Aptose Biosciences Inc. (APTO) IPO — S-1 Filing, Stock & Insider Activity

Aptose Biosciences Inc. IPO — Status & S-1 Filing

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Updated Jul 16, 2026 · Last SEC filing 2026-07-02

Aptose Biosciences Inc. (APTO) has filed 8 SEC Form 4 insider transactions in the last 90 days, with the most recent on 2026-07-02. 6 Form 8-K material event filings were reported by APTO in the last 90 days. InsiderAlpha tracks every APTO SEC filing — Form 4, Form 144, and 8-K — in real time, including Rule 10b5-1 plan detection.

About Aptose Biosciences Inc. (APTO)

SEC CIK0000882361

90-Day SEC Filing Activity

Form 4 filings (90d)8
Form 8-K filings (90d)6
Latest Form 4 filing2026-07-02

Recent APTO Insider Transactions (Form 4)

DateInsiderRoleTransactionSharesPriceValueFiling
Seizinger Bernd R.InsiderD — Derivative transaction17.0K$1.72$29KSEC
Bejar RafaelInsiderD — Derivative transaction244$1.72$420SEC
BURGER DENIS RInsiderD — Derivative transaction70$1.72$120SEC
Whitehead WarrenInsiderD — Derivative transaction33$1.72$57SEC
Rice William G.Chair, President & CEOD — Derivative transaction613.3K$1.72$1.05MSEC
PLATZER ERICHInsiderD — Derivative transaction1.1K$1.72$2KSEC
Payne FletcherInsiderD — Derivative transaction222$1.72$382SEC
Payne FletcherInsiderD — Derivative transaction22$1.72$38SEC
Vincent Mark D.InsiderD — Derivative transaction14$1.72$24SEC
Rice William G.Chair, President & CEOP — Open-market purchase100.0K$0.20$20KSEC

All transactions sourced from SEC EDGAR Form 4 filings for Aptose Biosciences Inc. (APTO). Updated in real time as new filings are submitted to the SEC.

Most-Active APTO Insiders — Last 90 Days

InsiderForm 4 filingsTotal transaction value
Rice William G.13$1.05M
PLATZER ERICH11$2K
Vincent Mark D.11$24
BURGER DENIS R11$120
Whitehead Warren10$57

Recent APTO Form 8-K Material Events

Recent Insider Filings

Form 4 Transaction Code Reference

SEC Form 4 transactions are reported with a one-letter code indicating the type of transaction. Common codes you'll see in APTO insider filings:

POpen-market purchase by the insider
SOpen-market sale by the insider
AGrant, award, or other acquisition from the issuer
MExercise or conversion of derivative security (e.g. options)
FPayment of exercise price or tax liability via share withholding
GBona-fide gift of securities
DDisposition to the issuer (e.g. share buyback participation)
JOther acquisition or disposition
XExercise of in-the-money or at-the-money derivative security
CConversion of derivative security
VTransaction voluntarily reported earlier than required

APTO Insider Trading — FAQ

What is the latest insider trade for APTO?
Aptose Biosciences Inc. (APTO) had 8 insider filings in the last 90 days, with the most recent on 2026-07-02. InsiderAlpha tracks every Form 4, 10-K, 10-Q, and 8-K filing in real time.
How many insiders are buying APTO stock?
0 insider purchases of APTO were filed in the last 90 days.
How many insiders are selling APTO stock?
0 insider sales of APTO were filed in the last 90 days.
Where can I see APTO SEC filings (Form 4, 10-K, 10-Q, 8-K)?
InsiderAlpha aggregates every APTO SEC filing — Form 4 insider transactions, 10-K and 10-Q quarterly reports, and 8-K material event disclosures — in one timeline.

Learn More

Open the live APTO dashboard on InsiderAlpha for real-time alerts, charting, and full historical filing search.