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

Rhea-AI Filing Summary

Jeremy Bender, Chief Executive Officer and director of Day One Biopharmaceuticals, Inc. (DAWN), reported vesting settlements of multiple Restricted Stock Units (RSUs) on 08/15/2025 that converted into common shares and a subsequent sale on 08/18/2025. The Form 4 shows acquisitions by settlement: 3,562, 4,750, 11,687 and 11,687 RSUs converting to common stock. On 08/18/2025 the filing reports a sale of 16,058 shares at a weighted average price of $6.7671, disclosed as executed to cover the reporting person's tax liability from RSU settlement. The filing also discloses significant indirect holdings across several trusts, including 1,408,285 shares held in the Bender Revocable Trust.

Positive

• Executive alignment: Multiple RSUs vested, increasing the CEO's direct stake and aligning interests with shareholders.
• Large indirect holdings: Substantial shares held across family and revocable trusts (including 1,408,285 shares) demonstrate significant insider exposure to company performance.
• Transparent disclosure: Filing states the sale was to cover taxes and provides weighted average price range details for the block trade.

Negative

• Share sale reported: CEO sold 16,058 shares on 08/18/2025 at a weighted average price of $6.7671, which reduces a portion of direct holdings (disclosed as tax-related).

Insights

Insider Trading Analyst

TL;DR: CEO received vested RSUs and sold a slice to cover taxes; overall ownership remains concentrated via trusts.

The reported transactions are routine compensation settlements: multiple RSUs vested and converted into common stock on 08/15/2025. The subsequent block sale of 16,058 shares on 08/18/2025 was disclosed as tax-withholding related and executed at a weighted average price of $6.7671. Material concentration of indirect ownership is evident, notably 1,408,285 shares in the Bender Revocable Trust, indicating continued alignment between management and long-term shareholding. No indications of opportunistic trading beyond tax-related disposition are provided in the filing.

Corporate Governance Expert

TL;DR: Compensation-related vesting and a limited sale for tax purposes; governance implications are standard.

The Form 4 documents standard equity compensation mechanics: time-based RSU vesting (1/16th per quarter) and settlement for no consideration, followed by a narrow sale to satisfy tax obligations. The presence of multiple irrevocable and revocable trusts holding shares reflects common estate and succession planning for an executive. The filing is transparent about the purpose of the sale and provides customary detail about trust holdings, which supports governance transparency.

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^*

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)
08/15/2025

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
Common Stock	08/15/2025		M		3,562	A	(1)	149,299	D
Common Stock	08/15/2025		M		4,750	A	(1)	154,049	D
Common Stock	08/15/2025		M		11,687	A	(1)	165,736	D
Common Stock	08/15/2025		M		11,687	A	(1)	177,423	D
Common Stock	08/18/2025		S(2)		16,058	D	$6.7671(3)	161,365	D
Common Stock								14,450	I	See footnote(4)
Common Stock								20,204	I	See footnote(5)
Common Stock								147,702	I	See footnote(6)
Common Stock								18,197	I	See footnote(7)
Common Stock								1,408,285	I	See footnote(8)

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)	08/15/2025		M			3,562	(9)	(10)	Common Stock	3,562	$0	3,570	D
Restricted Stock Unit (RSU)	(1)	08/15/2025		M			4,750	(9)	(10)	Common Stock	4,750	$0	23,750	D
Restricted Stock Unit (RSU)	(1)	08/15/2025		M			11,687	(9)	(10)	Common Stock	11,687	$0	105,191	D
Restricted Stock Unit (RSU)	(1)	08/15/2025		M			11,687	(9)	(10)	Common Stock	11,687	$0	151,939	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 $6.65 to $6.87, 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. Represents shares held by The Jeremy Bender 2022 Grantor Retained Annuity Trust under Irrevocable Trust Agreement dated March 29, 2022 of which the Reporting Person is trustee.

5. Represents shares held by The Jeremy Bender 2023 Grantor Retained Annuity Trust dated June 27, 2023.

6. Represents shares held by The Melissa Bender 2022 Grantor Retained Annuity Trust under Irrevocable Trust Agreement dated March 29, 2022 of which the Reporting Person's spouse is trustee.

7. Represents shares held by The Melissa Bender 2023 Grantor Retained Annuity Trust, dated June 27, 2023.

8. Represents shares held by the Bender Revocable Trust dated January 18, 2017, as amended, Jeremy Bender and Melissa C. Bender, Trustees.

9. 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.

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

	/s/ Charles N. York II, as Attorney-in-Fact	08/19/2025
	** 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.
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FAQ

What transactions did DAWN CEO Jeremy Bender report on Form 4?

The filing reports settlement of RSUs into common stock on 08/15/2025 (3,562; 4,750; 11,687; 11,687 shares) and a sale of 16,058 shares on 08/18/2025.

Why were shares sold by Jeremy Bender according to the Form 4?

The sale of shares was disclosed as executed solely to cover tax liability arising from the RSU settlements.

At what price were the sold DAWN shares executed?

The sale was a block trade at a reported weighted average price of $6.7671, with individual trade prices in a range of $6.65 to $6.87.

How does Jeremy Bender hold additional DAWN shares indirectly?

The Form 4 lists shares held in several trusts, including The Jeremy Bender 2022 and 2023 GRATs, The Melissa Bender trusts, and the Bender Revocable Trust holding 1,408,285 shares.

What is the RSU vesting schedule disclosed in the filing?

RSUs vest as to 1/16th of the total award in quarterly installments on February 15, May 15, August 15 and November 15, subject to continued service.