---
schema_version: "secwatch.filing_event.v1"
accession: "0001213900-25-093936"
form_type: "8-K"
ticker: "OSTX"
cik: "0001795091"
company_name: "OS Therapies Inc"
filed_at: "2025-09-30T23:59:59+00:00"
generated_at: "2026-05-17T05:17:18.803859+00:00"
event_type: "other_material"
sentiment: "neutral"
materiality_score: 0.5
calibrated_materiality_score: 0.5
confidence: "high"
source: SEC EDGAR
---

# OS Therapies files prospectus supplement for resale of up to 4.37M shares by selling stockholders

## Summary
- Prospectus supplement covers resale of up to 4,373,043 shares of common stock by selling stockholders.
- Shares are being registered for resale under existing S-3 shelf (File No. 333-289443) declared effective August 12, 2025.
- Company is not issuing new shares or raising capital from this resale registration.
- Legal opinion on share legality from Olshan Frome Wolosky LLP filed as Exhibit 5.1.
- Filing date: September 30, 2025; no change in business operations or financial guidance.

## SEC filing metadata
- accession: 0001213900-25-093936
- form_type: 8-K
- ticker: OSTX
- cik: 0001795091
- company_name: OS Therapies Inc
- filed_at: 2025-09-30T23:59:59+00:00
- event_type: other_material
- sentiment: neutral
- materiality_score: 0.5
- calibrated_materiality_score: 0.5
- confidence: high
- sec_items: 8.01, 9.01
- EDGAR index: https://www.sec.gov/Archives/edgar/data/1795091/000121390025093936/0001213900-25-093936-index.htm
- EDGAR primary document: https://www.sec.gov/Archives/edgar/data/1795091/000121390025093936/ea0259321-8k_ostherap.htm

## Machine-readable alternates
- HTML: https://secwatch.observer/filing/0001213900-25-093936
- JSON: https://secwatch.observer/filing/0001213900-25-093936.json
- Plain text: https://secwatch.observer/filing/0001213900-25-093936.txt

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