<SEC-DOCUMENT>0001959173-25-003201.txt : 20250515
<SEC-HEADER>0001959173-25-003201.hdr.sgml : 20250515
<ACCEPTANCE-DATETIME>20250515102500
ACCESSION NUMBER:		0001959173-25-003201
CONFORMED SUBMISSION TYPE:	144
PUBLIC DOCUMENT COUNT:		1
FILED AS OF DATE:		20250515
DATE AS OF CHANGE:		20250515

SUBJECT COMPANY:	

	COMPANY DATA:	
		COMPANY CONFORMED NAME:			REPLIGEN CORP
		CENTRAL INDEX KEY:			0000730272
		STANDARD INDUSTRIAL CLASSIFICATION:	BIOLOGICAL PRODUCTS (NO DIAGNOSTIC SUBSTANCES) [2836]
		ORGANIZATION NAME:           	03 Life Sciences
		EIN:				042729386
		STATE OF INCORPORATION:			DE
		FISCAL YEAR END:			1231

	FILING VALUES:
		FORM TYPE:		144
		SEC ACT:		1933 Act
		SEC FILE NUMBER:	000-14656
		FILM NUMBER:		25949736

	BUSINESS ADDRESS:	
		STREET 1:		41 SEYON STREET
		STREET 2:		BUILDING 1, SUITE 100
		CITY:			WALTHAM
		STATE:			MA
		ZIP:			02453
		BUSINESS PHONE:		7814499560

	MAIL ADDRESS:	
		STREET 1:		41 SEYON STREET
		STREET 2:		BUILDING 1, SUITE 100
		CITY:			WALTHAM
		STATE:			MA
		ZIP:			02453

REPORTING-OWNER:	

	COMPANY DATA:	
		COMPANY CONFORMED NAME:			Hunt Anthony
		CENTRAL INDEX KEY:			0001606030
		ORGANIZATION NAME:           	

	FILING VALUES:
		FORM TYPE:		144

	MAIL ADDRESS:	
		STREET 1:		41 SEYON STREET
		STREET 2:		BUILDING 1, SUITE 100
		CITY:			WALTHAM
		STATE:			MA
		ZIP:			02452
</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:com="http://www.sec.gov/edgar/common">
  <headerData>
    <submissionType>144</submissionType>
    <filerInfo>
      <filer>
        <filerCredentials>
          <cik>0001606030</cik>
          <ccc>XXXXXXXX</ccc>
        </filerCredentials>
      </filer>
      <liveTestFlag>LIVE</liveTestFlag>



    </filerInfo>
  </headerData>
  <formData>
    <issuerInfo>
      <issuerCik>0000730272</issuerCik>
      <issuerName>REPLIGEN CORP</issuerName>
      <secFileNumber>000-14656</secFileNumber>
      <issuerAddress>
        <com:street1>41 SEYON STREET</com:street1>
        <com:street2>BUILDING 1, SUITE 100</com:street2>
        <com:city>WALTHAM</com:city>
        <com:stateOrCountry>MA</com:stateOrCountry>
        <com:zipCode>02453</com:zipCode>
      </issuerAddress>
      <issuerContactPhone>7814499560</issuerContactPhone>
      <nameOfPersonForWhoseAccountTheSecuritiesAreToBeSold>Hunt Anthony</nameOfPersonForWhoseAccountTheSecuritiesAreToBeSold>
      <relationshipsToIssuer>
        <relationshipToIssuer>Director</relationshipToIssuer>
      </relationshipsToIssuer>
    </issuerInfo>
    <securitiesInformation>
      <securitiesClassTitle>Common</securitiesClassTitle>
      <brokerOrMarketmakerDetails>
        <name>Fidelity Brokerage Services LLC</name>
        <address>
          <com:street1>900 Salem Street</com:street1>
          <com:city>Smithfield</com:city>
          <com:stateOrCountry>RI</com:stateOrCountry>
          <com:zipCode>02917</com:zipCode>
        </address>
      </brokerOrMarketmakerDetails>
      <noOfUnitsSold>26447</noOfUnitsSold>
      <aggregateMarketValue>3394207.98</aggregateMarketValue>
      <noOfUnitsOutstanding>56183100</noOfUnitsOutstanding>
      <approxSaleDate>05/15/2025</approxSaleDate>
      <securitiesExchangeName>NASDAQ</securitiesExchangeName>
    </securitiesInformation>
    <securitiesToBeSold>
      <securitiesClassTitle>Common</securitiesClassTitle>
      <acquiredDate>02/27/2022</acquiredDate>
      <natureOfAcquisitionTransaction>Restricted Stock Vesting</natureOfAcquisitionTransaction>
      <nameOfPersonfromWhomAcquired>Issuer</nameOfPersonfromWhomAcquired>
      <isGiftTransaction>N</isGiftTransaction>
      <amountOfSecuritiesAcquired>3440</amountOfSecuritiesAcquired>
      <paymentDate>02/27/2022</paymentDate>
      <natureOfPayment>Compensation</natureOfPayment>
    </securitiesToBeSold>
    <securitiesToBeSold>
      <securitiesClassTitle>Common</securitiesClassTitle>
      <acquiredDate>02/27/2023</acquiredDate>
      <natureOfAcquisitionTransaction>Restricted Stock Vesting</natureOfAcquisitionTransaction>
      <nameOfPersonfromWhomAcquired>Issuer</nameOfPersonfromWhomAcquired>
      <isGiftTransaction>N</isGiftTransaction>
      <amountOfSecuritiesAcquired>3447</amountOfSecuritiesAcquired>
      <paymentDate>02/27/2023</paymentDate>
      <natureOfPayment>Compensation</natureOfPayment>
    </securitiesToBeSold>
    <securitiesToBeSold>
      <securitiesClassTitle>Common</securitiesClassTitle>
      <acquiredDate>02/24/2024</acquiredDate>
      <natureOfAcquisitionTransaction>Restricted Stock Vesting</natureOfAcquisitionTransaction>
      <nameOfPersonfromWhomAcquired>Issuer</nameOfPersonfromWhomAcquired>
      <isGiftTransaction>N</isGiftTransaction>
      <amountOfSecuritiesAcquired>5442</amountOfSecuritiesAcquired>
      <paymentDate>02/24/2024</paymentDate>
      <natureOfPayment>Compensation</natureOfPayment>
    </securitiesToBeSold>
    <securitiesToBeSold>
      <securitiesClassTitle>Common</securitiesClassTitle>
      <acquiredDate>02/29/2024</acquiredDate>
      <natureOfAcquisitionTransaction>Restricted Stock Vesting</natureOfAcquisitionTransaction>
      <nameOfPersonfromWhomAcquired>Issuer</nameOfPersonfromWhomAcquired>
      <isGiftTransaction>N</isGiftTransaction>
      <amountOfSecuritiesAcquired>1393</amountOfSecuritiesAcquired>
      <paymentDate>02/29/2024</paymentDate>
      <natureOfPayment>Compensation</natureOfPayment>
    </securitiesToBeSold>
    <securitiesToBeSold>
      <securitiesClassTitle>Common</securitiesClassTitle>
      <acquiredDate>03/01/2024</acquiredDate>
      <natureOfAcquisitionTransaction>Restricted Stock Vesting</natureOfAcquisitionTransaction>
      <nameOfPersonfromWhomAcquired>Issuer</nameOfPersonfromWhomAcquired>
      <isGiftTransaction>N</isGiftTransaction>
      <amountOfSecuritiesAcquired>9128</amountOfSecuritiesAcquired>
      <paymentDate>03/01/2024</paymentDate>
      <natureOfPayment>Compensation</natureOfPayment>
    </securitiesToBeSold>
    <securitiesToBeSold>
      <securitiesClassTitle>Common</securitiesClassTitle>
      <acquiredDate>03/02/2024</acquiredDate>
      <natureOfAcquisitionTransaction>Restricted Stock Vesting</natureOfAcquisitionTransaction>
      <nameOfPersonfromWhomAcquired>Issuer</nameOfPersonfromWhomAcquired>
      <isGiftTransaction>N</isGiftTransaction>
      <amountOfSecuritiesAcquired>3597</amountOfSecuritiesAcquired>
      <paymentDate>03/02/2024</paymentDate>
      <natureOfPayment>Compensation</natureOfPayment>
    </securitiesToBeSold>
    <nothingToReportFlagOnSecuritiesSoldInPast3Months>N</nothingToReportFlagOnSecuritiesSoldInPast3Months>
    <securitiesSoldInPast3Months>
      <sellerDetails>
        <name>Anthony J. Hunt</name>
        <address>
          <com:street1>41 Seyon Street, Bldg. 1</com:street1>
          <com:street2>Suite 100</com:street2>
          <com:city>Waltham</com:city>
          <com:stateOrCountry>MA</com:stateOrCountry>
          <com:zipCode>02453</com:zipCode>
        </address>
      </sellerDetails>
      <securitiesClassTitle>Common</securitiesClassTitle>
      <saleDate>03/17/2025</saleDate>
      <amountOfSecuritiesSold>26756</amountOfSecuritiesSold>
      <grossProceeds>4080701.81</grossProceeds>
    </securitiesSoldInPast3Months>
    <noticeSignature>
      <noticeDate>05/15/2025</noticeDate>
      <planAdoptionDates>
        <planAdoptionDate>12/09/2024</planAdoptionDate>
      </planAdoptionDates>
      <signature>/s/ Margaret Campbell, as a duly authorized representative of Fidelity Brokerage Services LLC, as attorney-in-fact for Anthony J. Hunt</signature>
    </noticeSignature>
  </formData>
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</TEXT>
</DOCUMENT>
</SEC-DOCUMENT>
