Rock Springs Capital Management’s Dyne Therapeutics DYN Stock Holding History

Rock Springs Capital Management’s Portfolio DYN Stock Details DYN Fund Activity

Bought

Maintained

Sold

Quarter	Market Value	Status	Shares	Change in Stake	Trade Value	Portfolio Weight	Portfolio Position
2026 Q2	$20.9M	Sell	942,154 -30,044	-3%	-$559K	1.02%	32
2026 Q1	$17.6M	Buy	972,198 +59,243	+6%	+$1.02M	1.04%	32
2025 Q4	$17.9M	Buy	912,955 +88,894	+11%	+$1.68M	0.92%	36
2025 Q3	$10.4M	Buy	824,061 +243,063	+42%	+$2.77M	0.61%	52
2025 Q2	$5.53M	Buy	580,998 +56,499	+11%	+$622K	0.34%	62
2025 Q1	$5.49M	Buy	524,499 +49,971	+11%	+$715K	0.31%	62
2024 Q4	$11.2M	Buy	474,528 +13,500	+3%	+$399K	0.43%	58
2024 Q3	$16.6M	Hold	461,028	–	–	0.54%	53
2024 Q2	$16.3M	Buy	461,028 +9,204	+2%	+$267K	0.49%	56
2024 Q1	$12.8M	Buy	+451,824	New	+$10.2M	0.33%	73

Other funds holding DYN

T. Rowe Price Investment Management Baltimore, Maryland $153B AUM 38.14% 1-Year Est. Return

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

Jupiter Topco New York $245B AUM

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

State Street Boston, Massachusetts $3.37T AUM 44.26% 1-Year Est. Return

OAG

Orbis Allan Gray Hamilton, Bermuda $29.1B AUM 60.8% 1-Year Est. Return

AVLSA

Atlas Venture Life Science Advisors Cambridge, Massachusetts $881M AUM 160.77% 1-Year Est. Return

Vanguard Capital Management Malvern, Pennsylvania $4.68T AUM

TCM

TCG Crossover Management Palo Alto, California $4.16B AUM 983.43% 1-Year Est. Return

Vanguard Portfolio Management Malvern, Pennsylvania $2.22T AUM

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

Rock Springs Capital Management reduced its Dyne Therapeutics (DYN) stake by 3.1% in Q2 2026, selling an estimated $559K and leaving 942,154 shares worth $20.9M. The position accounts for 1.02% of the portfolio, ranked #32.

Rock Springs Capital Management first reported a position in DYN in Q1 2024 and has held it in 10 quarters since. 246 funds tracked by Wall St. Rank hold DYN as of Q2 2026.

Rock Springs Capital Management held 942,154 shares of Dyne Therapeutics worth $20.9M as of Q2 2026.
Rock Springs Capital Management sold 30,044 Dyne Therapeutics shares in Q2 2026, an estimated $559K.
Dyne Therapeutics made up 1.02% of Rock Springs Capital Management's portfolio in Q2 2026, its #32 holding.
Rock Springs Capital Management first reported a position in Dyne Therapeutics in Q1 2024 and has held it in 10 quarters since.
246 funds tracked by Wall St. Rank held Dyne Therapeutics as of Q2 2026.

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