Sionna Therapeutics, Inc. Common Stock

SION • NASDAQ

Sionna Therapeutics, Inc. Common Stock is a publicly traded company on NASDAQ, with a market cap of $1.9B. As of Q3 2025, 97% of shares are held by 78 institutional investors, with RA CAPITAL MANAGEMENT, LLC as the largest holder at 23.66%.

Market Cap$1.9B

Websitesionnatx.com

Overview

Overview of institutional ownership in SION as of Q3 2025 with a market cap of $1.3B

All Institutions

Institutions: 78
Value Held: $1.3B
Shares Held: 42.8M
Avg Position: $16.2M
Median Position: $739.7K

Hedge Funds

Hedge Funds: 18
Value Held: $630.4M
Shares Held: 21.4M
Avg Position: $35.0M
Median Position: $5.9M

Ownership Breakdown

Institutional (non-HF)

48.5%

$629.6M

Hedge Funds

48.56%

$630.4M

Retail & Other

2.94%

$38.2M

Based on market cap of $1.3B as of Q3 2025. Institutional (non-HF) excludes hedge funds to avoid double counting.

Biggest Investors

Institutions with the largest positions in SION as of Q3 2025

Institution	Key People	Position Value	Ownership	Owned Since	Total AUM (Long)
RA CAPITAL MANAGEMENT, LLC Hedge Fund•Long/Short	Michael Saulnier CFO	$307.2M 3.82% of portfolio	23.66% 10.4M shares	Q1 2025 Held for 8 months	$8.1B
T TPG GP A, LLC Institution	-	$198.4M 10.80% of portfolio	15.28% 6.7M shares	Q1 2025 Held for 8 months	$1.8B
ORBIMED ADVISORS LLC Hedge Fund•Sector	Sam Block Iii CFO	$109.0M 2.64% of portfolio	8.39% 3.7M shares	Q1 2025 Held for 8 months	$4.1B
A Atlas Venture Life Science Advisors, LLC Institution	-	$106.3M 14.13% of portfolio	8.19% 3.6M shares	Q1 2025 Held for 8 months	$752.6M
VIKING GLOBAL INVESTORS LP Hedge Fund•Long/Short	Ole Andreas Halvorsen CEO	$94.0M 0.24% of portfolio	7.24% 3.2M shares	Q1 2025 Held for 8 months	$38.5B
E Enavate Sciences GP, LLC Institution	-	$72.9M 22.25% of portfolio	5.61% 2.5M shares	Q1 2025 Held for 8 months	$327.5M
JPMORGAN CHASE & CO Institution	Jamie Dimon CEO	$58.2M 0.00% of portfolio	4.48% 2.0M shares	Q1 2025 Held for 8 months	$1.56T
PERCEPTIVE ADVISORS LLC Hedge Fund•Long/Short	Joseph Eric Edelman CEO	$34.7M 1.00% of portfolio	2.67% 1.2M shares	Q1 2025 Held for 8 months	$3.5B
VANGUARD GROUP INC Institution	Salim Ramji CEO	$33.6M 0.00% of portfolio	2.59% 1.1M shares	Q1 2025 Held for 8 months	$6.69T
JENNISON ASSOCIATES LLC Long Only Manager	Jeffrey Todd Becker CEO	$29.3M 0.02% of portfolio	2.26% 997.4K shares	Q1 2025 Held for 8 months	$171.73B

Net Capital Flow

Institutional buying and selling activity for SION in Q3 2025

Traded: −$14.7M
Buyers: 39
Sellers: 25
Total Bought: +$47.3M
Total Sold: −$62.0M
Avg Position: $15.0M

Biggest Buyers

Institution	Net Bought	Current Position
VANGUARD GROUP INC Institution	+$15.1M +512.8K shares	$33.6M 1.1M shares
JENNISON ASSOCIATES LLC Long Only Manager	+$7.2M +244.6K shares	$29.3M 997.4K shares
B BlackRock, Inc. Institution	+$6.1M +207.5K shares	$24.8M 844.6K shares
MILLENNIUM MANAGEMENT LLC Hedge Fund•Multi-Strategy	+$5.9M +200.1K shares	$6.3M 214.1K shares
STATE STREET CORP Institution	+$3.4M +115.7K shares	$7.1M 240.2K shares
L Longaeva Partners L.P. Institution	+$1.8M +61.5K shares	$1.8M 61.5K shares
WELLINGTON MANAGEMENT CO LLP Long Only Manager	+$1.2M +42.2K shares	$1.2M 42.2K shares
Soleus Capital Management, L.P. Hedge Fund•Long/Short	+$1.1M +37.5K shares	$12.2M 413.5K shares
T TD ASSET MANAGEMENT INC Institution	+$1.1M +37.1K shares	$2.6M 87.1K shares
Marshall Wace LLP Institution	+$885.3K +30.1K shares	$885.3K 30.1K shares

Biggest Sellers

Institution	Net Sold	Current Position
B BRAIDWELL LP Hedge Fund•Multi-Strategy	−$22.6M −767.8K shares	$9.2M 314.0K shares
FRANKLIN RESOURCES INC Institution	−$7.6M −257.9K shares	$7.1M 242.1K shares
JPMORGAN CHASE & CO Institution	−$7.1M −242.6K shares	$58.2M 2.0M shares
PRICE T ROWE ASSOCIATES INC /MD/ Long Only Manager	−$6.6M −223.5K shares	$18.8M 637.8K shares
CITADEL ADVISORS LLC Hedge Fund•Multi-Strategy	−$2.8M −94.0K shares	$1.1M 35.9K shares
AMERIPRISE FINANCIAL INC Institution	−$2.5M −83.7K shares	$4.5M 153.2K shares
PRUDENTIAL FINANCIAL INC Institution	−$2.3M −135.2K shares	Sold Off 0 shares
A Atlas Venture Life Science Advisors, LLC Institution	−$2.3M −78.5K shares	$106.3M 3.6M shares
SILVERARC CAPITAL MANAGEMENT, LLC Hedge Fund•Long/Short	−$2.3M −77.2K shares	$3.2M 108.8K shares
Woodline Partners LP Hedge Fund•Long/Short	−$1.4M −80.0K shares	Sold Off 0 shares

Entry and Exit Activity

Institutions that initiated new positions or completely exited SION in Q3 2025

New Positions: 16
New Value: $3.9M
Exited Positions: 6
Exited Value: $4.6M

New Positions

Institution	Position Value
L Longaeva Partners L.P. Institution	$1.8M 61.5K shares
WELLINGTON MANAGEMENT CO LLP Long Only Manager	$1.2M 42.2K shares
Jain Global LLC Hedge Fund•Multi-Strategy	$250.4K 8.5K shares
INTECH INVESTMENT MANAGEMENT LLC Long Only Manager	$220.2K 7.5K shares
C China Universal Asset Management Co., Ltd. Institution	$147.1K 5.0K shares
T Tower Research Capital LLC Institution	$132.1K 4.5K shares
R Russell Investments Group, Ltd. RIA/Wealth	$30.1K 1.0K shares
FMR LLC Institution	$6.9K 234.0 shares
GAMMA Investing LLC Long Only Manager	$4.5K 153.0 shares
FEDERATED INVESTORS INC /PA/ Long Only Manager	$3.3K 113.0 shares

Exited Positions

Institution	Previous Position
PRUDENTIAL FINANCIAL INC Institution	$2.3M 135.2K shares
Woodline Partners LP Hedge Fund•Long/Short	$1.4M 80.0K shares
O OPTIONS SOLUTIONS, LLC Hedge Fund•Sector	$294.5K 17.0K shares
SUSQUEHANNA INTERNATIONAL GROUP, LLP Private Equity	$257.4K 14.8K shares
COMMONWEALTH EQUITY SERVICES, LLC. RIA/Wealth	$243.2K 14.0K shares
S STRS OHIO Institution	$39.9K 2.3K shares

Options Activity

Institutions with the largest Call and Put options positions in SION as of Q3 2025

Call Positions: 0
Call Value: -
Put Positions: 0
Put Value: -

Call Positions

Institution	Position Value
No call positions found

Put Positions

Institution	Position Value
No put positions found

Most Committed Institutions

Institutions with SION as the highest % of their portfolio as of Q3 2025

Institution	Key People	Portfolio Weight	Ownership	Owned Since	Total AUM (Long)
E Enavate Sciences GP, LLC Institution	-	22.25% $72.9M	5.61% 2.5M shares	Q1 2025 Held for 8 months	$327.5M
A Atlas Venture Life Science Advisors, LLC Institution	-	14.13% $106.3M	8.19% 3.6M shares	Q1 2025 Held for 8 months	$752.6M
T TPG GP A, LLC Institution	-	10.80% $198.4M	15.28% 6.7M shares	Q1 2025 Held for 8 months	$1.8B
RA CAPITAL MANAGEMENT, LLC Hedge Fund•Long/Short	Michael Saulnier CFO	3.82% $307.2M	23.66% 10.4M shares	Q1 2025 Held for 8 months	$8.1B
ORBIMED ADVISORS LLC Hedge Fund•Sector	Sam Block Iii CFO	2.64% $109.0M	8.39% 3.7M shares	Q1 2025 Held for 8 months	$4.1B
PERCEPTIVE ADVISORS LLC Hedge Fund•Long/Short	Joseph Eric Edelman CEO	1.00% $34.7M	2.67% 1.2M shares	Q1 2025 Held for 8 months	$3.5B
Soleus Capital Management, L.P. Hedge Fund•Long/Short	Guy Bezalel Levy CIO	0.66% $12.2M	0.94% 413.5K shares	Q1 2025 Held for 8 months	$1.8B
DEERFIELD MANAGEMENT CO /NY Hedge Fund•Long/Short	James Edward Flynn President	0.47% $28.5M	2.20% 970.6K shares	Q1 2025 Held for 8 months	$6.0B
SILVERARC CAPITAL MANAGEMENT, LLC Hedge Fund•Long/Short	Devesh Sharad Gandhi Founder	0.46% $3.2M	0.25% 108.8K shares	Q1 2025 Held for 8 months	$689.7M
S Siren, L.L.C. Institution	-	0.40% $9.6M	0.74% 325.0K shares	Q1 2025 Held for 8 months	$2.4B

Hedge Fund Spotlight

Discover hedge funds investing in SION

Soleus Capital Management, L.P.

Hedge Fund • Long/Short

Portfolio ManagerGuy Bezalel Levy

Portfolio Value: $1.8B
Positions: 85
Last Reported: Q3 2025

Sector Allocation

Position in Sionna Therapeutics, Inc. Common Stock

Market Value: $12.2M
Shares Held: 413.5K
Portfolio Weight: 0.66%
Owned Since: 2025-Q1

Top Holding	Sector	Market Value	Weight
1 Krystal Biotech, Inc. KRYS	Biotechnology Healthcare	$179.9M	9.82%
2 TG Therapeutics TGTX	Biotechnology Healthcare	$138.9M	7.59%
3 NovoCure NVCR	Medical - Instruments & Supplies Healthcare	$124.6M	6.81%