Sionna Therapeutics, Inc.

SION·NASDAQ·$42.88Share Price as of 11/2·$2BMarket Cap as of 11/2

Financials

10-QQ2 ended 06/30/2608/06/26 10-QQ1 ended 03/31/2605/12/26 10-KFY 202503/02/26 10-QQ3 ended 09/30/2511/05/25 10-QQ2 ended 06/30/2508/11/25

Disclosures

8-KCurrent report09/14/26 8-KCurrent report08/10/26 8-KCurrent report08/06/26 8-KCurrent report06/18/26 8-KCurrent report05/12/26

Prospectuses and Registrations

S-3ASRAutomatic shelf registration03/02/26 S-8Registration of securities for employees03/02/26 424B4Prospectus02/07/25 S-8Registration of securities for employees02/07/25 S-1MEFProspectus / registration02/06/25

Proxies

DEF 14ADefinitive proxy04/27/26 DEFA14AAdditional proxy materials04/27/26 DEF 14ADefinitive proxy04/29/25 DEFA14AAdditional proxy materials04/29/25

Ownership

Form 4Insider transaction09/21/26 SC 13D/ABeneficial ownership (amended)09/21/26 Form 4Insider transaction09/18/26 Form 4Insider transaction09/18/26 Form 4Insider transaction09/18/26

Other

ARSAnnual report to shareholders04/27/26 ARSAnnual report to shareholders04/29/25 CERTCEO/CFO certification02/06/25 EFFECTRequest for effectiveness02/06/25 SEC STAFF LETTERSEC staff letter02/06/25