Samuel C. Blackman - May 26, 2021 Form 3 Insider Report for Day One Biopharmaceuticals, Inc. (DAWN)

Role: Chief Medical Officer
Signature: /s/ Charles N. York II, as Attorney-in-Fact
Stock symbol: DAWN
Transactions as of: May 26, 2021
Transactions value $: $0
Form type: 3
Date filed: 5/26/2021, 09:00 PM
Next filing: Dec 3, 2021

Transactions Table

Type	Sym	Class	Transaction	Value $	Shares	Change %	* Price $	Shares After	Date	Ownership	Footnotes
holding	DAWN	Common Stock						2.39M	May 26, 2021	Direct	F1

Derivative Securities (e.g., puts, calls, warrants, options, convertible securities)

Type	Sym	Class	Transaction	Value $	Shares	Change %	* Price $	Shares After	Date	Underlying Class	Amount	Exercise Price	Ownership	Footnotes
holding	DAWN	Stock Option (right to buy Common Stock)							May 26, 2021	Common Stock	58.2K	$16.00	Direct	F2
holding	DAWN	Stock Option (right to buy Common Stock)							May 26, 2021	Common Stock	135K	$16.00	Direct	F3

* An asterisk sign (*) next to the price indicates that the price is likely invalid.

Explanation of Responses:

Id	Content
F1	Certain of the shares are subject to the Issuer's right of repurchase if underlying vesting conditions are not met.
F2	The option vests as to 25% of the total shares on October 6, 2021 and then 2.0833% of the total shares vest monthly thereafter, with 100% of the total shares vested on October 6, 2024, subject to the Reporting Person's provision of service to the Issuer on each vesting date.
F3	The option vests as to 25% of the total shares on May 23, 2022 and then 2.0833% of the total shares vest monthly thereafter, with 100% of the total shares vested on May 23, 2025, subject to the Reporting Person's provision of service to the Issuer on each vesting date.