Sionna Therapeutics, Inc. (SION) Institutional Ownership

Institutions by Trading Activity

Ownership Statistics

15,134,047Shares Outstanding

15,187,723Shares held by institutions

$577,589,106Value of institutional holdings

283.64%Institutional ownership %

2.73%Shares Changed QoQ

96No. of institutional investors

Shares Owned by Institutions

Shares Purchased/Sold by Institutions

Ownership Summary

According to SEC filings for the period ending December 2025, Sionna Therapeutics, Inc. (NASDAQ:SION) is held by 96 institutional firms.

The collective stake of institutional investors in Sionna Therapeutics moved to 283.6% in December 2025, a shift up from the 283.1% reported for September 2025.
Quarterly data indicates a 2.73% shift in institutional share volume, and the annual owner count reflects an unavailable change.
A review of institutional activity for Sionna Therapeutics shows 64 of 96 filers increasing their positions, while 20 reduced their stake, and 12 remained unchanged.
This class of investors increased its holdings in Sionna Therapeutics to 42.93Mn shares for the 13F-cycle ending December 2025, up by 1.14Mn shares quarter on quarter, and down N/A shares year over year.
With 9.91Mn shares, RA CAPITAL MANAGEMENT, L.P. commands the largest institutional position in Sionna Therapeutics as of December 31, 2025, equating to 65.45% of the company.
Among the most significant buyers of Sionna Therapeutics during December 2025 were CITADEL ADVISORS LLC (1.05Mn), EVENTIDE ASSET MANAGEMENT, LLC (639.04K), STATE STREET CORP (453.20K), BlackRock, Inc. (446.99K), Kalehua Capital Management LLC (197.07K).
Leading sellers of Sionna Therapeutics stock in December 2025 included JPMORGAN CHASE & CO (746.81K), Atlas Venture Life Science Advisors, LLC (619.92K), RA CAPITAL MANAGEMENT, L.P. (540.28K), Soleus Capital Management, L.P. (145.00K), ORBIMED ADVISORS LLC (143.30K).
The top 10 institutional holders of Sionna Therapeutics for the quarter ending December 2025 included RA CAPITAL MANAGEMENT, L.P. (9.91Mn), TPG GP A, LLC (6.74Mn), ORBIMED ADVISORS LLC (3.56Mn), VIKING GLOBAL INVESTORS LP (3.20Mn), Atlas Venture Life Science Advisors, LLC (3.00Mn), Enavate Sciences GP, LLC (2.48Mn), BlackRock, Inc. (1.29Mn), JPMORGAN CHASE & CO (1.23Mn), VANGUARD GROUP INC (1.18Mn), PERCEPTIVE ADVISORS LLC (1.18Mn).

96 Institutional Holders

15,187,723 Total Shares Held

Rows:

Download Data

Owner Name	Date	Shares Held	Change (QoQ)	Change (%)	Value (USD)
RA CAPITAL MANAGEMENT, L.P.	31 Dec, 2025	9,905,045	-540,277	-5.17%	$407,493,551.00
TPG GP A, LLC	31 Dec, 2025	6,744,962	0	0.00%	$277,487,737.00
ORBIMED ADVISORS LLC	31 Dec, 2025	3,561,655	-143,304	-3.87%	$146,526,487.00
VIKING GLOBAL INVESTORS LP	31 Dec, 2025	3,195,181	0	0.00%	$131,449,746.00
Atlas Venture Life Science Advisors, LLC	31 Dec, 2025	2,995,602	-619,925	-17.15%	$123,239,066.00
Enavate Sciences GP, LLC	31 Dec, 2025	2,478,030	0	0.00%	$101,946,154.00
BlackRock, Inc.	31 Dec, 2025	1,291,599	446,994	52.92%	$53,136,382.00
JPMORGAN CHASE & CO	31 Dec, 2025	1,231,819	-746,807	-37.74%	$50,677,035.00
VANGUARD GROUP INC	31 Dec, 2025	1,184,951	41,797	3.66%	$48,748,883.00
PERCEPTIVE ADVISORS LLC	31 Dec, 2025	1,179,098	0	0.00%	$48,508,092.00
JENNISON ASSOCIATES LLC	31 Dec, 2025	1,115,278	117,903	11.82%	$45,882,536.00
CITADEL ADVISORS LLC	31 Dec, 2025	1,087,325	1,051,402	2,926.82%	$44,732,551.00
DEERFIELD MANAGEMENT COMPANY, L.P.	31 Dec, 2025	970,590	0	0.00%	$39,930,073.00
Aberdeen Group plc	31 Dec, 2025	839,960	-110,587	-11.63%	$34,555,954.00
STATE STREET CORP	31 Dec, 2025	693,395	453,196	188.68%	$28,526,270.00
EVENTIDE ASSET MANAGEMENT, LLC	31 Dec, 2025	639,045	639,045	0.00%	$26,290,311.00
BAKER BROS. ADVISORS LP	31 Dec, 2025	400,000	0	0.00%	$16,456,000.00
GEODE CAPITAL MANAGEMENT, LLC	31 Dec, 2025	380,042	63,478	20.05%	$15,638,406.00
Siren, L.L.C.	31 Dec, 2025	300,000	-25,000	-7.69%	$12,342,000.00
Soleus Capital Management, L.P.	31 Dec, 2025	268,500	-145,000	-35.07%	$11,046,090.00

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