JO
SION

John Overdeck’s Sionna Therapeutics SION Stock Holding History

John Overdeck’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 		– Sell
-5,500
Closed -$220K – 5533
2026
Q1 		$220K Sell
5,500
-900
-14% -$34.3K ﹤0.01% 4246
2025
Q4 		$263K Buy
+6,400
New +$243K ﹤0.01% 3640
2025
Q2 		– Sell
-11,715
Closed -$123K – 3645
2025
Q1 		$123K Buy
+11,715
New +$191K ﹤0.01% 2939

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
O
OrbiMed New York $5.4B AUM 163.13% 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

John Overdeck's SION Position: Q2 2026 in Review

John Overdeck sold out of Sionna Therapeutics (SION) in Q2 2026, closing a stake of 5,500 shares — an estimated $220K sold.

John Overdeck first reported a position in SION in Q1 2025 and held it in 3 quarters. The position peaked at $263K in Q4 2025. 146 funds tracked by Wall St. Rank hold SION as of Q2 2026.

  • John Overdeck reported no remaining Sionna Therapeutics position as of Q2 2026 after selling out during the quarter.
  • John Overdeck sold 5,500 Sionna Therapeutics shares in Q2 2026, an estimated $220K.
  • John Overdeck first reported a position in Sionna Therapeutics in Q1 2025 and held it in 3 quarters.
  • John Overdeck's Sionna Therapeutics position peaked at $263K in Q4 2025.
  • 146 funds tracked by Wall St. Rank held Sionna Therapeutics as of Q2 2026.

Based on Two Sigma Investments's 13F filing for Q2 2026, filed 14 Aug 2026.