Is Arsenal Biosciences laying off workers?
Yes. Arsenal Biosciences filed a WARN notice in the last 12 months covering 58 jobs. The most recent was filed Aug 31, 2026 for South San Francisco, California, effective Oct 29, 2026. Across every year on record since 2025: 2 notices covering 158 jobs.
158 roles affected across 2 filings.
Filing history
Arsenal Biosciences has filed 2 WARN notices between 2025 and 2026, cutting 158 jobs in total. Down 42% year-on-year: 58 jobs cut in the last 12 months vs 100 the year before.
Every filing
Questions
Yes. Arsenal Biosciences filed a WARN notice in the last 12 months covering 58 jobs. The most recent was filed Aug 31, 2026 for South San Francisco, California, effective Oct 29, 2026. Across every year on record since 2025: 2 notices covering 158 jobs.
58 jobs in WARN notices filed in the last 12 months. 158 jobs across all 2 official WARN filings on record since 2025.
The most recent filing lists an effective date of Oct 29, 2026. The WARN Act requires roughly 60 days' advance notice, so the filing date precedes the job losses.
We'll email you if there are further filings, expansions, or new locations affected.