---
schema_version: "secwatch.filing_event.v1"
accession: "0001193125-25-306786"
form_type: "8-K"
ticker: "STRO"
cik: "0001382101"
company_name: "SUTRO BIOPHARMA, INC."
filed_at: "2025-12-03T23:59:59+00:00"
generated_at: "2026-05-16T15:05:39.539246+00:00"
event_type: "other_material"
sentiment: "negative"
materiality_score: 0.75
calibrated_materiality_score: 0.75
confidence: "high"
source: SEC EDGAR
---

# Sutro Biopharma announces 1-for-10 reverse stock split effective Dec 3 to regain Nasdaq compliance

## Summary
- Reverse stock split at 1-for-10, effective 12:01 a.m. ET on December 3, 2025.
- Outstanding shares reduced from ~85.2M to ~8.52M; symbol STRO unchanged, new CUSIP 869367201.
- Intended to regain Nasdaq minimum bid price compliance; approved by stockholders on June 6, 2025.
- No fractional shares issued; any fractional interest rounded up to nearest whole share.
- Proportionate adjustments to equity awards, exercise prices, and shares reserved under equity plans.

## SEC filing metadata
- accession: 0001193125-25-306786
- form_type: 8-K
- ticker: STRO
- cik: 0001382101
- company_name: SUTRO BIOPHARMA, INC.
- filed_at: 2025-12-03T23:59:59+00:00
- event_type: other_material
- sentiment: negative
- materiality_score: 0.75
- calibrated_materiality_score: 0.75
- confidence: high
- sec_items: 3.03, 5.03, 8.01, 9.01
- EDGAR index: https://www.sec.gov/Archives/edgar/data/1382101/000119312525306786/0001193125-25-306786-index.htm
- EDGAR primary document: https://www.sec.gov/Archives/edgar/data/1382101/000119312525306786/stro-20251201.htm

## Machine-readable alternates
- HTML: https://secwatch.observer/filing/0001193125-25-306786
- JSON: https://secwatch.observer/filing/0001193125-25-306786.json
- Plain text: https://secwatch.observer/filing/0001193125-25-306786.txt

## Key facts
- Governance Changes
  SUTRO BIOPHARMA, INC.: Amendment to Restated Certificate of Incorporation to effect a 1-for-10 reverse stock split (effective 2025-12-03).
  - Change: charter amendment
  - Effective: 2025-12-03
  source text: On December 2, 2025, Sutro Biopharma, Inc. (the “ Company ”) filed a Certificate of Amendment (the “ Amendment ”) to its Restated Certificate of Incorporation (the “ Certificate of Incorporation ”) with the Secretary of State of the State of Delaware to implement a 1-for-10 reverse stock split (the “ Reverse Stock Split ”) of the Company’s common stock, par value $0.001 per share (the “ Common Stock ”) to be effective as of 12:01 am Eastern time on December 3, 2025 (the “ Effective Time ”).
  evidence_url: https://www.sec.gov/Archives/edgar/data/1382101/000119312525306786/0001193125-25-306786-index.htm

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