O
SION

OrbiMed’s Sionna Therapeutics SION Stock Holding History

OrbiMed’s Portfolio SION Stock Details SION Fund Activity
Bought
Maintained
Sold
Quarter Market Value Status Shares Change in
Stake 		Trade Value Portfolio Weight Portfolio Position
2026
Q2 		$112M Sell
2,555,877
-974,825
-28% -$39M 2.08% 8
2026
Q1 		$142M Sell
3,530,702
-30,953
-0.9% -$1.18M 2.81% 8
2025
Q4 		$147M Sell
3,561,655
-143,304
-4% -$5.43M 2.99% 8
2025
Q3 		$109M Hold
3,704,959
– – 2.56% 11
2025
Q2 		$64.3M Hold
3,704,959
– – 1.61% 19
2025
Q1 		$38.8M Buy
+3,704,959
New +$60.5M 0.92% 31

Other funds holding SION

RCM
RA Capital Management Boston, Massachusetts $11.5B AUM 168.77% 1-Year Est. Return
TGA
TPG GP A Fort Worth, Texas $5B AUM 58.56% 1-Year Est. Return
Viking Global Investors
Viking Global Investors Stamford, Connecticut $35.1B AUM 21.36% 1-Year Est. Return
AVLSA
Atlas Venture Life Science Advisors Cambridge, Massachusetts $881M AUM 160.77% 1-Year Est. Return
ES
Enavate Sciences Menlo Park, California $345M AUM 134.64% 1-Year Est. Return
Adage Capital Partners
Adage Capital Partners Boston, Massachusetts $71.3B AUM 56.8% 1-Year Est. Return
BlackRock
BlackRock New York $6.73T AUM 46.02% 1-Year Est. Return
JP Morgan Chase
JP Morgan Chase New York $1.81T AUM 41.13% 1-Year Est. Return
Jennison Associates
Jennison Associates New York $167B AUM 44.17% 1-Year Est. Return
Citadel Advisors
Citadel Advisors Miami, Florida $875B AUM 40.89% 1-Year Est. Return

OrbiMed's SION Position: Q2 2026 in Review

OrbiMed reduced its Sionna Therapeutics (SION) stake by 28% in Q2 2026, selling an estimated $39M and leaving 2,555,877 shares worth $112M. The position accounts for 2.08% of the portfolio, ranked #8.

OrbiMed first reported a position in SION in Q1 2025 and has held it in 6 quarters since. The position peaked at $147M in Q4 2025. 146 funds tracked by Wall St. Rank hold SION as of Q2 2026.

  • OrbiMed held 2,555,877 shares of Sionna Therapeutics worth $112M as of Q2 2026.
  • OrbiMed sold 974,825 Sionna Therapeutics shares in Q2 2026, an estimated $39M.
  • Sionna Therapeutics made up 2.08% of OrbiMed's portfolio in Q2 2026, its #8 holding.
  • OrbiMed first reported a position in Sionna Therapeutics in Q1 2025 and has held it in 6 quarters since.
  • OrbiMed's Sionna Therapeutics position peaked at $147M in Q4 2025.
  • 146 funds tracked by Wall St. Rank held Sionna Therapeutics as of Q2 2026.

Based on OrbiMed's 13F filing for Q2 2026, filed 14 Aug 2026.