IONIS PHARMACEUTICALS INC (IONS) Institutional Ownership Changes & 13F Activity

IONIS PHARMACEUTICALS INC (IONS) institutional ownership data tracks hedge funds, asset managers, and other institutional investors based on recent SEC 13F filings (Q1 2026). This page analyzes institutional buying and selling activity, new holdings, and sold-out positions among tracked filers. Notable filers include Tweedy, Browne Co All Funds (US), ARK Invest, and Renaissance Technologies LLC.

Portfolio quarterNameTypeQuantityRemainingReported stock balance
Q2 2020ARK InvestBuy224,450344,131$20,290
Q2 2020Renaissance Technologies LLCBuy64,4561,752,867$103,349
Q1 2020Renaissance Technologies LLCSell-350,3001,688,411$79,828
Q1 2020ARK InvestSell-96,344119,681$5,659
Q4 2019Renaissance Technologies LLCBuy225,7002,038,711$123,159
Q4 2019ARK InvestBuy19,356216,025$13,050
Q3 2019Renaissance Technologies LLCBuy57,7001,813,011$108,617
Q3 2019ARK InvestBuy38,896196,669$11,782
Q2 2019Renaissance Technologies LLCBuy1,527,5971,755,311$112,814
Q2 2019ARK InvestSell-7,205157,773$10,140
Q1 2019ARK InvestSell-77,334164,978$13,391
Q4 2018ARK InvestBuy12,994242,312$13,099
Q3 2018ARK InvestBuy16,191229,318$11,828
Q2 2018ARK InvestSell-138,778213,127$8,881
Q1 2018Renaissance Technologies LLCBuy145,300227,714$10,038
Q1 2018ARK InvestSell-18,930351,905$15,512
Q4 2017ARK InvestBuy123,372370,835$18,653
Q3 2017ARK InvestBuy70,472247,463$12,546
Q2 2017Renaissance Technologies LLCSell-230,80082,414$4,192
Q2 2017ARK InvestBuy49,428176,991$9,004
Q1 2017Renaissance Technologies LLCSell-136,300313,214$12,591
Q1 2017ARK InvestBuy120,942127,563$5,128
Q4 2016Renaissance Technologies LLCBuy174,700449,514$21,500
Q4 2016ARK InvestBuy6,6216,621$317
Q3 2016Renaissance Technologies LLCBuy91,714274,814$10,069
Q2 2016Renaissance Technologies LLCBuy123,700183,100$4,264
Q1 2016Renaissance Technologies LLCSell-75,91459,400$2,406
Q4 2015Renaissance Technologies LLCBuy135,314135,314$8,380

Frequently asked questions about IONS activity

  • Which institutional owners are buying IONS?

    Institutional owners buying IONS include investors who have either initiated new positions or increased their existing holdings based on recent SEC 13F filings. The activity table above highlights which funds added shares in the latest reporting periods and how their positions changed over time.

  • What does "buy" mean in IONS activity?

    "Buy" means an investor increased their reported position in IONS compared to the prior reporting period. This reflects growing exposure to IONIS PHARMACEUTICALS INC (IONS) rather than necessarily a brand-new position (though new positions also appear as buys when prior quantity was zero).

  • Is institutional interest in IONS increasing?

    Institutional interest in IONS can be assessed by comparing the number of tracked funds adding or increasing positions versus those trimming or exiting across the periods shown. A higher number of additions typically signals increasing participation among large filers, but it should be read alongside position sizes and the full table.

Related IONS insights

IONS Institutional Ownership Changes and 13F Activity Q1 2026 | InsiderSet