Day One Biopharma (DAWN) insider sells shares to cover RSU taxes

Rhea-AI Filing Summary

Day One Biopharmaceuticals general counsel and secretary Adam Dubow reported an open-market sale of 6,395 shares of common stock at a weighted-average price of $11.6009, undertaken solely to cover his tax liability from the settlement of restricted stock units.

On February 15, several restricted stock unit (RSU) awards were settled into common stock at no cash cost, with each RSU delivering one share upon vesting. After these transactions, Dubow directly held 72,694 shares of common stock. The RSUs vest over time in quarterly installments, subject to his continued service.

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

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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^*

Dubow Adam

(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)

	Director		10% Owner
X	Officer (give title below)		Other (specify below)
	Gen Counsel & Secretary

3. Date of Earliest Transaction (Month/Day/Year)
02/15/2026

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
Common Stock	02/15/2026		M		2,963	A	(1)	65,589	D
Common Stock	02/15/2026		M		1,750	A	(1)	67,339	D
Common Stock	02/15/2026		M		3,688	A	(1)	71,027	D
Common Stock	02/15/2026		M		3,687	A	(1)	74,714	D
Common Stock	02/15/2026		M		4,375	A	(1)	79,089	D
Common Stock	02/17/2026		S(2)		6,395	D	$11.6009(3)	72,694	D

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
Restricted Stock Unit (RSU)	(1)	02/15/2026		M			2,963	(4)	(5)	Common Stock	2,963	$0	8,889	D
Restricted Stock Unit (RSU)	(1)	02/15/2026		M			1,750	(6)	(5)	Common Stock	1,750	$0	5,250	D
Restricted Stock Unit (RSU)	(1)	02/15/2026		M			3,688	(6)	(5)	Common Stock	3,688	$0	25,816	D
Restricted Stock Unit (RSU)	(1)	02/15/2026		M			3,687	(6)	(5)	Common Stock	3,687	$0	40,565	D
Restricted Stock Unit (RSU)	(1)	02/15/2026		M			4,375	(6)	(5)	Common Stock	4,375	$0	65,625	D

Explanation of Responses:

1. Each Restricted Stock Unit ("RSU") represents a contingent right to receive one share of the Issuer's Common Stock upon settlement for no consideration.

2. The sale of shares is for the sole purpose of covering the Reporting Person's tax liability with respect to the settlement of RSUs.

3. The price reported in Column 4 is a weighted average price. These shares were sold as part of block trades for multiple security holders of the Issuer at prices ranging from $11.195 to $11.8508, inclusive. The Reporting Person undertakes to provide to the Issuer, any securityholder of the Issuer or the staff of the Securities and Exchange Commission, upon request, full information regarding the number of shares sold at each separate price within the range set forth herein with regard to the block trade.

4. The RSUs vest as to 25% of the total award on November 15, 2023, and 1/12th of the remaining amount vest in quarterly installments thereafter on February 15, May 15, August 15 and November 15, subject to the Reporting Person's provision of service to the Issuer on each vesting date.

5. RSUs do not expire; they either vest or are canceled prior to the vesting date.

6. The RSUs will vest as to 1/16th of the total award in quarterly installments on February 15, May 15, August 15 and November 15, 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	02/18/2026
	** 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).
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FAQ

What insider transactions did Adam Dubow report in Day One Biopharmaceuticals (DAWN) Form 4?

Adam Dubow reported selling 6,395 shares of Day One Biopharmaceuticals common stock in an open-market transaction and settling multiple restricted stock unit (RSU) awards into common shares, all as part of routine equity compensation and related tax obligations.

Why did Adam Dubow sell 6,395 DAWN shares according to the latest Form 4?

The Form 4 states that the 6,395-share sale was executed solely to cover Adam Dubow’s tax liability arising from the settlement of his restricted stock units. This indicates the transaction was tax-related rather than a discretionary reduction of his overall equity exposure.

At what price were Adam Dubow’s DAWN shares sold in the reported transaction?

The reported sale of 6,395 Day One Biopharmaceuticals shares occurred at a weighted-average price of $11.6009. Footnotes explain the shares were sold in block trades for multiple holders at prices ranging from $11.195 to $11.8508 per share.

How do Adam Dubow’s restricted stock units (RSUs) in DAWN vest over time?

One RSU award vests 25% on November 15, 2023, with the remaining amount vesting in equal quarterly installments on February 15, May 15, August 15, and November 15. Another RSU grant vests 1/16th quarterly on the same schedule, contingent on continued service.

What does each DAWN restricted stock unit (RSU) provide to Adam Dubow upon settlement?

Each restricted stock unit gives Adam Dubow a contingent right to receive one share of Day One Biopharmaceuticals common stock upon settlement for no cash consideration, meaning he does not pay a strike price when RSUs convert into shares as they vest.

How many DAWN common shares did Adam Dubow hold after the reported transactions?

Following the reported sale and RSU settlements, Adam Dubow’s direct ownership stood at 72,694 shares of Day One Biopharmaceuticals common stock, reflecting his remaining equity position after covering tax obligations tied to vested restricted stock units.