BENDER JEREMY (Chief Executive Officer) sold 7.0% of their position (15.46K shares) of DAY ONE BIOPHARMACEUTICALS, INC. on the open market

Open‑market sale worth $179.3K — a moderate reduction. Review remaining holdings and any 10b5‑1 plan disclosures.

S · 1 sale

BENDER JEREMY

Filed: 2/18/2026ACC: 0001863107-26-000004

InsiderBENDER JEREMYCIK 1863107

→

IssuerDAY ONE BIOPHARMACEUTICALS, INC.CIK 1845337

DirectorOfficer· Chief Executive Officer

Since May 2021

-15.46K

Net shares

Net seller

$179.3K

Total sold

Open market trades

0B · 1S

Total transactions

42.94K acquired · 58.40K disposed

Non-Derivative Transactions5

Common Stock

Direct

M · Option Exercise

+4.75K

Price / share

—

Trade value

—

% of position

2.7%

2/15/2026

177.16K→181.91K

Common Stock

Direct

M · Option Exercise

+11.69K

Price / share

—

Trade value

—

% of position

6.4%

2/15/2026

181.91K→193.60K

Common Stock

Direct

M · Option Exercise

+11.69K

Price / share

—

Trade value

—

% of position

6.0%

2/15/2026

193.60K→205.29K

Common Stock

Direct

M · Option Exercise

+14.81K

Price / share

—

Trade value

—

% of position

7.2%

2/15/2026

205.29K→220.10K

Common Stock

Direct

S · Sale

−15.46K

Price / share

$11.60

Trade value

$179.34K

% of position

7.0%

2/17/2026

220.06K→204.60K

Total

Net shares

+27.48K

Net value

-$179.34K

Security	Date	Type	Shares	Price / Share	Trade Value	% of Position	Held Before	Held After
Common Stock Direct	2/15/2026	M · Option Exercise	+4.75K	—	—	2.7%	177.16K	181.91K
Common Stock Direct	2/15/2026	M · Option Exercise	+11.69K	—	—	6.4%	181.91K	193.60K
Common Stock Direct	2/15/2026	M · Option Exercise	+11.69K	—	—	6.0%	193.60K	205.29K
Common Stock Direct	2/15/2026	M · Option Exercise	+14.81K	—	—	7.2%	205.29K	220.10K
Common Stock Direct	2/17/2026	S · Sale	−15.46K	$11.60	$179.34K	7.0%	220.06K	204.60K
Total			+27.48K		-$179.34K

Derivative Transactions4

Restricted Stock Unit (RSU)

Direct

M · Option Exercise

Converts to

Common Stock

4.75K shares

−4.75K

Strike price

Held after

14.25K

Exercisable

—

2/15/2026

Restricted Stock Unit (RSU)

Direct

M · Option Exercise

Converts to

Common Stock

11.69K shares

−11.69K

Strike price

Held after

81.82K

Exercisable

—

2/15/2026

Restricted Stock Unit (RSU)

Direct

M · Option Exercise

Converts to

Common Stock

11.69K shares

−11.69K

Strike price

Held after

128.56K

Exercisable

—

2/15/2026

Restricted Stock Unit (RSU)

Direct

M · Option Exercise

Converts to

Common Stock

14.81K shares

−14.81K

Strike price

Held after

222.19K

Exercisable

—

2/15/2026

Security	Converts To	Date	Type	Shares	Exercisable	Held After
Restricted Stock Unit (RSU) Direct	Common Stock4.75K shares	2/15/2026	M · Option Exercise	−4.75K	—	14.25K
Restricted Stock Unit (RSU) Direct	Common Stock11.69K shares	2/15/2026	M · Option Exercise	−11.69K	—	81.82K
Restricted Stock Unit (RSU) Direct	Common Stock11.69K shares	2/15/2026	M · Option Exercise	−11.69K	—	128.56K
Restricted Stock Unit (RSU) Direct	Common Stock14.81K shares	2/15/2026	M · Option Exercise	−14.81K	—	222.19K

Non-Derivative Holdings (Post-Transaction)6

Common Stock

Indirect

Shares owned300K

Common Stock

Indirect

Shares owned18.20K

Common Stock

Indirect

Shares owned300K

Common Stock

Indirect

Shares owned808.28K

Common Stock

Indirect

Shares owned147.70K

Common Stock

Indirect

Shares owned20.20K

Total

1.59M indirect1.59M

Security Title	Shares Owned	Ownership Type
Common Stock	300K	Indirect
Common Stock	18.20K	Indirect
Common Stock	300K	Indirect
Common Stock	808.28K	Indirect
Common Stock	147.70K	Indirect
Common Stock	20.20K	Indirect
Total	1.59M	1.59M indirect

Derivative Holdings (Post-Transaction)0

No derivative holdings reported