INSMED INC (INSM) Institutional Shareholders
INSMED INC (INSM) is currently reported in institutional portfolios tracked by InsiderSet based on the latest available SEC Form 13F filings for the quarter ended March 31, 2026. The institutional investors covered on this page collectively reported approximately $29.75B in INSM holdings during the latest filing period.
Blackrock, Inc. is currently the largest disclosed institutional shareholder of INSM tracked by InsiderSet, reporting ownership valued at approximately $2.73B in its March 31, 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 $1.64B, representing an estimated loss of -39.70% since the filing period.
The top 10 institutional shareholders tracked on this page collectively account for approximately 53% of the total disclosed INSM value among the investors covered in this analysis. Major shareholders include Blackrock, Inc., Darwin Global Management, Ltd., Fmr Llc, and several other long-term asset managers with concentrated positions in INSMED INC (INSM).
This page ranks the largest institutional INSM 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
651
Total Reported Value
$29.75B
Largest Holder
Blackrock, Inc.
Largest Position
$2.73B
Insider Transactions (90d)
35
Latest Filing Quarter
Q2 2026
New Institutional Positions
63
Funds Exiting Positions
0
| Name | Investor/Manager | Portfolio % | Quantity | Reported Balance | Current Estimated Value | Gain/loss Since Filing | Estimated Portfolio Performance |
|---|---|---|---|---|---|---|---|
| Blackrock, Inc. | 0.05% | 16,678,146 | $2,727,210,442 | $1,644,465,196 | -$1,082,745,246 | -39.70% | |
| Darwin Global Management, Ltd. | 68.33% | 16,805,184 | $2,576,570,811 | $1,656,991,142 | -$919,579,669 | -35.69% | |
| Fmr Llc | 0.11% | 13,160,167 | $2,151,950,430 | $1,297,592,466 | -$854,357,964 | -39.70% | |
| Vanguard Portfolio Management Llc | 0.09% | 10,371,802 | $1,695,997,063 | $1,022,659,677 | -$673,337,386 | -39.70% | |
| Vanguard Capital Management Llc | 0.04% | 9,642,131 | $1,576,681,262 | $950,714,117 | -$625,967,145 | -39.70% | |
| Baker Bros. Advisors Lp | 6.97% | 7,421,111 | $1,213,500,071 | $731,721,545 | -$481,778,526 | -39.70% | |
| Artisan Partners Limited Partnership | 1.74% | 6,527,301 | $1,067,344,315 | $643,591,879 | -$423,752,436 | -39.70% | |
| D. E. Shaw & Co., Inc. | 0.72% | 5,625,825 | $919,934,904 | $554,706,345 | -$365,228,559 | -39.70% | |
| Capital International Investors | 0.21% | 5,595,194 | $914,890,382 | $551,686,128 | -$363,204,254 | -39.70% | |
| State Street Corp | 0.03% | 5,551,699 | $907,813,820 | $547,397,521 | -$360,416,299 | -39.70% | |
| Rtw Investments, Lp | 7.88% | 4,842,880 | $791,907,738 | $477,507,968 | -$314,399,770 | -39.70% | |
| Geode Capital Management, Llc | 0.05% | 4,450,389 | $733,323,353 | $438,808,355 | -$294,514,998 | -40.16% | |
| Ameriprise Financial Inc | 0.12% | 3,057,718 | $499,999,046 | $301,490,995 | -$198,508,051 | -39.70% | |
| Franklin Resources Inc | 0.10% | 2,617,251 | $427,972,899 | $258,060,949 | -$169,911,950 | -39.70% | |
| Citadel Advisors Llc | 0.25% | 2,182,571 | $356,894,010 | $215,201,501 | -$141,692,509 | -39.70% | |
| Invesco Ltd. | 0.05% | 1,988,968 | $325,236,138 | $196,112,245 | -$129,123,893 | -39.70% | |
| Orbis Allan Gray Ltd | 1.29% | 1,872,824 | $306,244,181 | $184,660,446 | -$121,583,735 | -39.70% | |
| Ubs Group Ag | 0.05% | 1,737,481 | $284,112,894 | $171,315,627 | -$112,797,267 | -39.70% | |
| Bank Of America Corp | 0.02% | 1,502,281 | $245,652,979 | $148,124,907 | -$97,528,072 | -39.70% | |
| Integral Health Asset Management, Llc | 12.98% | 1,500,000 | $245,280,000 | $147,900,000 | -$97,380,000 | -39.70% | |
| Westfield Capital Management Co Lp | 1.01% | 1,468,459 | $240,122,429 | $144,790,057 | -$95,332,372 | -39.70% | |
| Sei Investments Co | 0.21% | 1,395,794 | $228,239,457 | $137,625,288 | -$90,614,169 | -39.70% | |
| Capital World Investors | 0.03% | 1,362,291 | $222,743,856 | $134,321,893 | -$88,421,963 | -39.70% | |
| Vanguard Fiduciary Trust Co | 0.06% | 1,354,516 | $221,490,456 | $133,555,278 | -$87,935,178 | -39.70% | |
| Morgan Stanley | 0.01% | 1,331,542 | $217,734,151 | $131,290,041 | -$86,444,110 | -39.70% | |
| Northern Trust Corp | 0.03% | 1,294,000 | $211,594,881 | $127,588,400 | -$84,006,481 | -39.70% | |
| Castle Hook Partners Lp | 4.20% | 1,269,754 | $207,630,174 | $125,197,744 | -$82,432,430 | -39.70% | |
| Bank Of New York Mellon Corp | 0.04% | 1,262,749 | $206,484,758 | $124,507,051 | -$81,977,707 | -39.70% | |
| Paradigm Biocapital Advisors Lp | 4.19% | 1,254,488 | $205,133,878 | $123,692,517 | -$81,441,361 | -39.70% | |
| Ubs Am, A Distinct Business Unit Of Ubs Asset Management Americas Llc | 0.04% | 1,215,025 | $198,680,888 | $119,801,465 | -$78,879,423 | -39.70% | |
| Millennium Management Llc | 0.14% | 1,157,786 | $189,321,167 | $114,157,700 | -$75,163,467 | -39.70% | |
| Nomura Asset Management International Inc. | 0.32% | 1,143,739 | $187,024,000 | $112,772,665 | -$74,251,335 | -39.70% | |
| Charles Schwab Investment Management Inc | 0.03% | 1,069,390 | $174,866,653 | $105,441,854 | -$69,424,799 | -39.70% | |
| Fiera Capital Corp | 0.57% | 1,021,970 | $167,112,534 | $100,766,242 | -$66,346,292 | -39.70% | |
| Goldman Sachs Group Inc | 0.02% | 942,646 | $154,141,406 | $92,944,896 | -$61,196,510 | -39.70% | |
| American Century Companies Inc | 0.08% | 925,799 | $151,387,667 | $91,283,781 | -$60,103,886 | -39.70% | |
| Principal Financial Group Inc | 0.08% | 916,464 | $149,860,193 | $90,363,350 | -$59,496,843 | -39.70% | |
| William Blair Investment Management, Llc | 0.49% | 902,666 | $147,603,944 | $89,002,868 | -$58,601,076 | -39.70% | |
| Adage Capital Partners Gp, L.L.C. | 0.23% | 900,000 | $147,168,000 | $88,740,000 | -$58,428,000 | -39.70% | |
| Fil Ltd | 0.11% | 828,947 | $135,549,413 | $81,734,174 | -$53,815,239 | -39.70% | |
| Amundi | 0.04% | 804,977 | $131,629,839 | $79,370,732 | -$52,259,107 | -39.70% | |
| Pictet Asset Management Holding Sa | 0.12% | 1,220,353 | $129,804,038 | $120,326,806 | -$9,477,232 | -7.30% | |
| Legal & General Group Plc | 0.03% | 787,079 | $128,703,161 | $77,605,989 | -$51,097,172 | -39.70% | |
| Alliancebernstein L.P. | 0.04% | 688,734 | $119,867,265 | $67,909,172 | -$51,958,093 | -43.35% | |
| Hood River Capital Management Llc | 1.13% | 688,554 | $112,592,350 | $67,891,424 | -$44,700,926 | -39.70% | |
| Aqr Capital Management Llc | 0.05% | 675,481 | $108,786,345 | $66,602,427 | -$42,183,918 | -38.78% | |
| Summit Partners Public Asset Management, Llc | 5.06% | 653,445 | $106,851,326 | $64,429,677 | -$42,421,649 | -39.70% | |
| Clearbridge Investments, Llc | 0.09% | 643,435 | $105,214,441 | $63,442,691 | -$41,771,750 | -39.70% | |
| Artia Global Partners Lp | 23.18% | 628,712 | $102,806,986 | $61,991,003 | -$40,815,983 | -39.70% | |
| Swiss National Bank | 0.06% | 625,912 | $102,349,130 | $61,714,923 | -$40,634,207 | -39.70% |
Frequently asked questions about INSM
Who owns the most INSM stock?
The largest holders of INSM 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 INSMED INC (INSM).
Is INSM widely held by superinvestors?
Many widely followed stocks like INSM appear across numerous superinvestor portfolios because of liquidity, index inclusion, and fundamentals. The holder count and table above show how broadly INSM 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.