Sionna Therapeutics, Inc.'s latest layoff filing, on September 14, 2026, states charges of approximately $6.4 million. As of November 6, 2026, it has reported this one exit or restructuring plan to the SEC on Form 8-K under Item 2.05. No WARN notice under its name is on file in the states covered here (Form 8-K, September 14, 2026).
Sionna Therapeutics, Inc. announced layoffs on Sep 14. 12 companies announced layoffs this week.
Companies cutting jobs this week. Before you unlock: the company, the number of employees and what is inside. After: every way we found to reach the company. No individual is named in a layoff.
| Artiva Biotherapeutics, Inc. | announced layoffs | |
| Eos Energy Enterprises, Inc. | announced layoffs | |
| SOUNDHOUND AI, INC. | announced layoffs | |
| Portillo's Inc. | announced layoffs | |
| Acumen Pharmaceuticals, Inc. | announced layoffs of about 52 employees |
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Sionna Therapeutics, Inc. reported 1 exit or restructuring plan on Form 8-K under Item 2.05. Each fact below is the filing's own sentence, quoted and linked. No WARN notice under this company's name is on file in the states covered here.
Did Sionna Therapeutics have layoffs in 2026? What its filings say
Sionna Therapeutics, Inc. (CIK 2036042) reported 1 exit or restructuring plan to the SEC on Form 8-K under Item 2.05. The sentences below are quoted from the filings as written.
Form 8-K filed 2026-09-14
Expected charges
The Company currently estimates it will incur aggregate restructuring and related charges of approximately $6.4 million, consisting of approximately $5.3 million in employee severance and other post-employment benefit costs, $0.7 million of contract close-out costs associated with the SION-719 add-on program, and $0.4 million of stock-based compensation expense.
Timing
The workforce reduction and wind-down of applicable vendor arrangements are expected to be substantially completed by the end of the third quarter of 2026, with related cash payments expected to continue into the fourth quarter of 2026.
Also on the record for Sionna Therapeutics, Inc.
| Date | Record | Figure | Our page | Source |
|---|---|---|---|---|
| September 21, 2026 | Stake report, Schedule 13D/A, by RA Capital Management, L.P. | 14.3% of the class | 5%+ stakes | Source |
| May 15, 2026 | Stake report, Schedule 13G/A, by VIKING GLOBAL INVESTORS LP | 7.1% of the class | 5%+ stakes | Source |
| May 12, 2026 | Stake report, Schedule 13G/A, by Qatar Investment Authority | 4.5% of the class | 5%+ stakes | Source |
| April 20, 2026 | Stake report, Schedule 13D/A, by ORBIMED ADVISORS LLC | 6.6% of the class | 5%+ stakes | Source |
| November 7, 2025 | Stake report, Schedule 13D/A, by RA Capital Management, L.P. | 22.6% of the class | 5%+ stakes | Source |
| October 31, 2025 | Stake report, Schedule 13G/A, by JPMORGAN CHASE & CO. | 4.4% of the class | 5%+ stakes | Source |
| October 20, 2025 | Stake report, Schedule 13D/A, by Atlas Venture Fund XI, L.P. | 5.4% of the class | 5%+ stakes | Source |
| July 30, 2025 | Stake report, Schedule 13G, by JPMORGAN CHASE & CO. | 5% of the class | 5%+ stakes | Source |
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More on Sionna Therapeutics, Inc. and the records around it.
Sionna Therapeutics, Inc. elsewhere on the record
- 5%+ stake filings Nov 2026
- Who owns it
Companies that share a holder
- Atlas Venture Fund XI, L.P. also filed stake reports on 3 other companies: DYNE THERAPEUTICS, INC. (Aug 2026), Korro Bio, Inc. (Aug 2026), Day One Biopharmaceuticals, Inc. (May 2026)
- Qatar Investment Authority also filed stake reports on 11 other companies: Aspen Neuroscience, Inc. (Nov 2026), Global Business Travel Group, Inc. (Sep 2026), Nanobiotix SA (Jul 2026)
- VIKING GLOBAL INVESTORS LP also filed stake reports on 27 other companies: City Therapeutics, Inc. (Oct 2026), MID AMERICA APARTMENT COMMUNITIES INC. (Oct 2026), REGAL REXNORD CORP (Sep 2026)
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Public companies must also report to the SEC, on Form 8-K under Item 2.05, when they commit to an exit or restructuring plan that will cost them material charges, which is how most large layoffs and closures by listed companies are disclosed. Those filings are national, so they cover companies in every state. Each sentence shown from one is quoted exactly and linked to the filing; where a filing does not state a figure, none is shown.
Where this comes from
Employers covered by the federal WARN Act, and by the stricter laws some states add, must give written notice before a mass layoff or a site closure. The state labor department publishes those notices. Every row here is one of them, taken from that state's own published file and linked to it, so each figure can be checked at the source.
A notice states the employer, the location, the number of employees affected, and when the layoff or closure takes effect. It does not state a reason, and neither does this page. Where a company also appears in SEC filings under the same name and in the same state, its recorded fundraising is shown alongside, as a matter of record rather than as an explanation. New Jersey and Pennsylvania list a notice under the month it was posted or received, not the day, so their notices show a month. Tennessee gives the county rather than the city.
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