IONIS PHARMACEUTICALS INC (IONS) Institutional Shareholders
IONIS PHARMACEUTICALS INC (IONS) is currently reported in institutional portfolios tracked by InsiderSet based on the latest available SEC Form 13F filings for the quarter ended June 30, 2026. The institutional investors covered on this page collectively reported approximately $14.12B in IONS holdings during the latest filing period.
Fmr Llc is currently the largest disclosed institutional shareholder of IONS tracked by InsiderSet, reporting ownership valued at approximately $1.95B in its June 30, 2026 SEC Form 13F filing. Based on current market prices and the latest disclosed share count, the position is now estimated to be worth approximately $1.10B, representing an estimated loss of -43.45% since the filing period.
The top 10 institutional shareholders tracked on this page collectively account for approximately 56% of the total disclosed IONS value among the investors covered in this analysis. Major shareholders include Fmr Llc, Capital World Investors, Blackrock, Inc., and several other long-term asset managers with concentrated positions in IONIS PHARMACEUTICALS INC (IONS).
This page ranks the largest institutional IONS shareholders using publicly disclosed SEC Form 13F data, including reported values, estimated current holding values, portfolio allocation percentages, ownership concentration metrics, and historical holding changes across major hedge funds and investment firms.
Institutional Holders
496
Total Reported Value
$14.12B
Largest Holder
Fmr Llc
Largest Position
$1.95B
Insider Transactions (90d)
24
Latest Filing Quarter
Q2 2026
New Institutional Positions
40
Funds Exiting Positions
0
| Name | Investor/Manager | Portfolio % | Quantity | Reported Balance | Current Estimated Value | Gain/loss Since Filing | Estimated Portfolio Performance |
|---|---|---|---|---|---|---|---|
| Fmr Llc | 0.08% | 24,631,956 | $1,953,067,764 | $1,104,496,907 | -$848,570,857 | -43.45% | |
| Capital World Investors | 0.20% | 21,669,226 | $1,718,152,930 | $971,648,094 | -$746,504,836 | -43.45% | |
| Blackrock, Inc. | 0.01% | 10,704,660 | $848,772,532 | $479,996,954 | -$368,775,578 | -43.45% | |
| Vanguard Portfolio Management Llc | 0.03% | 7,859,529 | $623,182,054 | $352,421,280 | -$270,760,774 | -43.45% | |
| Wellington Management Group Llp | 0.10% | 7,651,415 | $606,680,694 | $343,089,449 | -$263,591,245 | -43.45% | |
| Vanguard Capital Management Llc | 0.01% | 7,211,497 | $571,799,597 | $323,363,525 | -$248,436,072 | -43.45% | |
| Two Sigma Investments, Lp | 0.37% | 6,252,342 | $495,748,197 | $280,355,015 | -$215,393,182 | -43.45% | |
| Royal Bank Of Canada | 0.08% | 6,182,479 | $490,209,000 | $277,222,358 | -$212,986,642 | -43.45% | |
| State Street Corp | 0.01% | 4,334,848 | $343,710,098 | $194,374,584 | -$149,335,514 | -43.45% | |
| T. Rowe Price Investment Management, Inc. | 0.21% | 3,959,372 | $313,939,000 | $177,538,240 | -$136,400,760 | -43.45% | |
| Geode Capital Management, Llc | 0.02% | 3,584,024 | $294,752,810 | $160,707,636 | -$134,045,174 | -45.48% | |
| Price T Rowe Associates Inc | 0.03% | 3,184,500 | $252,500,000 | $142,792,980 | -$109,707,020 | -43.45% | |
| Jpmorgan Chase & Co | 0.01% | 2,671,717 | $216,198,792 | $119,799,790 | -$96,399,002 | -44.59% | |
| Artisan Partners Limited Partnership | 0.34% | 2,640,024 | $209,327,536 | $118,378,676 | -$90,948,860 | -43.45% | |
| Tweedy, Browne Co All Funds (US) | B. Tweedy, Ch. Browne | 13.70% | 2,280,311 | $180,805,859 | $102,249,145 | -$78,556,714 | -43.45% |
| Deep Track Capital, Lp | 2.57% | 2,200,000 | $174,438,000 | $98,648,000 | -$75,790,000 | -43.45% | |
| Goldman Sachs Group Inc | 0.02% | 2,109,945 | $167,297,540 | $94,609,934 | -$72,687,606 | -43.45% | |
| Baker Bros. Advisors Lp | 0.81% | 2,047,727 | $162,364,274 | $91,820,079 | -$70,544,195 | -43.45% | |
| Deerfield Management Company, L.P. | 1.64% | 1,979,669 | $156,967,955 | $88,768,358 | -$68,199,597 | -43.45% | |
| American Century Companies Inc | 0.07% | 1,947,076 | $154,383,816 | $87,306,888 | -$67,076,928 | -43.45% | |
| Charles Schwab Investment Management Inc | 0.02% | 1,605,054 | $127,264,731 | $71,970,621 | -$55,294,110 | -43.45% | |
| Barclays Plc | 0.04% | 1,603,136 | $127,112,653 | $71,884,618 | -$55,228,035 | -43.45% | |
| Pictet Asset Management Holding Sa | 0.12% | 1,596,998 | $126,981,913 | $71,609,390 | -$55,372,523 | -43.61% | |
| Polar Capital Holdings Plc | 0.33% | 1,454,021 | $115,289,325 | $65,198,302 | -$50,091,023 | -43.45% | |
| Alyeska Investment Group, L.P. | 0.29% | 1,417,916 | $112,426,560 | $63,579,353 | -$48,847,207 | -43.45% | |
| Ubs Am, A Distinct Business Unit Of Ubs Asset Management Americas Llc | 0.02% | 1,475,632 | $110,805,207 | $66,167,339 | -$44,637,868 | -40.28% | |
| Nomura Asset Management International Inc. | 0.15% | 1,300,392 | $103,108,000 | $58,309,577 | -$44,798,423 | -43.45% | |
| Morgan Stanley | 0.01% | 1,281,444 | $101,605,768 | $57,459,949 | -$44,145,819 | -43.45% | |
| Invesco Ltd. | 0.01% | 1,120,707 | $88,860,858 | $50,252,502 | -$38,608,356 | -43.45% | |
| Vanguard Fiduciary Trust Co | 0.02% | 1,060,845 | $84,114,400 | $47,568,290 | -$36,546,110 | -43.45% | |
| Bellevue Group Ag | 1.62% | 972,258 | $77,090,336 | $43,596,049 | -$33,494,287 | -43.45% | |
| Groupama Asset Managment | 0.95% | 937,083 | $75,195,315 | $42,018,802 | -$33,176,513 | -44.12% | |
| Northern Trust Corp | 0.01% | 913,610 | $72,440,137 | $40,966,272 | -$31,473,865 | -43.45% | |
| Capital International Investors | 0.01% | 823,764 | $65,316,248 | $36,937,578 | -$28,378,670 | -43.45% | |
| Davern Capital Partners, Lp | 10.80% | 798,709 | $63,329,637 | $35,814,112 | -$27,515,525 | -43.45% | |
| Bank Of America Corp | 0.00% | 790,990 | $62,717,591 | $35,467,992 | -$27,249,599 | -43.45% | |
| Summit Partners Public Asset Management, Llc | 1.62% | 787,263 | $62,422,083 | $35,300,873 | -$27,121,210 | -43.45% | |
| Gw&K Investment Management, Llc | 0.46% | 746,966 | $59,227,000 | $33,493,955 | -$25,733,045 | -43.45% | |
| Bnp Paribas Asset Management Holding S.A. | 0.06% | 734,219 | $58,216,225 | $32,922,380 | -$25,293,845 | -43.45% | |
| Nuveen, Llc | 0.01% | 726,282 | $57,586,900 | $32,566,485 | -$25,020,415 | -43.45% | |
| Connor, Clark & Lunn Investment Management Ltd. | 0.10% | 684,236 | $54,253,072 | $30,681,142 | -$23,571,930 | -43.45% | |
| Eversept Partners, Lp | 2.87% | 664,684 | $52,702,794 | $29,804,431 | -$22,898,363 | -43.45% | |
| Voloridge Investment Management, Llc | 0.22% | 655,454 | $51,970,948 | $29,390,557 | -$22,580,391 | -43.45% | |
| Massachusetts Financial Services Co | 0.02% | 651,816 | $51,682,490 | $29,227,429 | -$22,455,061 | -43.45% | |
| Neuberger Berman Group Llc | 0.03% | 633,533 | $50,232,832 | $28,407,620 | -$21,825,212 | -43.45% | |
| Arrowstreet Capital, Limited Partnership | 0.02% | 632,028 | $50,113,500 | $28,340,136 | -$21,773,364 | -43.45% | |
| Ubs Group Ag | 0.01% | 624,874 | $49,546,260 | $28,019,350 | -$21,526,910 | -43.45% | |
| Timessquare Capital Management, Llc | 0.72% | 614,070 | $48,689,610 | $27,534,899 | -$21,154,711 | -43.45% | |
| Eventide Asset Management, Llc | 0.61% | 575,000 | $45,591,750 | $25,783,000 | -$19,808,750 | -43.45% | |
| Perceptive Advisors Llc | 0.70% | 566,000 | $44,878,140 | $25,379,440 | -$19,498,700 | -43.45% |
Frequently asked questions about IONS
Who owns the most IONS stock?
The largest holders of IONS are typically major institutional investors such as asset managers and hedge funds reporting on Form 13F. The table above ranks tracked superinvestors by reported position size using the latest available filings for IONIS PHARMACEUTICALS INC (IONS).
Is IONS widely held by superinvestors?
Many widely followed stocks like IONS appear across numerous superinvestor portfolios because of liquidity, index inclusion, and fundamentals. The holder count and table above show how broadly IONS is represented among the institutional managers we track.
What do “Current Estimated Value”, “Gain/loss Since Filing”, and “Estimated Portfolio Performance” mean?
Current Estimated Value is reported share quantity from the latest 13F times our most recent split-adjusted U.S. session close. Gain/loss Since Filing is that estimate minus the reported 13F dollar value; Estimated Portfolio Performance is that difference as a percent of the reported value. Green means the estimate is above the filing value; red means below (not purchase cost). If many filers share the same implied filing price per share, the performance % may match across rows. These are not official fund marks or live quotes.