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Former Aptose Biosciences (APTOF) director exits stake in Hammi acquisition

Filing Impact
(Neutral)
Filing Sentiment
(Neutral)
Form Type
4

Rhea-AI Filing Summary

Former Aptose Biosciences director Warren Whitehead disposed of all his remaining interests in the company on June 30, 2026 as part of a business arrangement under which Hammi Pharmaceuticals acquired all outstanding Aptose shares. He returned 33 common shares at about $1.72 per share and multiple director stock options to the issuer, leaving him with no direct Aptose shares or options after the transactions.

Positive

  • None.

Negative

  • None.
Insider Whitehead Warren
Role null
Type Security Shares Price Value
Disposition Director Stock Option (Right to Buy) 3,333 $0.00 --
Disposition Director Option Grant 100,000 $0.00 --
Disposition Director Option Grant 50,000 $0.00 --
Disposition Director Option Grant 50,000 $0.00 --
Disposition Director Stock Option (Right to Buy) 50,000 $0.00 --
Disposition Director Option Grant 50,000 $0.00 --
Disposition Director Option Grant 152,500 $0.00 --
Disposition Stock Options (Right to Buy) 40,000 $0.00 --
Disposition Director Stock Option (Right to Buy) 53,000 $0.00 --
Disposition Common Shares 33 $1.72 $56.76
Holdings After Transaction: Director Stock Option (Right to Buy) — 0 shares (Direct, null); Director Option Grant — 0 shares (Direct, null); Stock Options (Right to Buy) — 0 shares (Direct, null); Common Shares — 0 shares (Direct, null)
Footnotes (1)
  1. Disposed of pursuant to a board, shareholder and court-approved business arrangement agreement between the Issuer and Hammi Pharmaceuticals Co. Ltd., a South Korean corporation ("Hammi") whereby a subsidiary of Hammi acquired all outstanding shares of the Issuer at a price of C$2.41 per share. Converted from Canadian price of C$2.41 per share using an exchange rate of C$1.4 = US$1.00. Options vest 50% on the first anniversary of grant date; remaining options vest 1/3 annually beginning on the second anniversary of the grant date.
Common shares disposed 33 shares Returned to issuer on June 30, 2026
US dollar share value $1.72 per share Converted from C$2.41 at C$1.4=US$1.00
Canadian consideration price C$2.41 per share Hammi acquisition price for outstanding Aptose shares
Options disposed at $3.52 53,000 options Director stock options with $3.52 exercise price
Options disposed at $1.91 40,000 options Stock options with $1.91 exercise price
Largest option block disposed 152,500 options Director option grant with $6.91 exercise price
Low-strike option block 100,000 options Director option grant with $0.66 exercise price
Post-transaction holdings 0 shares/options Total direct Aptose holdings after reported dispositions
Disposition to issuer financial
"transaction_action: issuer disposition"
business arrangement agreement financial
"Disposed of pursuant to a board, shareholder and court-approved business arrangement agreement"
director stock option financial
"Director Stock Option (Right to Buy)"
option grant financial
"Director Option Grant"
exchange rate financial
"using an exchange rate of C$1.4 = US$1.00"
Exchange rate is the price of one currency expressed in another—for example, how many euros you receive for one US dollar. It matters to investors because changes in that price alter the reported profits, costs and value of assets for companies and portfolios that operate or hold money across borders; think of it like switching measurement units, where the same item can look bigger or smaller depending on the unit used.
Hammi Pharmaceuticals Co. Ltd. financial
"between the Issuer and Hammi Pharmaceuticals Co. Ltd., a South Korean corporation"
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Learn about SEC filing dates
SEC Form 4
FORM 4UNITED STATES SECURITIES AND EXCHANGE COMMISSION
Washington, D.C. 20549

STATEMENT OF CHANGES IN BENEFICIAL OWNERSHIP

Filed pursuant to Section 16(a) of the Securities Exchange Act of 1934
or Section 30(h) of the Investment Company Act of 1940
OMB APPROVAL
OMB Number:3235-0287
Estimated average burden
hours per response:0.5
X
Check this box if no longer subject to Section 16. Form 4 or Form 5 obligations may continue. See Instruction 1(b).
Check this box to indicate that a transaction was made pursuant to a contract, instruction or written plan for the purchase or sale of equity securities of the issuer that is intended to satisfy the affirmative defense conditions of Rule 10b5-1(c). See Instruction 10.
1. Name and Address of Reporting Person*
Whitehead Warren

(Last)(First)(Middle)
C/O APTOSE BIOSCIENCES INC.
251 CONSUMERS ROAD, SUITE 1105

(Street)
TORONTOM2J 4R3

(City)(State)(Zip)

ONTARIO, CANADA

(Country)
2. Issuer Name and Ticker or Trading Symbol
Aptose Biosciences Inc. [ APTO ]
5. Relationship of Reporting Person(s) to Issuer
(Check all applicable)
Director10% Owner
Officer (give title below)XOther (specify below)
FORMER DIRECTOR
2a. Foreign Trading Symbol
3. Date of Earliest Transaction (Month/Day/Year)
06/30/2026
6. Individual or Joint/Group Filing (Check Applicable Line)
XForm filed by One Reporting Person
Form filed by More than One Reporting Person
4. If Amendment, Date of Original Filed (Month/Day/Year)

Table I - Non-Derivative Securities Acquired, Disposed of, or Beneficially Owned
1. Title of Security (Instr. 3) 2. Transaction Date (Month/Day/Year)2A. Deemed Execution Date, if any (Month/Day/Year)3. Transaction Code (Instr. 8) 4. Securities Acquired (A) or Disposed Of (D) (Instr. 3, 4 and 5) 5. Amount of Securities Beneficially Owned Following Reported Transaction(s) (Instr. 3 and 4) 6. Ownership Form: Direct (D) or Indirect (I) (Instr. 4) 7. Nature of Indirect Beneficial Ownership (Instr. 4)
CodeVAmount(A) or (D)Price
Common Shares06/30/2026D(1)33D$1.72(2)0D
Table II - Derivative Securities Acquired, Disposed of, or Beneficially Owned
(e.g., puts, calls, warrants, options, convertible securities)
1. Title of Derivative Security (Instr. 3) 2. Conversion or Exercise Price of Derivative Security 3. Transaction Date (Month/Day/Year)3A. Deemed Execution Date, if any (Month/Day/Year)4. Transaction Code (Instr. 8) 5. Number of Derivative Securities Acquired (A) or Disposed of (D) (Instr. 3, 4 and 5) 6. Date Exercisable and Expiration Date (Month/Day/Year)7. Title and Amount of Securities Underlying Derivative Security (Instr. 3 and 4) 8. Price of Derivative Security (Instr. 5) 9. Number of derivative Securities Beneficially Owned Following Reported Transaction(s) (Instr. 4) 10. Ownership Form: Direct (D) or Indirect (I) (Instr. 4) 11. Nature of Indirect Beneficial Ownership (Instr. 4)
CodeV(A)(D)Date ExercisableExpiration DateTitleAmount or Number of Shares
Director Stock Option (Right to Buy)$1.9706/30/2026D(1)3,333 (3)02/05/2034Common Shares3,333$00D
Director Option Grant$0.6606/30/2026D(1)100,000 (3)01/19/2033Common Shares100,000$00D
Director Option Grant$1.3906/30/2026D(1)50,000 (3)01/17/2032Common Shares50,000$00D
Director Option Grant$1.3906/30/2026D(1)50,000 (3)01/17/2032Common Shares50,000$00D
Director Stock Option (Right to Buy)$4.3806/30/2026D(1)50,000 (3)01/04/2031Common Shares50,000$00D
Director Option Grant$5.1506/30/2026D(1)50,000 (3)03/10/2030Common Shares50,000$00D
Director Option Grant$6.9106/30/2026D(1)152,500 (3)01/30/2030Common Shares152,500$00D
Stock Options (Right to Buy)$1.9106/30/2026D(1)40,000 (3)01/02/2029Common Shares40,000$00D
Director Stock Option (Right to Buy)$3.5206/30/2026D(1)53,000 (3)01/19/2028Common Shares53,000$00D
Explanation of Responses:
1. Disposed of pursuant to a board, shareholder and court-approved business arrangement agreement between the Issuer and Hammi Pharmaceuticals Co. Ltd., a South Korean corporation ("Hammi") whereby a subsidiary of Hammi acquired all outstanding shares of the Issuer at a price of C$2.41 per share.
2. Converted from Canadian price of C$2.41 per share using an exchange rate of C$1.4 = US$1.00.
3. Options vest 50% on the first anniversary of grant date; remaining options vest 1/3 annually beginning on the second anniversary of the grant date.
Remarks:
TOTAL OPTIONS AND OPTION EXERCISE PRICE SUBJECT TO ADJUSTMENT AS A RESULT OF THE ISSUER'S 1:30 REVERSE STOCK SPLIT ON 2/25/25 AND 1:15 REVERSE STOCK SPLIT ON 6/6/2023
/s/ Warren Whitehead07/01/2026
** Signature of Reporting PersonDate
Reminder: Report on a separate line for each class of securities beneficially owned directly or indirectly.
* If the form is filed by more than one reporting person, see Instruction 4 (b)(v).
** Intentional misstatements or omissions of facts constitute Federal Criminal Violations See 18 U.S.C. 1001 and 15 U.S.C. 78ff(a).
Note: File three copies of this Form, one of which must be manually signed. If space is insufficient, see Instruction 6 for procedure.
Persons who respond to the collection of information contained in this form are not required to respond unless the form displays a currently valid OMB Number.
* Form 4: SEC 1474 (03-26)

FAQ

What did Warren Whitehead report in his Aptose Biosciences (APTOF) Form 4?

Warren Whitehead reported disposing of all his remaining Aptose Biosciences holdings. He returned 33 common shares and multiple director stock options to the issuer, leaving him with zero direct Aptose shares or options following the transactions.

Why did Warren Whitehead dispose of his Aptose Biosciences (APTOF) shares and options?

The dispositions occurred under a board, shareholder and court-approved business arrangement. In this deal, a Hammi Pharmaceuticals subsidiary acquired all outstanding Aptose shares, triggering the return of Whitehead’s common shares and options to the issuer.

At what price were Aptose Biosciences (APTOF) shares valued in Warren Whitehead’s Form 4?

The transaction reflects a share price of C$2.41, converted to about $1.72 per share using an exchange rate of C$1.4 to US$1. This value applied to the outstanding Aptose shares acquired by Hammi Pharmaceuticals.

How many Aptose Biosciences (APTOF) common shares did Warren Whitehead dispose of?

He disposed of 33 Aptose common shares. These shares were returned to the issuer as part of the Hammi Pharmaceuticals acquisition transaction, and his reported direct holdings of Aptose common stock fell to zero afterward.

What happened to Warren Whitehead’s Aptose Biosciences (APTOF) stock options?

Whitehead reported the disposition of several blocks of director stock options back to the issuer, covering tens of thousands of underlying common shares at exercise prices ranging from $0.66 to $6.91, leaving no remaining reported options after the transaction.

Does Warren Whitehead still hold any Aptose Biosciences (APTOF) securities after these transactions?

No. The Form 4 shows total shares following each transaction as zero for both common shares and the reported stock options, indicating he no longer holds direct Aptose Biosciences equity or related option positions.