---
schema_version: "secwatch.filing_event.v1"
accession: "0001728117-26-000079"
form_type: "8-K"
ticker: "GOSS"
cik: "0001728117"
company_name: "Gossamer Bio, Inc."
filed_at: "2026-08-26T20:01:53+00:00"
generated_at: "2026-08-26T20:03:56.208766+00:00"
event_type: "other_material"
sentiment: "neutral"
materiality_score: 0.4
calibrated_materiality_score: 0.4
confidence: "medium"
source: SEC EDGAR
---

# Gossamer Bio closes private placement, files Series A-1 preferred stock designation

## Summary
- On Aug 24, 2026, Gossamer Bio filed a Certificate of Designation for Series A-1 Convertible Preferred Stock with Delaware.
- Filing made in connection with closing of previously announced private placement; terms incorporated by reference from Aug 21, 2026 8-K.
- Certificate of Designation filed as Exhibit 3.1; no new financial details disclosed in this filing.
- Company amended its amended and restated certificate of incorporation to effect the designation.

## SEC filing metadata
- accession: 0001728117-26-000079
- form_type: 8-K
- ticker: GOSS
- cik: 0001728117
- company_name: Gossamer Bio, Inc.
- filed_at: 2026-08-26T20:01:53+00:00
- event_type: other_material
- sentiment: neutral
- materiality_score: 0.4
- calibrated_materiality_score: 0.4
- confidence: medium
- sec_items: 5.03, 1.01, 9.01
- EDGAR index: https://www.sec.gov/Archives/edgar/data/1728117/000172811726000079/0001728117-26-000079-index.htm
- EDGAR primary document: https://www.sec.gov/Archives/edgar/data/1728117/000172811726000079/goss-20260824.htm

## Machine-readable alternates
- HTML: https://secwatch.observer/filing/0001728117-26-000079
- JSON: https://secwatch.observer/filing/0001728117-26-000079.json
- Plain text: https://secwatch.observer/filing/0001728117-26-000079.txt

This AI-assisted summary is a reading aid. Review the linked SEC EDGAR filing before relying on any specific claim.