[Form 4] Day One Biopharmaceuticals, Inc. Insider Trading Activity

Rhea-AI Filing Summary

Day One Biopharmaceuticals (DAWN)November 6, 2025, following Board approval on October 7, 2025. The affected stock options were reset to a new exercise price of $8.99, the Nasdaq closing price on the effective date, with no change to other terms.

Affected grants include options previously priced at $16.00 (covering 1,463,134 shares), $14.26 (397,000 shares), $23.41 (244,000 shares), and $14.44 (286,000 shares). One grant is fully vested; others vest monthly per their original schedules.

Exercising the repriced options at $8.99 requires the CEO to remain in service through the defined Retention Period, which ends on the earlier of the 12‑month anniversary of the effective date or a Corporate Transaction. The transactions were reported as exempt under Rule 16b‑6(d) and Rule 16b‑3.

11/07/2025 - 06:16 PM

SEC Form 4

FORM 4

UNITED 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

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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^*

Bender Jeremy

(Last) (First) (Middle)

1800 SIERRA POINT PARKWAY, SUITE 200

(Street)

BRISBANE CA 94005

(City) (State) (Zip)

2. Issuer Name and Ticker or Trading Symbol
Day One Biopharmaceuticals, Inc. [ DAWN ]

5. Relationship of Reporting Person(s) to Issuer
(Check all applicable)

X	Director		10% Owner
X	Officer (give title below)		Other (specify below)
	CHIEF EXECUTIVE OFFICER

3. Date of Earliest Transaction (Month/Day/Year)
11/06/2025

4. If Amendment, Date of Original Filed (Month/Day/Year)

6. Individual or Joint/Group Filing (Check Applicable Line)

X	Form filed by One Reporting Person
	Form filed by More than One Reporting Person

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)
			Code	V	Amount	(A) or (D)	Price

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)
				Code	V	(A)	(D)	Date Exercisable	Expiration Date	Title	Amount or Number of Shares
Stock Option (right to buy Common Stock)	$16	11/06/2025		D(1)(2)			1,463,134	(3)	05/25/2031	Common Stock	1,463,134	$0	0	D
Stock Option (right to buy Common Stock)	$8.99	11/06/2025		A(1)(2)		1,463,134		(3)	05/25/2031	Common Stock	1,463,134	$0	1,463,134	D
Stock Option (right to buy Common Stock)	$14.26	11/06/2025		D(1)(2)			397,000	(4)	01/17/2032	Common Stock	397,000	$0	0	D
Stock Option (right to buy Common Stock)	$8.99	11/06/2025		A(1)(2)		397,000		(4)	01/17/2032	Common Stock	397,000	$0	397,000	D
Stock Option (right to buy Common Stock)	$23.41	11/06/2025		D(1)(2)			244,000	(5)	01/16/2033	Common Stock	244,000	$0	0	D
Stock Option (right to buy Common Stock)	$8.99	11/06/2025		A(1)(2)		244,000		(5)	01/16/2033	Common Stock	244,000	$0	244,000	D
Stock Option (right to buy Common Stock)	$14.44	11/06/2025		D(1)(2)			286,000	(6)	01/04/2034	Common Stock	286,000	$0	0	D
Stock Option (right to buy Common Stock)	$8.99	11/06/2025		A(1)(2)		286,000		(6)	01/04/2034	Common Stock	286,000	$0	286,000	D
Stock Option (right to buy Common Stock)	$11.87	11/06/2025		D(1)(2)			286,000	(7)	01/14/2035	Common Stock	286,000	$0	0	D
Stock Option (right to buy Common Stock)	$8.99	11/06/2025		A(1)(2)		286,000		(7)	01/14/2035	Common Stock	286,000	$0	286,000	D

Explanation of Responses:

1. On October 7, 2025, the Issuer's Board of Directors approved an option repricing (the "Repricing") whereby the Reporting Person's options were repriced on November 6, 2025 (the "Effective Date") with a new exercise price of $8.99 (if lower than the original exercise price), the closing price on Nasdaq as of the Effective Date. In order to exercise the repriced options at the new exercise price, the Reporting Person is required to remain in service with the Issuer through the Retention Period; provided that the additional premium payment will not be required if the Reporting Person's service to the Issuer is terminated by reason of death or Disability (as defined in the Company's 2021 Equity Incentive Plan ("the Plan")).

2. (Continued from Footnote 1) The "Retention Period" commenced on the Effective Date and ends upon the earliest of (i) the 12-month anniversary of the Effective Date and (ii) a Corporate Transaction (as defined in the Plan). All of the other terms of the options remain unchanged. Such transactions were exempt pursuant to Rule 16b-6(d) and Rule 16b-3 of the Exchange Act, as applicable.

3. The options are fully vested.

4. The option vests as to 2.0833% of the total shares monthly, with 100% of the total shares vested on January 18, 2026, subject to the Reporting Person's provision of service to the Issuer on each vesting date.

5. The option vests as to 1/48th of the total shares monthly, commencing February 17, 2023, subject to the Reporting Person's provision of service to the Issuer on each vesting date.

6. The option vests as to 1/48th of the total shares monthly, commencing February 5, 2024, subject to the Reporting Person's provision of service to the Issuer on each vesting date.

7. The option vests as to 1/48th of the total shares monthly, commencing February 15, 2025, subject to the Reporting Person's provision of service to the Issuer on each vesting date.

	/s/ Charles N. York II, as Attorney-in-Fact	11/07/2025
	** Signature of Reporting Person	Date
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.

FAQ

What did DAWN disclose in this Form 4?

An option repricing for the CEO effective November 6, 2025, with grants reset to an exercise price of $8.99.

Which option grants were repriced for the DAWN CEO?

Grants originally at $16.00 (1,463,134 shares), $14.26 (397,000), $23.41 (244,000), and $14.44 (286,000) were reset to $8.99.

What is the Retention Period referenced by DAWN?

It began on November 6, 2025 and ends on the earlier of the 12‑month anniversary of that date or a Corporate Transaction.

Were vesting terms changed by the repricing at DAWN?

Other terms remain unchanged. One grant is fully vested; others continue to vest monthly per existing schedules.

Did the DAWN Form 4 report any stock sales?

No stock sales were reported; entries reflect option repricing transactions recorded as exempt under Rule 16b‑6(d) and Rule 16b‑3.

When did DAWN’s Board approve the option repricing?

The Board approved the repricing on October 7, 2025.