Day One Bio grants options, RSUs to R&D head

Day One Biopharmaceuticals granted new equity awards to its Head of Research and Development, Michael Vasconcelles, effective January 30, 2026.

Rhea-AI Filing Summary

Day One Biopharmaceuticals granted new equity awards to its Head of Research and Development, Michael Vasconcelles, effective January 30, 2026. He received a stock option for 171,000 shares of common stock at an exercise price of $11.16, plus 114,000 Restricted Stock Units (RSUs).

The option vests as to 1/48 of the total shares each month starting February 28, 2026, contingent on continued service. Each RSU represents one share of common stock and vests 1/16 of the total award quarterly on February 15, May 15, August 15 and November 15, also subject to continued service. RSUs either vest or are canceled; they do not have an expiration date.

Insider Trade Summary

Grant/Award: 285,000 shares

Grant/Award 2 txns

Insider VASCONCELLES MICHAEL

Role Head of Research and Dev.

Type	Security	Shares	Price	Value
Grant/Award	Stock Option (right to buy Common Stock)	171,000	$0.00	$0.00
Grant/Award	Restricted Stock Units	114,000	$0.00	$0.00

Holdings After Transaction: Stock Option (right to buy Common Stock) — 171,000 contracts (Direct); Restricted Stock Units — 114,000 contracts (Direct)

Footnotes (4)

1. F1. The option vests as to 1/48th of the total shares monthly, commencing February 28, 2026, subject to the Reporting Person's provision of service to the Issuer on each vesting date.
2. F2. Each Restricted Stock Unit ("RSU") represents a contingent right to receive one share of the Issuer's Common Stock upon settlement.
3. F3. The 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 the Reporting Person's provision of service to the Issuer on each vesting date.
4. F4. RSUs do not expire; they either vest or are canceled prior to the vesting date.

FAQ

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What equity awards did Day One Biopharmaceuticals (DAWN) grant to Michael Vasconcelles?

Day One Biopharmaceuticals granted Michael Vasconcelles a stock option and RSUs. He received an option for 171,000 common shares at a $11.16 exercise price and 114,000 Restricted Stock Units, each representing one share of common stock upon settlement, contingent on future service.

How do Michael Vasconcelles’ new stock options at DAWN vest?

The 171,000-share stock option vests in equal monthly installments over four years. Specifically, 1/48 of the total shares vest each month beginning February 28, 2026, provided Michael Vasconcelles continues to provide service to Day One Biopharmaceuticals on each applicable vesting date.

What is the vesting schedule for Michael Vasconcelles’ RSUs at Day One Biopharmaceuticals?

The 114,000 RSUs vest in 16 equal quarterly installments. One-sixteenth of the total award vests on February 15, May 15, August 15 and November 15, with each vesting date requiring continued service to Day One Biopharmaceuticals by Michael Vasconcelles.

What does each RSU granted to Michael Vasconcelles by DAWN represent?

Each Restricted Stock Unit granted to Michael Vasconcelles represents the right to receive one share of Day One Biopharmaceuticals common stock. Delivery occurs upon settlement, assuming the applicable vesting conditions tied to his continued service with the company are satisfied at each vesting date.

Do the RSUs granted to Michael Vasconcelles at Day One Biopharmaceuticals expire?

The RSUs themselves do not have a traditional expiration date. Instead, they either vest according to the specified schedule or are canceled before the relevant vesting date if conditions, such as Michael Vasconcelles’ continued service to Day One Biopharmaceuticals, are not met.

AI-generated analysis. How Rhea-AI works. Not financial advice.

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Accepted by SEC EDGAR 01/30/2026 - 05:18 PM Learn about SEC filing dates

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

OMB Number:			3235-0287
Estimated average burden
hours per response:			0.5

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^*

VASCONCELLES MICHAEL

(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)
	Head of Research and Dev.

3. Date of Earliest Transaction (Month/Day/Year)
01/30/2026

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

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)	$11.16	01/30/2026		A		171,000		(1)	01/29/2036	Common Stock	171,000	$0	171,000	D
Restricted Stock Units	(2)	01/30/2026		A		114,000		(3)	(4)	Common Stock	114,000	$0	114,000	D

Explanation of Responses:

1. The option vests as to 1/48th of the total shares monthly, commencing February 28, 2026, subject to the Reporting Person's provision of service to the Issuer on each vesting date.

2. Each Restricted Stock Unit ("RSU") represents a contingent right to receive one share of the Issuer's Common Stock upon settlement.

3. The 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 the Reporting Person's provision of service to the Issuer on each vesting date.

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

	/s/ Charles N. York II, as Attorney-in-Fact	01/30/2026
	** 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).
** 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.