Rock Springs Capital Management’s Insmed INSM Stock Holding History

Rock Springs Capital 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	$38.6M	Buy	362,150 +47,850	+15%	+$5.79M	1.88%	12
2026 Q1	$51.4M	Sell	314,300 -4,950	-2%	-$761K	3.03%	7
2025 Q4	$55.6M	Sell	319,250 -65,750	-17%	-$12M	2.85%	9
2025 Q3	$55.4M	Sell	385,000 -140,000	-27%	-$17.2M	3.24%	8
2025 Q2	$52.8M	Buy	525,000 +9,100	+2%	+$696K	3.29%	5
2025 Q1	$39.4M	Sell	515,900 -34,100	-6%	-$2.61M	2.25%	14
2024 Q4	$38M	Sell	550,000 -133,344	-20%	-$9.6M	1.45%	23
2024 Q3	$49.9M	Sell	683,344 -125,012	-15%	-$9.23M	1.62%	21
2024 Q2	$54.2M	Buy	+808,356	New	+$31.4M	1.63%	20
2020 Q1	–	Sell	-800,000	Closed	-$19.1M	–	135
2019 Q4	$19.1M	Sell	800,000 -90,000	-10%	-$1.83M	0.6%	65
2019 Q3	$15.7M	Hold	890,000	–	–	0.63%	56
2019 Q2	$22.8M	Buy	890,000 +40,000	+5%	+$1.11M	0.82%	48
2019 Q1	$24.7M	Hold	850,000	–	–	0.95%	34
2018 Q4	$11.2M	Sell	850,000 -40,000	-4%	-$638K	0.53%	61
2018 Q3	$18M	Buy	890,000 +65,000	+8%	+$1.47M	0.65%	52
2018 Q2	$19.5M	Hold	825,000	–	–	0.75%	43
2018 Q1	$18.6M	Buy	825,000 +211,500	+34%	+$5.57M	0.79%	45
2017 Q4	$19.1M	Sell	613,500 -36,500	-6%	-$1.08M	0.87%	37
2017 Q3	$20.3M	Buy	650,000 +182,000	+39%	+$3.47M	0.94%	34
2017 Q2	$8.03M	Hold	468,000	–	–	0.41%	73
2017 Q1	$8.2M	Hold	468,000	–	–	0.47%	67
2016 Q4	$6.19M	Sell	468,000 -35,000	-7%	-$477K	0.41%	69
2016 Q3	$7.3M	Buy	503,000 +5,500	+1%	+$68.8K	0.46%	63
2016 Q2	$4.91M	Buy	497,500 +47,500	+11%	+$554K	0.36%	83
2016 Q1	$5.7M	Buy	450,000 +17,500	+4%	+$230K	0.48%	71
2015 Q4	$7.85M	Buy	432,500 +67,500	+18%	+$1.19M	0.59%	60
2015 Q3	$6.78M	Hold	365,000	–	–	0.55%	65
2015 Q2	$8.91M	Hold	365,000	–	–	0.65%	54
2015 Q1	$7.59M	Buy	+365,000	New	+$6.43M	0.71%	50

Other funds holding INSM

Fidelity Investments Boston, Massachusetts $2.3T AUM 54.33% 1-Year Est. Return

BlackRock New York $6.73T AUM 46.02% 1-Year Est. Return

Vanguard Portfolio Management Malvern, Pennsylvania $2.22T AUM

JP Morgan Chase New York $1.81T AUM 41.13% 1-Year Est. Return

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 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 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

Rock Springs Capital Management's INSM Position: Q2 2026 in Review

Rock Springs Capital Management increased its Insmed (INSM) stake by 15% in Q2 2026, buying an estimated $5.79M and bringing the position to 362,150 shares worth $38.6M. The position accounts for 1.88% of the portfolio, ranked #12.

Rock Springs Capital Management first reported a position in INSM in Q1 2015 and has held it in 29 quarters since. The position peaked at $55.6M in Q4 2025. 666 funds tracked by Wall St. Rank hold INSM as of Q2 2026.

Rock Springs Capital Management held 362,150 shares of Insmed worth $38.6M as of Q2 2026.
Rock Springs Capital Management bought 47,850 Insmed shares in Q2 2026, an estimated $5.79M.
Insmed made up 1.88% of Rock Springs Capital Management's portfolio in Q2 2026, its #12 holding.
Rock Springs Capital Management first reported a position in Insmed in Q1 2015 and has held it in 29 quarters since.
Rock Springs Capital Management's Insmed position peaked at $55.6M in Q4 2025.
666 funds tracked by Wall St. Rank held Insmed as of Q2 2026.

Based on Rock Springs Capital Management's 13F filing for Q2 2026, filed 14 Aug 2026.