John A. Josey - 06 Nov 2025 Form 4 Insider Report for Day One Biopharmaceuticals, Inc. (DAWN)

Role
Director
Signature
/s/ Charles N. York II, as Attorney-in-Fact
Issuer symbol
DAWN
Transactions as of
06 Nov 2025
Net transactions value
$0
Form type
4
Filing time
07 Nov 2025, 18:15:50 UTC
Previous filing
04 Jun 2025
SEC
View on sec.gov

Reporting Owners (1)

Name Relationship Address Signature Signature date CIK
Josey John A. Director 1800 SIERRA POINT PARKWAY, SUITE 200, BRISBANE /s/ Charles N. York II, as Attorney-in-Fact 07 Nov 2025 0001776351

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
transaction DAWN Stock Option (right to buy Common Stock) Disposed to Issuer $0 -63,000 -100% $0.000000 0 06 Nov 2025 Common Stock 63,000 $16.00 Direct F1, F2, F3
transaction DAWN Stock Option (right to buy Common Stock) Award $0 +63,000 $0.000000 63,000 06 Nov 2025 Common Stock 63,000 $8.99 Direct F1, F2, F3
transaction DAWN Stock Option (right to buy Common Stock) Disposed to Issuer $0 -1,181 -100% $0.000000 0 06 Nov 2025 Common Stock 1,181 $16.00 Direct F1, F2, F3
transaction DAWN Stock Option (right to buy Common Stock) Award $0 +1,181 $0.000000 1,181 06 Nov 2025 Common Stock 1,181 $8.99 Direct F1, F2, F3
transaction DAWN Stock Option (right to buy Common Stock) Disposed to Issuer $0 -28,700 -100% $0.000000 0 06 Nov 2025 Common Stock 28,700 $16.29 Direct F1, F2, F3
transaction DAWN Stock Option (right to buy Common Stock) Award $0 +28,700 $0.000000 28,700 06 Nov 2025 Common Stock 28,700 $8.99 Direct F1, F2, F3
transaction DAWN Stock Option (right to buy Common Stock) Disposed to Issuer $0 -37,500 -100% $0.000000 0 06 Nov 2025 Common Stock 37,500 $12.69 Direct F1, F2, F3
transaction DAWN Stock Option (right to buy Common Stock) Award $0 +37,500 $0.000000 37,500 06 Nov 2025 Common Stock 37,500 $8.99 Direct F1, F2, F3
transaction DAWN Stock Option (right to buy Common Stock) Disposed to Issuer $0 -32,335 -100% $0.000000 0 06 Nov 2025 Common Stock 32,335 $13.87 Direct F1, F2, F3
transaction DAWN Stock Option (right to buy Common Stock) Award $0 +32,335 $0.000000 32,335 06 Nov 2025 Common Stock 32,335 $8.99 Direct F1, F2, F3
* An asterisk sign (*) next to the price indicates that the price is likely invalid.

Explanation of Responses:

Id Content
F1 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")).
F2 (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.
F3 The options are fully vested.