William Blair Investment Management
INSM icon

William Blair Investment Management’s Insmed INSM Stock Holding History

William Blair Investment Management’s Portfolio INSM Stock Details INSM Fund Activity
Bought
Maintained
Sold
Quarter Market Value Status Shares Change in
Stake 		Trade Value Portfolio Weight Portfolio Position
2026
Q2 		$67.2M Sell
629,831
-272,835
-30% -$33M 0.2% 132
2026
Q1 		$148M Sell
902,666
-318,430
-26% -$49M 0.49% 54
2025
Q4 		$213M Sell
1,221,096
-333,961
-21% -$60.9M 0.59% 36
2025
Q3 		$224M Sell
1,555,057
-110,545
-7% -$13.5M 0.58% 38
2025
Q2 		$168M Sell
1,665,602
-647,615
-28% -$49.5M 0.44% 68
2025
Q1 		$176M Sell
2,313,217
-120,226
-5% -$9.2M 0.5% 56
2024
Q4 		$168M Buy
2,433,443
+12,535
+0.5% +$903K 0.41% 78
2024
Q3 		$177M Sell
2,420,908
-1,048,820
-30% -$77.4M 0.44% 74
2024
Q2 		$232M Sell
3,469,728
-744,991
-18% -$28.9M 0.61% 38
2024
Q1 		$114M Sell
4,214,719
-41,968
-1% -$1.17M 0.3% 101
2023
Q4 		$132M Buy
4,256,687
+14,752
+0.3% +$383K 0.38% 89
2023
Q3 		$107M Sell
4,241,935
-43,984
-1% -$1.01M 0.36% 90
2023
Q2 		$90.4M Buy
4,285,919
+579,241
+16% +$11M 0.29% 105
2023
Q1 		$63.2M Buy
3,706,678
+316,513
+9% +$6.15M 0.22% 117
2022
Q4 		$67.7M Sell
3,390,165
-166,419
-5% -$3.22M 0.26% 110
2022
Q3 		$76.6M Buy
3,556,584
+29,495
+0.8% +$707K 0.3% 101
2022
Q2 		$69.6M Sell
3,527,089
-68,537
-2% -$1.44M 0.26% 114
2022
Q1 		$84.5M Sell
3,595,626
-1,318,514
-27% -$30.6M 0.25% 116
2021
Q4 		$134M Sell
4,914,140
-61,901
-1% -$1.77M 0.36% 92
2021
Q3 		$137M Sell
4,976,041
-50,143
-1% -$1.32M 0.39% 90
2021
Q2 		$143M Buy
5,026,184
+1,261,948
+34% +$37.5M 0.45% 87
2021
Q1 		$128M Buy
3,764,236
+60,610
+2% +$2.32M 0.42% 92
2020
Q4 		$123M Buy
3,703,626
+1,316,630
+55% +$48.1M 0.41% 90
2020
Q3 		$76.7M Buy
2,386,996
+1,567,605
+191% +$45.1M 0.3% 103
2020
Q2 		$22.6M Buy
819,391
+103,823
+15% +$2.46M 0.09% 181
2020
Q1 		$11.5M Buy
+715,568
New +$17M 0.06% 222

Other funds holding INSM

Fidelity Investments
Fidelity Investments Boston, Massachusetts $2.3T AUM 54.33% 1-Year Est. Return
BlackRock
BlackRock New York $6.73T AUM 46.02% 1-Year Est. Return
Vanguard Portfolio Management
Vanguard Portfolio Management Malvern, Pennsylvania $2.22T AUM
JP Morgan Chase
JP Morgan Chase New York $1.81T AUM 41.13% 1-Year Est. Return
Vanguard Capital Management
Vanguard Capital Management Malvern, Pennsylvania $4.68T AUM
BBA
Baker Bros. Advisors New York $20B AUM 154.41% 1-Year Est. Return
Capital International Investors
Capital International Investors Los Angeles, California $484B AUM 34.9% 1-Year Est. Return
DGM
Darwin Global Management St. Helier, Jersey $3.76B AUM 342.13% 1-Year Est. Return
Ameriprise
Ameriprise Minneapolis, Minnesota $495B AUM 43.24% 1-Year Est. Return
OAG
Orbis Allan Gray Hamilton, Bermuda $29.1B AUM 60.8% 1-Year Est. Return

William Blair Investment Management's INSM Position: Q2 2026 in Review

William Blair Investment Management reduced its Insmed (INSM) stake by 30% in Q2 2026, selling an estimated $33M and leaving 629,831 shares worth $67.2M. The position accounts for 0.2% of the portfolio, ranked #132.

William Blair Investment Management first reported a position in INSM in Q1 2020 and has held it in 26 quarters since. The position peaked at $232M in Q2 2024. 665 funds tracked by Wall St. Rank hold INSM as of Q2 2026.

  • William Blair Investment Management held 629,831 shares of Insmed worth $67.2M as of Q2 2026.
  • William Blair Investment Management sold 272,835 Insmed shares in Q2 2026, an estimated $33M.
  • Insmed made up 0.2% of William Blair Investment Management's portfolio in Q2 2026, its #132 holding.
  • William Blair Investment Management first reported a position in Insmed in Q1 2020 and has held it in 26 quarters since.
  • William Blair Investment Management's Insmed position peaked at $232M in Q2 2024.
  • 665 funds tracked by Wall St. Rank held Insmed as of Q2 2026.

Based on William Blair Investment Management's 13F filing for Q2 2026, filed 12 Aug 2026.