---
schema_version: "secwatch.filing_event.v1"
accession: "0001171843-25-004249"
form_type: "8-K"
ticker: "APTOF"
cik: "0000882361"
company_name: "Aptose Biosciences Inc."
filed_at: "2025-07-01T23:59:59+00:00"
generated_at: "2026-05-18T11:33:24.734906+00:00"
event_type: "other_material"
sentiment: "neutral"
materiality_score: 0.3
calibrated_materiality_score: 0.3
confidence: "high"
source: SEC EDGAR
---

# Aptose Biosciences upgraded to OTCQB market; begins trading under APTOF

## Summary
- Company upgraded to OTCQB Market, effective July 1, 2025.
- New ticker symbol APTOF on OTCQB.
- Continues trading on Toronto Stock Exchange under symbol APS.
- OTCQB requires current reporting and annual management certification.

## SEC filing metadata
- accession: 0001171843-25-004249
- form_type: 8-K
- ticker: APTOF
- cik: 0000882361
- company_name: Aptose Biosciences Inc.
- filed_at: 2025-07-01T23:59:59+00:00
- event_type: other_material
- sentiment: neutral
- materiality_score: 0.3
- calibrated_materiality_score: 0.3
- confidence: high
- sec_items: 7.01, 9.01
- EDGAR index: https://www.sec.gov/Archives/edgar/data/882361/000117184325004249/0001171843-25-004249-index.htm
- EDGAR primary document: https://www.sec.gov/Archives/edgar/data/882361/000117184325004249/f8k_070125.htm

## Machine-readable alternates
- HTML: https://secwatch.observer/filing/0001171843-25-004249
- JSON: https://secwatch.observer/filing/0001171843-25-004249.json
- Plain text: https://secwatch.observer/filing/0001171843-25-004249.txt

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