Atlas Venture Fund XI, L.P.

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

Symbol: SION on Nasdaq
Investment type: Equity / Common Stock, $0.001 par value per share
Latest Disclosed Shares Owned: 2,382,495 shares
Security Ownership %: 5.4%

Atlas Venture Fund XI, L.P. ownership in Sionna Therapeutics, Inc. Common Stock, $0.001 par value per share (SION)

20 Oct 2025 - Atlas Venture Fund XI, L.P. has filed an SCHEDULE 13D/A form with the Securities and Exchange Commission (SEC) disclosing ownership of 2,382,495 shares of Sionna Therapeutics, Inc. Common Stock, $0.001 par value per share (SION). This represents 5.4% ownership of the company. In their previous filing dated 18 Feb 2025, Atlas Venture Fund XI, L.P. had reported owning 2,886,293 shares, indicating a decrease of +17%. .

Reporting Name	Ownership %	Change	Value $	Shares owned	Change	Activity %	Price	Form	Report date	Filing time
Atlas Venture Fund XI, L.P.	5.4%	-16%	$74,744,824	2,382,495	-503,798	-17%	$31.37	13D/A	16 Oct 2025	20 Oct 2025, 21:40
Atlas Venture Fund XI, L.P.	6.5%		$34,750,968	2,886,293			$12.04	13D	10 Feb 2025	18 Feb 2025, 16:59