Company Analysis

Sionna Therapeutics, Inc. (SION)

Nasdaq: SION · Pharmaceutical Preparations · Waltham, MA · filing with the SEC since 2024
Grade5.3
◀ Past 4.2● Present 6.8▶ Future 4.6
7 est.

Filings

65 filings since 2017 beside 169 insider forms · Non-accelerated filer and smaller reporting company and emerging growth company · read from EDGAR on Nov 13, 2026
Due nextNon-accelerated filer and smaller reporting company and emerging growth company
10-K Annual report for the fiscal year ending Dec 31, 2026Non-accelerated filers and smaller reporting companies have 90 days after the fiscal year ends. by Mar 31, 2027
10-Q Quarterly report for the quarter ending Mar 31, 2027Non-accelerated filers and smaller reporting companies have 45 days after the quarter ends; quarter ends are taken to the month end. by May 15, 2027

A deadline is the latest date the SEC's rules allow for its filer category. It is not a forecast of the day the company files. Last time, the results release (8-K item 2.02) came 41 days after the quarter ended. The proxy statement was last filed Apr 27, 2026.

Filings a yearinsider forms included
616464
202420252026

2026 counts to Nov 13, 2026.

Officer or director change (8-K item 5.02): 1 time in the last 36 months, the newest Sep 14, 2026.SEC letters: 6 in the last 36 months, the newest Feb 4, 2025.
Insider forms 169

Insider forms (3, 4, 5 and 144) are counted each year but not listed here; the people and their trades are on the Ownership tab.

FiledFormWhat it is, in plain wordsPeriodAsk
Nov 10, 2026 10-Q Quarterly report Sep 30, 2026
Nov 10, 2026 8-K items 2.02, 9.01 Results released · Current report
Nov 9, 2026 SCHEDULE 13G Large holder notice
Sep 21, 2026 SCHEDULE 13D/A Activist holder update, amended
Sep 14, 2026 8-K items 2.05, 5.02, 8.01, 9.01 Exit or restructuring costs; Officer or director change; Other event · Current report Sep 9, 2026
Aug 10, 2026 8-K items 8.01, 9.01 Other event · Current report
Aug 6, 2026 10-Q Quarterly report Jun 30, 2026
Aug 6, 2026 8-K items 2.02, 9.01 Results released · Current report
Jun 18, 2026 8-K item 5.07 Shareholder vote · Current report Jun 17, 2026
May 15, 2026 SCHEDULE 13G/A Large holder update, amended
May 12, 2026 10-Q Quarterly report Mar 31, 2026
May 12, 2026 8-K items 2.02, 9.01 Results released · Current report
May 12, 2026 SCHEDULE 13G/A Large holder update, amended
Apr 27, 2026 ARS Annual report to shareholders Dec 31, 2025
Apr 27, 2026 DEFA14A Extra proxy material
Apr 27, 2026 DEF 14A Proxy statement Jun 17, 2026
Apr 20, 2026 SCHEDULE 13D/A Activist holder update, amended
Mar 2, 2026 10-K Annual report Dec 31, 2025
Mar 2, 2026 8-K items 2.02, 9.01 Results released · Current report
Mar 2, 2026 S-8 Employee stock plan registration
Mar 2, 2026 S-3ASR Shelf registration
Nov 7, 2025 SCHEDULE 13D/A Activist holder update, amended
Nov 5, 2025 10-Q Quarterly report Sep 30, 2025
Nov 5, 2025 8-K items 2.02, 9.01 Results released · Current report
Oct 31, 2025 SCHEDULE 13G/A Large holder update, amended
Oct 20, 2025 SCHEDULE 13D/A Activist holder update, amended
Aug 11, 2025 10-Q Quarterly report Jun 30, 2025
Aug 11, 2025 8-K items 2.02, 9.01 Results released · Current report
Jul 30, 2025 SCHEDULE 13G Large holder notice
Jun 16, 2025 SCHEDULE 13G Large holder notice
Jun 13, 2025 8-K item 5.07 Shareholder vote · Current report Jun 12, 2025
Jun 4, 2025 8-K items 7.01, 9.01 Investor disclosure (Regulation FD) · Current report
May 12, 2025 10-Q Quarterly report Mar 31, 2025
May 12, 2025 8-K items 2.02, 9.01 Results released · Current report
Apr 29, 2025 ARS Annual report to shareholders Dec 31, 2024
Apr 29, 2025 DEFA14A Extra proxy material
Apr 29, 2025 DEF 14A Proxy statement Jun 12, 2025
Mar 20, 2025 10-K Annual report Dec 31, 2024
Mar 20, 2025 8-K items 2.02, 9.01 Results released · Current report
Feb 18, 2025 SCHEDULE 13D Activist holder notice
40 of 65 shown

Every row opens the filing on EDGAR. The plain words are the site's own for each form and each 8-K item; the complete history, insider forms included, is on EDGAR.

SI Assistanton SION · research, not advice