CHANGE:		20250519

SUBJECT COMPANY:	

	COMPANY DATA:	
		COMPANY CONFORMED NAME:			Klaviyo, Inc.
		CENTRAL INDEX KEY:			0001835830
		STANDARD INDUSTRIAL CLASSIFICATION:	SERVICES-PREPACKAGED SOFTWARE [7372]
		ORGANIZATION NAME:           	06 Technology
		EIN:				000000000
		STATE OF INCORPORATION:			DE
		FISCAL YEAR END:			1231

	FILING VALUES:
		FORM TYPE:		144
		SEC ACT:		1933 Act
		SEC FILE NUMBER:	001-41806
		FILM NUMBER:		25965862

	BUSINESS ADDRESS:	
		STREET 1:		125 SUMMER STREET, FLOOR 6
		CITY:			BOSTON
		STATE:			MA
		ZIP:			02110
		BUSINESS PHONE:		800-338-1744

	MAIL ADDRESS:	
		STREET 1:		125 SUMMER STREET, FLOOR 6
		CITY:			BOSTON
		STATE:			MA
		ZIP:			02110

REPORTING-OWNER:	

	COMPANY DATA:	
		COMPANY CONFORMED NAME:			Summit Partners Growth Equity Fund IX-B, L.P.
		CENTRAL INDEX KEY:			0001634426
		ORGANIZATION NAME:           	
		EIN:				473155260
		STATE OF INCORPORATION:			DE
		FISCAL YEAR END:			1231

	FILING VALUES:
		FORM TYPE:		144

	BUSINESS ADDRESS:	
		STREET 1:		222 BERKELEY STREET, 18TH FLOOR
		CITY:			BOSTON
		STATE:			MA
		ZIP:			02116
		BUSINESS PHONE:		617-824-1000

	MAIL ADDRESS:	
		STREET 1:		222 BERKELEY STREET, 18TH FLOOR
		CITY:			BOSTON
		STATE:			MA
		ZIP:			02116
</SEC-HEADER>
<DOCUMENT>
<TYPE>144
<SEQUENCE>1
<FILENAME>primary_doc.xml
<TEXT>
<XML>
<?xml version="1.0" encoding="UTF-8"?><edgarSubmission xmlns="http://www.sec.gov/edgar/ownership" xmlns:xsd="http://www.w3.org/2001/XMLSchema" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance">
<headerData>
<submissionType>144</submissionType>
<filerInfo>
<filer>
<filerCredentials>
<cik>0001634426</cik>
<ccc>XXXXXXXX</ccc>
</filerCredentials>
</filer>
<liveTestFlag>LIVE</liveTestFlag>
</filerInfo>
</headerData>
<formData>
<issuerInfo>
<issuerCik>0001835830</issuerCik>
<issuerName>Klaviyo, Inc.</issuerName>
<secFileNumber>001-41806</secFileNumber>
<issuerAddress>
<street1 xmlns="http://www.sec.gov/edgar/common">125 Summer Street, 6th Floor</street1>
<city xmlns="http://www.sec.gov/edgar/common">Boston</city>
<stateOrCountry xmlns="http://www.sec.gov/edgar/common">MA</stateOrCountry>
<zipCode xmlns="http://www.sec.gov/edgar/common">02110</zipCode>
</issuerAddress>
<issuerContactPhone>617-213-1788</issuerContactPhone>
<nameOfPersonForWhoseAccountTheSecuritiesAreToBeSold>Summit Partners Growth Equity Fund IX-B, L.P.</nameOfPersonForWhoseAccountTheSecuritiesAreToBeSold>
<relationshipsToIssuer>
<relationshipToIssuer>Owner</relationshipToIssuer>
</relationshipsToIssuer>
</issuerInfo>
<securitiesInformation>
<securitiesClassTitle>Series A common stock, par value $0.001 per share</securitiesClassTitle>
<brokerOrMarketmakerDetails>
<name>Barclays Capital Inc.</name>
<address>
<street1 xmlns="http://www.sec.gov/edgar/common">745 7th Avenue</street1>
<city xmlns="http://www.sec.gov/edgar/common">New York</city>
<stateOrCountry xmlns="http://www.sec.gov/edgar/common">NY</stateOrCountry>
<zipCode xmlns="http://www.sec.gov/edgar/common">10019</zipCode>
</address>
</brokerOrMarketmakerDetails>
<noOfUnitsSold>1476104</noOfUnitsSold>
<aggregateMarketValue>50925588</aggregateMarketValue>
<noOfUnitsOutstanding>94683729</noOfUnitsOutstanding>
<approxSaleDate>05/19/2025</approxSaleDate>
<securitiesExchangeName>NYSE</securitiesExchangeName>
</securitiesInformation>
<securitiesToBeSold>
<securitiesClassTitle>Series A common stock, par value $0.001 per share</securitiesClassTitle>
<acquiredDate>09/20/2023</acquiredDate>
<natureOfAcquisitionTransaction>Pre-IPO transactions.</natureOfAcquisitionTransaction>
<nameOfPersonfromWhomAcquired>Klaviyo, Inc.</nameOfPersonfromWhomAcquired>
<isGiftTransaction>N</isGiftTransaction>
<amountOfSecuritiesAcquired>20086500</amountOfSecuritiesAcquired>
<paymentDate>09/20/2023</paymentDate>
<natureOfPayment>Equity interests in the Issuer were purchased pre-IPO.</natureOfPayment>
</securitiesToBeSold>
<nothingToReportFlagOnSecuritiesSoldInPast3Months>N</nothingToReportFlagOnSecuritiesSoldInPast3Months>
<securitiesSoldInPast3Months>
<sellerDetails>
<name>Summit Partners Growth Equity Fund IX-B, L.P.</name>
<address>
<street1 xmlns="http://www.sec.gov/edgar/common">222 Berkeley St 18th FL</street1>
<city xmlns="http://www.sec.gov/edgar/common">Boston</city>
<stateOrCountry xmlns="http://www.sec.gov/edgar/common">MA</stateOrCountry>
<zipCode xmlns="http://www.sec.gov/edgar/common">02116</zipCode>
</address>
</sellerDetails>
<securitiesClassTitle>Series A common stock, par value $0.001 per share</securitiesClassTitle>
<saleDate>03/14/2025</saleDate>
<amountOfSecuritiesSold>738052</amountOfSecuritiesSold>
<grossProceeds>23617664</grossProceeds>
</securitiesSoldInPast3Months>
<noticeSignature>
<noticeDate>05/19/2025</noticeDate>
<signature>/s/ Adam Hennessey</signature>
</noticeSignature>
</formData>
</edgarSubmission>
</XML>
</TEXT>
</DOCUMENT>
</SEC-DOCUMENT>
