<SEC-DOCUMENT>0001422849-25-000016.txt : 20250213
<SEC-HEADER>0001422849-25-000016.hdr.sgml : 20250213
<ACCEPTANCE-DATETIME>20250213165314
ACCESSION NUMBER:		0001422849-25-000016
CONFORMED SUBMISSION TYPE:	SCHEDULE 13G
PUBLIC DOCUMENT COUNT:		1
FILED AS OF DATE:		20250213
DATE AS OF CHANGE:		20250213

SUBJECT COMPANY:	

	COMPANY DATA:	
		COMPANY CONFORMED NAME:			IONIS PHARMACEUTICALS INC
		CENTRAL INDEX KEY:			0000874015
		STANDARD INDUSTRIAL CLASSIFICATION:	PHARMACEUTICAL PREPARATIONS [2834]
		ORGANIZATION NAME:           	03 Life Sciences
		IRS NUMBER:				330336973
		STATE OF INCORPORATION:			CA
		FISCAL YEAR END:			1231

	FILING VALUES:
		FORM TYPE:		SCHEDULE 13G
		SEC ACT:		1934 Act
		SEC FILE NUMBER:	005-41771
		FILM NUMBER:		25621208

	BUSINESS ADDRESS:	
		STREET 1:		2855 GAZELLE COURT
		CITY:			CARLSBAD
		STATE:			CA
		ZIP:			92010
		BUSINESS PHONE:		7609319200

	MAIL ADDRESS:	
		STREET 1:		2855 GAZELLE COURT
		CITY:			CARLSBAD
		STATE:			CA
		ZIP:			92010

	FORMER COMPANY:	
		FORMER CONFORMED NAME:	ISIS PHARMACEUTICALS INC
		DATE OF NAME CHANGE:	19930328

FILED BY:		

	COMPANY DATA:	
		COMPANY CONFORMED NAME:			Capital World Investors
		CENTRAL INDEX KEY:			0001422849
		ORGANIZATION NAME:           	
		IRS NUMBER:				951411037
		STATE OF INCORPORATION:			DE
		FISCAL YEAR END:			0630

	FILING VALUES:
		FORM TYPE:		SCHEDULE 13G

	BUSINESS ADDRESS:	
		STREET 1:		333 SOUTH HOPE STREET
		STREET 2:		55TH FLOOR
		CITY:			LOS ANGELES
		STATE:			CA
		ZIP:			90071
		BUSINESS PHONE:		213-486-9200

	MAIL ADDRESS:	
		STREET 1:		333 SOUTH HOPE STREET
		STREET 2:		55TH FLOOR
		CITY:			LOS ANGELES
		STATE:			CA
		ZIP:			90071
</SEC-HEADER>
<DOCUMENT>
<TYPE>SCHEDULE 13G
<SEQUENCE>1
<FILENAME>primary_doc.xml
<TEXT>
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  <headerData>
    <submissionType>SCHEDULE 13G</submissionType>
    <filerInfo>
      <filer>
        <filerCredentials>
          <cik>0001422849</cik>
          <ccc>XXXXXXXX</ccc>
        </filerCredentials>
      </filer>
      <liveTestFlag>LIVE</liveTestFlag>



    </filerInfo>
  </headerData>
  <formData>
    <coverPageHeader>
      <securitiesClassTitle>Common Stock</securitiesClassTitle>
      <eventDateRequiresFilingThisStatement>12/31/2024</eventDateRequiresFilingThisStatement>
      <issuerInfo>
        <issuerCik>0000874015</issuerCik>
        <issuerName>Ionis Pharmaceuticals, Inc.</issuerName>
        <issuerCusip>462222100</issuerCusip>
        <issuerPrincipalExecutiveOfficeAddress>
          <com:street1>2855 Gazelle Court</com:street1>
          <com:city>Carlsbad</com:city>
          <com:stateOrCountry>X1</com:stateOrCountry>
          <com:zipCode>92010</com:zipCode>
        </issuerPrincipalExecutiveOfficeAddress>
      </issuerInfo>
      <designateRulesPursuantThisScheduleFiled>
        <designateRulePursuantThisScheduleFiled>Rule 13d-1(b)</designateRulePursuantThisScheduleFiled>
      </designateRulesPursuantThisScheduleFiled>
    </coverPageHeader>
    <coverPageHeaderReportingPersonDetails>

      <reportingPersonName>Capital World Investors</reportingPersonName>
      <citizenshipOrOrganization>DE</citizenshipOrOrganization>
      <reportingPersonBeneficiallyOwnedNumberOfShares>
        <soleVotingPower>11465413</soleVotingPower>
        <sharedVotingPower>0</sharedVotingPower>
        <soleDispositivePower>11465413</soleDispositivePower>
        <sharedDispositivePower>0</sharedDispositivePower>
      </reportingPersonBeneficiallyOwnedNumberOfShares>
      <reportingPersonBeneficiallyOwnedAggregateNumberOfShares>11465413.00</reportingPersonBeneficiallyOwnedAggregateNumberOfShares>
      <classPercent>7.3</classPercent>
      <typeOfReportingPerson>IA</typeOfReportingPerson>
    </coverPageHeaderReportingPersonDetails>
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      <item1>
        <issuerName>Ionis Pharmaceuticals, Inc.</issuerName>
        <issuerPrincipalExecutiveOfficeAddress>2855 Gazelle Court, Carlsbad, CA 92010, United States of America</issuerPrincipalExecutiveOfficeAddress>
      </item1>
      <item2>
        <filingPersonName>Capital World Investors</filingPersonName>
        <principalBusinessOfficeOrResidenceAddress>333 SOUTH HOPE STREET, 55TH FLOOR, LOS ANGELES, CALIFORNIA  90071
</principalBusinessOfficeOrResidenceAddress>
        <citizenship>N/A</citizenship>
      </item2>
      <item3>
        <notApplicableFlag>N</notApplicableFlag>
        <typeOfPersonFiling>IA</typeOfPersonFiling>
      </item3>
      <item4>
        <amountBeneficiallyOwned>11,465,413 **

**Capital World Investors ("CWI") is a division of Capital Research and Management Company ("CRMC"), as well as its investment management subsidiaries and affiliates Capital Bank and Trust Company, Capital International, Inc., Capital International Limited, Capital International Sarl, Capital International K.K., Capital Group Private Client Services, Inc., and Capital Group Investment Management Private Limited (together with CRMC, the "investment management entities"). CWI's divisions of each of the investment management entities collectively provide investment management services under the name "Capital World Investors." CWI is deemed to be the beneficial owner of 11,465,413 shares or 7.3% of the 157,897,287 shares believed to be outstanding.</amountBeneficiallyOwned>
        <classPercent>7.3</classPercent>
        <numberOfSharesPersonHas>
          <solePowerOrDirectToVote>11,465,413</solePowerOrDirectToVote>
          <sharedPowerOrDirectToVote>0</sharedPowerOrDirectToVote>
          <solePowerOrDirectToDispose>11,465,413</solePowerOrDirectToDispose>
          <sharedPowerOrDirectToDispose>0</sharedPowerOrDirectToDispose>
        </numberOfSharesPersonHas>
      </item4>
      <item5>
        <notApplicableFlag>Y</notApplicableFlag>
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      <item6>
        <notApplicableFlag>Y</notApplicableFlag>
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      <item9>
        <notApplicableFlag>Y</notApplicableFlag>
      </item9>
      <item10>
        <notApplicableFlag>N</notApplicableFlag>
        <certifications>By signing below I certify that, to the best of my knowledge and belief, the securities referred to above were acquired and are held in the ordinary course of business and were not acquired and are not held for the purpose of or with the effect of changing or influencing the control of the issuer of the securities and were not acquired and are not held in connection with or as a participant in any transaction having that purpose or effect, other than activities solely in connection with a nomination under ?? 240.14a-11.</certifications>
      </item10>
    </items>
    <signatureInformation>
      <reportingPersonName>Capital World Investors</reportingPersonName>
      <signatureDetails>
        <signature>Jae Won Chung</signature>
        <title>Vice President and Senior Counsel II, Capital Research and Management Company</title>
        <date>02/12/2025</date>
      </signatureDetails>
    </signatureInformation>
  </formData>
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</SEC-DOCUMENT>
