Aptose Biosciences Inc.
APTODelisted Jul 21, 2025- Industry
- Biological Products, (No Diagnostic Substances)
- SEC CIK
- 0000882361
Aptose Biosciences Inc. was delisted on Jul 21, 2025; its insiders filed their last Form 4 on Jul 2, 2026; 16 institutions reported holding it in 13F filings for Q1 2025, worth $486.8K in total; no superinvestor held it.
Holders of 5% or more of APTO
Holders whose latest Schedule 13D or 13G filing reports 5% or more of Aptose Biosciences Inc., largest stake first. The change is against the holder's previous filing.
| Holder | Latest form | Stake | Change | First filed | Latest filing | Filing |
|---|---|---|---|---|---|---|
| Hanmi Pharmaceutical Co., Ltd. | 13D/A | 19.90%508.7K shares | – | Mar 20, 20251 filing | Mar 20, 2025 | SEC |
Stakes are as of each holder's latest filing. Holders whose last filing was in the old format (before December 18, 2024) have no stake on record and are not listed, and after an acquisition or delisting holders usually stop filing.
13D and 13G filings
7 Schedule 13D and 13G filings on Aptose Biosciences Inc., newest first, including old-format filings without a stake.
| Filed (ET) | Filer | Form | Stake | Change | Event date | Filing |
|---|---|---|---|---|---|---|
| Aug 14, 202511:18 AM ET | Bleichroeder LPand 2 others | 13G/A | 1.61%41.7K shares | −4.69 ppfrom 6.30%Below 5% | Jun 30, 2025 | SEC |
| May 13, 202512:28 PM ET | Bleichroeder LPand 2 others | 13G/A | 6.30%163.0K shares | −1.20 ppfrom 7.50% | Mar 31, 2025 | SEC |
| Mar 24, 20256:48 PM ET | Bleichroeder LPand 2 others | 13G/A | 7.50%163.0K shares | +1.30 ppfrom 6.20% | Mar 24, 2025 | SEC |
| Mar 21, 20257:14 PM ET | Bleichroeder LPand 2 others | 13G/A | 6.20%3.75M shares | 0.00 ppfrom 6.20% | Mar 19, 2025 | SEC |
| Mar 20, 20258:54 PM ET | Hanmi Pharmaceutical Co., Ltd. | 13D/A | 19.90%508.7K shares | – | Mar 18, 2025 | SEC |
| Feb 14, 20254:57 PM ET | Armistice Capital, LLCand 1 other | 13G/A | 4.99%1.03M shares | –Below 5% | Dec 31, 2024 | SEC |
| Feb 13, 20258:26 PM ET | Bleichroeder LPand 1 other | 13G | 6.20%3.75M shares | New | Dec 31, 2024 | SEC |
Form 144: proposed insider sales
Notices from officers, directors and other affiliates planning to sell Aptose Biosciences Inc. shares.
No Form 144 notices for Aptose Biosciences Inc. are on file.