IONS Institutional Ownership & Shareholders
IONIS PHARMACEUTICALS INC (IONS) is currently held by 483 institutional investors tracked by InsiderSet, with a combined reported market value of approximately $14.00B based on the latest available SEC Form 13F filings for the quarter ended June 30, 2026.
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 $1.07B, representing an estimated loss of -45.11% since the filing period.
The top 10 institutional shareholders tracked on this page collectively account for approximately 57% 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
483
Total Reported Value
$14.00B
Largest Holder
Fmr Llc
Largest Position
$1.95B
Insider Transactions (90d)
8
Latest Filing Quarter
Q2 2026
New Institutional Positions
48
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 | $1,071,982,725 | -$881,085,039 | -45.11% | |
| Capital World Investors | 0.20% | 21,669,226 | $1,718,152,930 | $943,044,716 | -$775,108,214 | -45.11% | |
| Blackrock, Inc. | 0.01% | 10,704,660 | $848,772,532 | $465,866,803 | -$382,905,729 | -45.11% | |
| Vanguard Portfolio Management Llc | 0.03% | 7,859,529 | $623,182,054 | $342,046,702 | -$281,135,352 | -45.11% | |
| Wellington Management Group Llp | 0.10% | 7,651,415 | $606,680,694 | $332,989,581 | -$273,691,113 | -45.11% | |
| Vanguard Capital Management Llc | 0.01% | 7,211,497 | $571,799,597 | $313,844,349 | -$257,955,248 | -45.11% | |
| Two Sigma Investments, Lp | 0.37% | 6,252,342 | $495,748,197 | $272,101,924 | -$223,646,273 | -45.11% | |
| Royal Bank Of Canada | 0.08% | 6,182,479 | $490,209,000 | $269,061,486 | -$221,147,514 | -45.11% | |
| State Street Corp | 0.01% | 4,334,848 | $343,710,098 | $188,652,585 | -$155,057,513 | -45.11% | |
| T. Rowe Price Investment Management, Inc. | 0.21% | 3,959,372 | $313,939,000 | $172,311,869 | -$141,627,131 | -45.11% | |
| Geode Capital Management, Llc | 0.02% | 3,584,024 | $294,752,810 | $155,976,724 | -$138,776,086 | -47.08% | |
| Price T Rowe Associates Inc | 0.03% | 3,184,500 | $252,500,000 | $138,589,440 | -$113,910,560 | -45.11% | |
| Jpmorgan Chase & Co | 0.01% | 2,671,717 | $216,198,792 | $116,273,124 | -$99,925,668 | -46.22% | |
| Artisan Partners Limited Partnership | 0.34% | 2,640,024 | $209,327,536 | $114,893,844 | -$94,433,692 | -45.11% | |
| Tweedy, Browne Co All Funds (US) | B. Tweedy, Ch. Browne | 13.70% | 2,280,311 | $180,805,859 | $99,239,135 | -$81,566,724 | -45.11% |
| Deep Track Capital, Lp | 2.57% | 2,200,000 | $174,438,000 | $95,744,000 | -$78,694,000 | -45.11% | |
| Goldman Sachs Group Inc | 0.02% | 2,109,945 | $167,297,540 | $91,824,806 | -$75,472,734 | -45.11% | |
| Baker Bros. Advisors Lp | 0.81% | 2,047,727 | $162,364,274 | $89,117,079 | -$73,247,195 | -45.11% | |
| Deerfield Management Company, L.P. | 1.64% | 1,979,669 | $156,967,955 | $86,155,195 | -$70,812,760 | -45.11% | |
| American Century Companies Inc | 0.07% | 1,947,076 | $154,383,816 | $84,736,748 | -$69,647,068 | -45.11% | |
| Charles Schwab Investment Management Inc | 0.02% | 1,605,054 | $127,264,731 | $69,851,950 | -$57,412,781 | -45.11% | |
| Barclays Plc | 0.04% | 1,603,136 | $127,112,653 | $69,768,479 | -$57,344,174 | -45.11% | |
| Pictet Asset Management Holding Sa | 0.12% | 1,596,998 | $126,981,913 | $69,501,353 | -$57,480,560 | -45.27% | |
| Polar Capital Holdings Plc | 0.33% | 1,454,021 | $115,289,325 | $63,278,994 | -$52,010,331 | -45.11% | |
| Alyeska Investment Group, L.P. | 0.29% | 1,417,916 | $112,426,560 | $61,707,704 | -$50,718,856 | -45.11% | |
| Ubs Am, A Distinct Business Unit Of Ubs Asset Management Americas Llc | 0.02% | 1,475,632 | $110,805,207 | $64,219,505 | -$46,585,702 | -42.04% | |
| Nomura Asset Management International Inc. | 0.15% | 1,300,392 | $103,108,000 | $56,593,060 | -$46,514,940 | -45.11% | |
| Morgan Stanley | 0.01% | 1,281,444 | $101,605,768 | $55,768,443 | -$45,837,325 | -45.11% | |
| Invesco Ltd. | 0.01% | 1,120,707 | $88,860,858 | $48,773,169 | -$40,087,689 | -45.11% | |
| Vanguard Fiduciary Trust Co | 0.02% | 1,060,845 | $84,114,400 | $46,167,974 | -$37,946,426 | -45.11% | |
| Bellevue Group Ag | 1.62% | 972,258 | $77,090,336 | $42,312,668 | -$34,777,668 | -45.11% | |
| Groupama Asset Managment | 0.95% | 937,083 | $75,195,315 | $40,781,852 | -$34,413,463 | -45.77% | |
| Northern Trust Corp | 0.01% | 913,610 | $72,440,137 | $39,760,307 | -$32,679,830 | -45.11% | |
| Capital International Investors | 0.01% | 823,764 | $65,316,248 | $35,850,209 | -$29,466,039 | -45.11% | |
| Davern Capital Partners, Lp | 10.80% | 798,709 | $63,329,637 | $34,759,816 | -$28,569,821 | -45.11% | |
| Bank Of America Corp | 0.00% | 790,990 | $62,717,591 | $34,423,885 | -$28,293,706 | -45.11% | |
| Summit Partners Public Asset Management, Llc | 1.62% | 787,263 | $62,422,083 | $34,261,686 | -$28,160,397 | -45.11% | |
| Gw&K Investment Management, Llc | 0.46% | 746,966 | $59,227,000 | $32,507,960 | -$26,719,040 | -45.11% | |
| Bnp Paribas Asset Management Holding S.A. | 0.06% | 734,219 | $58,216,225 | $31,953,211 | -$26,263,014 | -45.11% | |
| Nuveen, Llc | 0.01% | 726,282 | $57,586,900 | $31,607,793 | -$25,979,107 | -45.11% | |
| Connor, Clark & Lunn Investment Management Ltd. | 0.10% | 684,236 | $54,253,072 | $29,777,951 | -$24,475,121 | -45.11% | |
| Eversept Partners, Lp | 2.87% | 664,684 | $52,702,794 | $28,927,048 | -$23,775,746 | -45.11% | |
| Voloridge Investment Management, Llc | 0.22% | 655,454 | $51,970,948 | $28,525,358 | -$23,445,590 | -45.11% | |
| Massachusetts Financial Services Co | 0.02% | 651,816 | $51,682,490 | $28,367,032 | -$23,315,458 | -45.11% | |
| Arrowstreet Capital, Limited Partnership | 0.02% | 632,028 | $50,113,500 | $27,505,859 | -$22,607,641 | -45.11% | |
| Ubs Group Ag | 0.01% | 624,874 | $49,546,260 | $27,194,516 | -$22,351,744 | -45.11% | |
| Timessquare Capital Management, Llc | 0.72% | 614,070 | $48,689,610 | $26,724,326 | -$21,965,284 | -45.11% | |
| Eventide Asset Management, Llc | 0.61% | 575,000 | $45,591,750 | $25,024,000 | -$20,567,750 | -45.11% | |
| Perceptive Advisors Llc | 0.70% | 566,000 | $44,878,140 | $24,632,320 | -$20,245,820 | -45.11% | |
| Renaissance Technologies LLC | Jim Simons | 0.06% | 559,414 | $44,355,936 | $24,345,697 | -$20,010,239 | -45.11% |
Frequently asked questions about IONS
Who are the largest institutional holders of IONS?
The largest institutional holders of IONS reported in the latest SEC Form 13F filings include Fmr Llc, Capital World Investors, Blackrock, Inc., Vanguard Portfolio Management Llc, and Wellington Management Group Llp. InsiderSet ranks institutional holders by their latest reported IONS position.
What is IONS institutional ownership?
This page tracks IONS positions reported by institutional investment managers through SEC Form 13F. IONIS PHARMACEUTICALS INC (IONS) institutional ownership on InsiderSet reflects disclosed 13F holdings among the managers we analyze, not every shareholder of the stock.
How many institutions own IONS?
InsiderSet currently tracks 483 institutional managers reporting IONS holdings in the latest available 13F data. This count reflects institutions included in the SEC Form 13F filings analyzed by InsiderSet and should not be interpreted as the total number of IONS shareholders.
How much IONS stock do institutions own?
Institutional investment managers disclosed approximately $14.00B in IONS holdings for Q2 2026. This figure is reported 13F value as of the filing period, not necessarily today's market value.
When was IONS institutional ownership last updated?
The latest IONS institutional ownership data on InsiderSet is based on SEC Form 13F filings for the quarter ended June 30, 2026. Form 13F filings are generally reported after the quarter ends, so the holdings shown represent the latest publicly disclosed positions rather than real-time institutional holdings.
Are institutional IONS holdings real-time?
No. Form 13F data is not real-time. It represents positions reported by institutional investment managers as of the end of the reporting quarter. An institution may have changed its IONS position after the reporting date.
Are institutions buying or selling IONS?
Institutional buying and selling can be analyzed by comparing IONS positions across consecutive 13F reporting periods. InsiderSet's IONS Ownership Changes page shows institutions that increased, reduced, initiated, or exited positions based on reported 13F holdings. View IONS ownership changes.
How has IONS institutional ownership changed over time?
InsiderSet tracks IONS institutional holdings across multiple 13F reporting periods, allowing investors to compare institutional holder counts, reported value, and reported shares over time.