---
schema_version: "secwatch.filing_event.v1"
accession: "0001193125-24-030094"
form_type: "8-K"
ticker: "STRO"
cik: "0001382101"
company_name: "SUTRO BIOPHARMA, INC."
filed_at: "2024-02-09T23:59:59+00:00"
generated_at: "2026-06-06T04:45:38.370640+00:00"
event_type: "other_material"
sentiment: "neutral"
materiality_score: 0.6
calibrated_materiality_score: 0.6
confidence: "high"
source: SEC EDGAR
---

# Sutro Biopharma adds $100M to at-the-market equity program via new shelf registration

## Summary
- Filed prospectus supplement to 2023 Form S-3 shelf, increasing shares available under existing Sales Agreement with Jefferies by $100M.
- Total remaining capacity as of Feb 9, 2024: $29.3M from prior shelf plus $100M new supplement = $129.3M.
- Previously sold $70.7M under the 2021 shelf registration since April 2021.
- Shares sold through Jefferies LLC as sales agent at prevailing market prices.
- Legal opinion on share validity filed as Exhibit 5.1 from Fenwick & West.

## SEC filing metadata
- accession: 0001193125-24-030094
- form_type: 8-K
- ticker: STRO
- cik: 0001382101
- company_name: SUTRO BIOPHARMA, INC.
- filed_at: 2024-02-09T23:59:59+00:00
- event_type: other_material
- sentiment: neutral
- materiality_score: 0.6
- calibrated_materiality_score: 0.6
- confidence: high
- sec_items: 8.01, 9.01
- EDGAR index: https://www.sec.gov/Archives/edgar/data/1382101/000119312524030094/0001193125-24-030094-index.htm
- EDGAR primary document: https://www.sec.gov/Archives/edgar/data/1382101/000119312524030094/d737228d8k.htm

## Machine-readable alternates
- HTML: https://secwatch.observer/filing/0001193125-24-030094
- JSON: https://secwatch.observer/filing/0001193125-24-030094.json
- Plain text: https://secwatch.observer/filing/0001193125-24-030094.txt

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