Sionna Therapeutics, Inc. - Common Stock, $0.001 par value per share (SION)

Q: What does CUSIP 829401108 represent in this 13F holders report?

CUSIP 829401108 is the security identifier for SION - Sionna Therapeutics, Inc. - Common Stock, $0.001 par value per share used to aggregate holder disclosures.

Q: How many institutions held SION - Sionna Therapeutics, Inc. - Common Stock, $0.001 par value per share in Q3 2026?

8 institutional investors reported SION - Sionna Therapeutics, Inc. - Common Stock, $0.001 par value per share for Q3 2026. Use the holders table for investor-level position and value details.

CUSIP: 829401108

Q3 2026 13F Holders as of 30 Sep 2026

Security type / class: Equity / Common Stock, $0.001 par value per share
Total 13F shares: 1,079,041
Total 13F value: $5,675,557
Share change: +1,078,580
SEC-reported price per share: $5.26
Number of holders: 8
Value change: +$5,672,550
Number of buys: 7
Number of sells: 1
Shares outstanding: 45,288,063

Security key

829401108

Report period

Q3 2026

Institutions

Top holders

SION full security history Ownership snapshot Full 13F holder table Previous quarter: Q1 2026 Sionna Therapeutics, Inc. SEC filings Sionna Therapeutics, Inc. company facts

Broader feeds

Latest 13F filings Latest 13D/G filings Investors directory

Reporting periods

Holder history for CUSIP 829401108

Previous quarter: Q1 2026

Recent filing periods:

Q3 2026 Q1 2026 Q4 2025 Q3 2025

Ownership snapshot

Top reported holders of SION - Sionna Therapeutics, Inc. - Common Stock, $0.001 par value per share (13F + 13D/G + 3/4/5)

Grouped by holder across the latest SEC ownership disclosures. Start with comparable ownership when available, then verify the linked 13F, 13D/G, or 3/4/5 evidence.

Comparable stake leader

TPG GP A, LLC

Disclosed value leader

RA CAPITAL MANAGEMENT, L.P.

Comparable rows

8/15

Latest evidence

17 Sep 2026

13F 13D/G 3/4/5 Lead comparable stake: 15% 7 rows are not safely comparable across share classes. 13D/G row: TPG GP A, LLC Showing 1-6 of 15 holder rows.

Quick read

TPG GP A, LLC leads the comparable SEC ownership view at 15%.

8 of 15 rows have a safely comparable ownership percentage. Use this as a filing-backed starting point, then open the detailed table for source links, reporting role, position value, share count, and filing date.

Open SEC evidence Opens TPG GP A, LLC's linked filing trail.

Comparable ownership Top 5

TPG GP A, LLC 15%

RA CAPITAL MANAGEMENT, L.P. 14%

VIKING GLOBAL INVESTORS LP 7.1%

ORBIMED ADVISORS LLC 6.6%

Enavate Sciences GP, LLC 5.6%

Ownership % is shown only when SEC disclosures are safely comparable across share classes.

Detailed SEC evidence table Showing 1-6 of 15 holder rows

Holder	Evidence	Ownership %	Position	12M Net Δ	As of
TPG GP A, LLC	13F 13D/G 3/4/5 Company · 10%+ Owner 13F 13D/G 3/4/5	15% Reported 13D/G · 10 Feb 2025	$285,713,378 6,494,962 shares	—	30 Jun 2026
RA CAPITAL MANAGEMENT, L.P.	13F 13D/G 3/4/5 Company · Director, 10%+ Owner 13F 13D/G 3/4/5	14% Reported 13D/G · 17 Sep 2026	$435,722,930 9,905,045 shares	—	30 Jun 2026
VIKING GLOBAL INVESTORS LP	13F 13D/G Company 13F 13D/G	7.1% Reported 13D/G · 31 Mar 2026	$140,556,012 3,195,181 shares	—	30 Jun 2026
ORBIMED ADVISORS LLC	13D/G 3/4/5 13F Director · Company 13D/G 3/4/5 13F	6.6% Reported 13D/G · 15 Apr 2026	$118,970,633 2,967,722 shares	-$29,554,504	15 Apr 2026
Enavate Sciences GP, LLC	13F 13D/G Company 13F 13D/G	5.6% Reported 13D/G · 10 Feb 2025	$109,008,540 2,478,030 shares	—	30 Jun 2026
Atlas Venture Fund XI, L.P.	13D/G 3/4/5 10%+ Owner 13D/G 3/4/5	5.4% Reported 13D/G · 16 Oct 2025	$74,744,824 2,382,495 shares	-$15,805,403	16 Oct 2025

How to read this table

Rows are grouped by holder and ranked first by SEC-reported ownership % when it is safely comparable, then by disclosed holdings value. — indicates unavailable or non-comparable values; "mixed-class rows" means the latest filing spans non-comparable classes.

13F holder rows

Institutional holders as of Q3 2026

Investor-level positions for this CUSIP, loaded as an interactive table.

Institutions

1,079,041

Rows available

Investor	Option	Weight %	Change %	SEC-reported value	* Price	Shares	Share Change	Activity	Report Period

^* SEC-reported price is the security price as of the portfolio date and can indicate the last known price at which the security was still held. The marker flags a reported price that did not pass the local price check.

Compare Q3 2026 vs Q1 2026 Across Filers

Q1 2026 holders

121

Q3 2026 holders

Holder diff

-113

Investor	Q1 2026 Shares	Q3 2026 Shares	Share Diff	Share Chg %	Q1 2026 value	Q3 2026 value	Value change	Value Chg %

Trend: ostatnie 8 kwartałów (+ wybrane okresy porównania).

Quarterly Holders Trend

Quarterly Value Trend

Quarterly Shares Trend