IONIS PHARMACEUTICALS INC (IONS) Stock Institutional Trading Activity


IONIS PHARMACEUTICALS INC (IONS) position changes reported by tracked institutional filers across multiple SEC 13F reporting periods. Based on recent SEC 13F filings (Q4 2025), investors with some of the largest reported share count changes include Tweedy, Browne Co All Funds (US), Renaissance Technologies LLC, and ARK Invest. Explore insights into buying and selling patterns, position changes, and investment conviction levels to understand institutional trading behavior and market dynamics.

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Portfolio quarterNameTypeQuantityRemainingReported stock balance
Q4 2019ARK InvestBuy19,356216,025$13,050
Q4 2019Renaissance Technologies LLCBuy225,7002,038,711$123,159
Q3 2019ARK InvestBuy38,896196,669$11,782
Q3 2019Renaissance Technologies LLCBuy57,7001,813,011$108,617
Q2 2019ARK InvestSell-7,205157,773$10,140
Q2 2019Renaissance Technologies LLCBuy1,527,5971,755,311$112,814
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 2017ARK InvestBuy120,942127,563$5,128
Q1 2017Renaissance Technologies LLCSell-136,300313,214$12,591
Q4 2016ARK InvestBuy6,6216,621$317
Q4 2016Renaissance Technologies LLCBuy174,700449,514$21,500
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.