<SEC-DOCUMENT>0001104659-25-041682.txt : 20250430
<SEC-HEADER>0001104659-25-041682.hdr.sgml : 20250430
<ACCEPTANCE-DATETIME>20250430060754
ACCESSION NUMBER:		0001104659-25-041682
CONFORMED SUBMISSION TYPE:	SCHEDULE 13D/A
PUBLIC DOCUMENT COUNT:		1
FILED AS OF DATE:		20250430
DATE AS OF CHANGE:		20250430

SUBJECT COMPANY:	

	COMPANY DATA:	
		COMPANY CONFORMED NAME:			SINOVAC BIOTECH LTD
		CENTRAL INDEX KEY:			0001084201
		STANDARD INDUSTRIAL CLASSIFICATION:	PHARMACEUTICAL PREPARATIONS [2834]
		ORGANIZATION NAME:           	03 Life Sciences
		EIN:				000000000
		STATE OF INCORPORATION:			B9
		FISCAL YEAR END:			1231

	FILING VALUES:
		FORM TYPE:		SCHEDULE 13D/A
		SEC ACT:		1934 Act
		SEC FILE NUMBER:	005-79318
		FILM NUMBER:		25890667

	BUSINESS ADDRESS:	
		STREET 1:		NO. 39 SHANGDI XI ROAD
		STREET 2:		HAIDIAN DISTRICT
		CITY:			BEIJING
		STATE:			F4
		ZIP:			100085
		BUSINESS PHONE:		86-10-82890088

	MAIL ADDRESS:	
		STREET 1:		NO. 39 SHANGDI XI ROAD
		STREET 2:		HAIDIAN DISTRICT
		CITY:			BEIJING
		STATE:			F4
		ZIP:			100085

	FORMER COMPANY:	
		FORMER CONFORMED NAME:	NET FORCE SYSTEMS INC
		DATE OF NAME CHANGE:	19991110

FILED BY:		

	COMPANY DATA:	
		COMPANY CONFORMED NAME:			WEIDONG YIN
		CENTRAL INDEX KEY:			0001264738
		ORGANIZATION NAME:           	

	FILING VALUES:
		FORM TYPE:		SCHEDULE 13D/A

	MAIL ADDRESS:	
		STREET 1:		LATHAM& WATKINS
		STREET 2:		200 CLARENDON STREET
		CITY:			BOSTON
		STATE:			MA
		ZIP:			02116
</SEC-HEADER>
<DOCUMENT>
<TYPE>SCHEDULE 13D/A
<SEQUENCE>1
<FILENAME>primary_doc.xml
<TEXT>
<XML>
<?xml version="1.0" encoding="UTF-8"?><edgarSubmission xmlns="http://www.sec.gov/edgar/schedule13D" xmlns:com="http://www.sec.gov/edgar/common">
  <headerData>
    <submissionType>SCHEDULE 13D/A</submissionType>
    <previousAccessionNumber>0001127855-08-000026</previousAccessionNumber>
    <filerInfo>
      <filer>
        <filerCredentials>
          <!-- Field: Pseudo-Tag; ID: Name; Data: WEIDONG YIN -->
          <cik>0001264738</cik>
          <ccc>XXXXXXXX</ccc>
        </filerCredentials>
      </filer>
      <liveTestFlag>LIVE</liveTestFlag>



    </filerInfo>
  </headerData>
  <formData>
    <coverPageHeader>
      <amendmentNo>4</amendmentNo>
      <securitiesClassTitle>Common Shares</securitiesClassTitle>
      <dateOfEvent>04/28/2025</dateOfEvent>
      <previouslyFiledFlag>false</previouslyFiledFlag>
      <issuerInfo>
        <issuerCIK>0001084201</issuerCIK>
        <issuerCUSIP>P8696W104</issuerCUSIP>
        <issuerName>SINOVAC BIOTECH LTD.</issuerName>
        <address>
          <com:street1>No. 39 Shangdi Xi Rd</com:street1>
          <com:street2>Haidian District</com:street2>
          <com:city>Beijing</com:city>
          <com:stateOrCountry>F4</com:stateOrCountry>
          <com:zipCode>100085</com:zipCode>
        </address>
      </issuerInfo>
      <authorizedPersons>
        <notificationInfo>
          <personName>Weidong Yin</personName>
          <personPhoneNum>86-10-8289-0088</personPhoneNum>
          <personAddress>
            <com:street1>No. 39 Shangdi Xi Road</com:street1>
            <com:street2>Haidian District</com:street2>
            <com:city>Beijing</com:city>
            <com:stateOrCountry>F4</com:stateOrCountry>
            <com:zipCode>100085</com:zipCode>
          </personAddress>
        </notificationInfo>
      </authorizedPersons>
    </coverPageHeader>
    <reportingPersons>
      <reportingPersonInfo>
        <reportingPersonCIK>0001264738</reportingPersonCIK>
        <reportingPersonNoCIK>N</reportingPersonNoCIK>
        <reportingPersonName>Weidong Yin</reportingPersonName>
        <memberOfGroup>b</memberOfGroup>
        <fundType>PF</fundType>
        <legalProceedings>N</legalProceedings>
        <citizenshipOrOrganization>F4</citizenshipOrOrganization>
        <soleVotingPower>6359500.00</soleVotingPower>
        <sharedVotingPower>0.00</sharedVotingPower>
        <soleDispositivePower>6359500.00</soleDispositivePower>
        <sharedDispositivePower>0.00</sharedDispositivePower>
        <aggregateAmountOwned>6359500.00</aggregateAmountOwned>
        <isAggregateExcludeShares>N</isAggregateExcludeShares>
        <percentOfClass>8.85</percentOfClass>
        <typeOfReportingPerson>IN</typeOfReportingPerson>
        <commentContent>Comments to item 13: Calculation is based on 71,860,702 Common Shares of the Issuer outstanding as of March 31, 2024 according to the Issuer's annual report on Form 20-F for the fiscal year ended December 31, 2023 (the "2023 Annual Report").</commentContent>
      </reportingPersonInfo>
    </reportingPersons>
    <items1To7>
      <item1>
        <securityTitle>Common Shares</securityTitle>
        <issuerName>SINOVAC BIOTECH LTD.</issuerName>
        <issuerPrincipalAddress>
          <com:street1>No. 39 Shangdi Xi Rd</com:street1>
          <com:street2>Haidian District</com:street2>
          <com:city>Beijing</com:city>
          <com:stateOrCountry>F4</com:stateOrCountry>
          <com:zipCode>100085</com:zipCode>
        </issuerPrincipalAddress>
        <commentText>This Amendment No.4 to Schedule 13D is being filed on behalf of Weidong Yin (the "Reporting Person"), to amend the Schedule 13D relating to the common shares, par value $0.001 per share (the "Common Shares"), of Sinovac Biotech Ltd. (the "Issuer"), filed by the Reporting Person on February 7, 2008, as amended by Amendment No.1 to Schedule 13D filed on February 8, 2016, Amendment No.2 to Schedule 13D filed on June 27, 2017, and Amendment No.3 to Schedule 13D filed on March 21, 2025 (collectively, the "Original Schedule 13D"). The information in each Item below amends the information disclosed under the corresponding Item of the Original Schedule 13D. Except as amended and supplemented herein, the information set forth in the Original Schedule 13D remains unchanged. Capitalized terms used herein have meanings as assigned thereto in the Original Schedule 13D unless defined herein. The information set forth in response to each separate Item below shall be deemed to be a response to all Items where such information is relevant.</commentText>
      </item1>
      <item4>
        <transactionPurpose>Item 4 is hereby amended and supplemented to add the following:

On April 28, 2025, Cede &amp; Co., as nominee of the Depository Trust Company, submitted a new requisition to the board of directors (the "Board") of the Issuer (the "Requisition") at the request of SAIF Partners IV L.P. ("SAIF"), demanding to convene a special shareholders' meeting of the Issuer for the purposes of, among other things, nominating a few persons, including the Reporting Person, to the Board. Before this Requisition was submitted, SAIF discussed with the Reporting Person the proposal to nominate the Reporting Person to the Board. The Reporting Person and SAIF have not reached any agreement on cooperation.

Except as set forth in this statement, the Reporting Person has no present plan or intention which would result in or relate to any of the transactions described in clauses (a) through (j) of Item 4 of Schedule 13D. The Reporting Person anticipates that further communications may occur with SAIF and other shareholders regarding the Requisition. Depending upon, among other things, the outcome of these communications, the financial condition, results of operations and prospects of the Issuer, conditions in the securities markets, general economic conditions and other factors that the Reporting Person deem relevant, the Reporting Person may take steps and pursue other plans or proposals that relate to or would result in any of the matters set forth in clauses (a) through (j) of Item 4 of Schedule 13D.</transactionPurpose>
      </item4>
      <item6>
        <contractDescription>Item 6 is hereby amended and supplemented to add the following:

Item 4 of Amendment No. 4 is incorporated herein by reference.</contractDescription>
      </item6>
    </items1To7>
    <signatureInfo>
      <signaturePerson>
        <signatureReportingPerson>Weidong Yin</signatureReportingPerson>
        <signatureDetails>
          <signature>/s/ Weidong Yin</signature>
          <title>Weidong Yin</title>
          <date>04/29/2025</date>
        </signatureDetails>
      </signaturePerson>
    </signatureInfo>
  </formData>
</edgarSubmission>
</XML>
</TEXT>
</DOCUMENT>
</SEC-DOCUMENT>
