---
schema_version: "secwatch.filing_event.v1"
accession: "0001171843-23-003757"
form_type: "8-K"
ticker: "APTOF"
cik: "0000882361"
company_name: "Aptose Biosciences Inc."
filed_at: "2023-06-05T23:59:59+00:00"
generated_at: "2026-06-14T07:44:56.927159+00:00"
event_type: "other"
sentiment: "neutral"
materiality_score: 0.5
calibrated_materiality_score: 0.5
confidence: "high"
source: SEC EDGAR
---

# Aptose Biosciences effects 1-for-15 reverse stock split, trading starts June 6

## Summary
- Shareholders approved ratio range 1-for-10 to 1-for-20 at May 23, 2023 meeting; board set final ratio at 1-for-15.
- Articles of amendment filed under CBCA on May 24, 2023; split-adjusted trading begins on Nasdaq and TSX on June 6, 2023.
- Post-split shares outstanding approximately 6.3 million; no fractional shares issued, rounded down.
- Common shares continue trading under symbols APTO (Nasdaq) and APS (TSX); new CUSIP 03835T309 and ISIN CA03835T3091.
- Proportionate adjustments made to exercise prices and shares underlying outstanding equity awards and plans.

## SEC filing metadata
- accession: 0001171843-23-003757
- form_type: 8-K
- ticker: APTOF
- cik: 0000882361
- company_name: Aptose Biosciences Inc.
- filed_at: 2023-06-05T23:59:59+00:00
- event_type: other
- sentiment: neutral
- materiality_score: 0.5
- calibrated_materiality_score: 0.5
- confidence: high
- sec_items: 3.03, 5.03, 8.01, 9.01
- EDGAR index: https://www.sec.gov/Archives/edgar/data/882361/000117184323003757/0001171843-23-003757-index.htm
- EDGAR primary document: https://www.sec.gov/Archives/edgar/data/882361/000117184323003757/f8k_060223.htm

## Machine-readable alternates
- HTML: https://secwatch.observer/filing/0001171843-23-003757
- JSON: https://secwatch.observer/filing/0001171843-23-003757.json
- Plain text: https://secwatch.observer/filing/0001171843-23-003757.txt

## Key facts
- Governance Changes
  Aptose Biosciences Inc.: Filed articles of amendment to implement a 1-for-15 reverse stock split (effective 2023-06-06).
  - Change: charter amendment
  - Effective: 2023-06-06
  source text: The following day, the Company filed articles of amendment under the Canadian Business Corporations Act to implement the Reverse Stock Split.
  evidence_url: https://www.sec.gov/Archives/edgar/data/882361/000117184323003757/0001171843-23-003757-index.htm

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