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Day One Biopharmaceuticals, Inc.

DAWNDelisted Apr 23, 2026
Industry
Pharmaceutical Preparations
SEC CIK
0001845337

Day One Biopharmaceuticals, Inc. was delisted on Apr 23, 2026; its insiders filed their last Form 4 on Apr 27, 2026; 208 institutions reported holding it in 13F filings for Q1 2026, worth $1.85B in total; Soros Fund Management was the only superinvestor holding it.

Open-market trades, last 90 days

Open-market purchases (P) and sales (S) by Day One Biopharmaceuticals, Inc. insiders, counted by Form 4 filing. Trades with a flagged price and duplicate filings are left out.

Open-market buys
0 filings
Open-market sells
0 filings
Insiders trading
0
Net value
$0
Purchases minus sales

Insider roster

Directors, officers and 10% owners who have filed a Form 4 for Day One Biopharmaceuticals, Inc., current and former, most recent filer first. Last reported holding is the position after the last non-derivative trade in their latest filing.

Insider roster for Day One Biopharmaceuticals, Inc.
NameTitleLast reported holdingLast filingFilings, past year
Blavatnik Len10% Owner0Apr 27, 20261
Access Industries Holdings LLC10% Owner0Apr 27, 20261
Access Industries Management, LLC10% Owner0Apr 27, 20261
AI Day1 LLC10% Owner0Apr 27, 20261
Garland J. ScottDirector–Apr 23, 20262
Ramasastry SairaDirector0Apr 23, 20262
Holles Natalie C.Director0Apr 23, 20262
Nicholson Garry ADirector–Apr 23, 20262
York Charles N IICOO and CFO0Apr 23, 20265
Dable Habib JDirector–Apr 23, 20262
Grossman WilliamDirector–Apr 23, 20262
Vasconcelles MichaelHead of Research and Dev.0Apr 23, 20263
Dubow AdamGen Counsel & Secretary0Apr 23, 20265
Josey John A.Director0Apr 23, 20262
Merendino LaurenChief Commercial Officer0Apr 23, 20265
Bender JeremyCHIEF EXECUTIVE OFFICER0IndirectApr 23, 20266
Blackman Samuel C.HEAD OF R&D1,034,015Dec 12, 20240
Gladstone MichaelDirector766,667IndirectMay 28, 20240
Becker Daniel J.Director–Jun 26, 20230
Grant Papanek JulieDirector330,000IndirectMar 3, 20230
Atlas Venture Fund XI, L.P.10% Owner6,008,534Dec 14, 20220
Canaan XI L.P.10% Owner6,964,301Sep 22, 20220
Canaan Partners XI LLC10% Owner6,964,301Sep 22, 20220
Atlas Venture Opportunity Fund I, L.P.10% Owner793,116Jul 6, 20220
Atlas Venture Associates Opportunity I, L.P.10% Owner766,667Jun 22, 20220
Atlas Venture Associates Opportunity I, LLC10% Owner766,667Jun 22, 20220
Atlas Venture Associates XI, LLC10% Owner766,667Jun 22, 20220
Atlas Venture Associates XI, L.P.10% Owner766,667Jun 22, 20220
Atlas Venture Opportunity Fund II, L.P.10% Owner766,667Jun 22, 20220
Millennium Pharmaceuticals Inc10% Owner6,120,124IndirectDec 9, 20210
Takeda Pharmaceutical Co Ltd10% Owner6,120,124IndirectDec 9, 20210
Takeda Pharmaceuticals U.S.A., Inc.10% Owner6,120,124IndirectDec 9, 20210
Takeda Ventures, Inc.10% Owner6,120,124IndirectDec 9, 20210

Insider trades

Each row adds up one type of transaction in one Form 4 filing. Only open-market purchases (P) and sales (S) are shown by default; use the filters to see grants, option exercises and other codes.

Insider trades
Filed (ET)Trade dateFiling delayInsiderTransactionSharesAvg priceValueHolding changeFlags
Dec 3, 2021 (view filing)Dec 12 daysBlackman Samuel C.Chief Medical OfficerSSale−10.0K$17.22−$172.2K−0.7%1.38M after3 lots
Dec 7, 2021 (view filing)6:01 AM ETDec 3-64 daysMillennium Pharmaceuticals Inc and 3 others10% OwnerSSale−110.2K$18.10−$1.99M−1.7%6.42M after2 lots
Dec 9, 2021 (view filing)6:04 AM ETDec 7-82 daysMillennium Pharmaceuticals Inc and 3 others10% OwnerSSale−297.3K$18.49−$5.50M−4.6%6.12M after3 lots
Jan 5, 2022 (view filing)Jan 32 daysBlackman Samuel C.Chief Medical OfficerSSale−10.0K$17.10−$171.0K−0.7%1.37M after2 lots
Jan 20, 2022 (view filing)6:37 PM ETJan 18-202 daysBlavatnik Len and 3 othersOther: Affiliate of 10% OwnerPPurchase+106.9K$14.52+$1.55M+1.1%9.48M after3 lots
Jun 17, 2022 (view filing)Jun 152 daysBlackman Samuel C.Chief Medical OfficerSSale−50.0K$16.26−$813.0K−3.7%1.32M after
Jun 21, 2022 (view filing)4:37 PM ETJun 174 daysBlavatnik Len and 3 othersOther: Affiliate of 10% OwnerPPurchase+1.20M$15.00+$18.0M+12.7%10.7M after
Jun 22, 2022 (view filing)Jun 175 daysGladstone MichaelDirectorPPurchase+766.7K$15.00+$11.5MNew position766.7K after
Jun 22, 2022 (view filing)5:09 PM ETJun 175 daysAtlas Venture Fund XI, L.P. and 6 others10% OwnerPPurchase+766.7K$15.00+$11.5MNew position766.7K afterDuplicate filing
Jul 6, 2022 (view filing)Jul 1-55 daysBender JeremyChief Executive OfficerSSale−2.60K$20.00−$52.1K−0.2%1.26M after2 lots
Jul 6, 2022 (view filing)Jul 15 daysBlackman Samuel C.Chief Medical OfficerSSale−10.0K$18.72−$187.2K−0.8%1.31M after3 lots
Jul 6, 2022 (view filing)Jul 1-55 daysYork Charles N IICOO, CFO and SecretarySSale−2.28K$20.00−$45.6K−0.7%335.3K after2 lots
Jul 12, 2022 (view filing)Jul 84 daysBender JeremyChief Executive OfficerSSale−1.79K$20.00−$35.9K−0.1%1.26M after
Jul 12, 2022 (view filing)Jul 84 daysYork Charles N IICOO, CFO and SecretarySSale−1.42K$20.00−$28.3K−0.4%333.9K after
Jul 12, 2022 (view filing)Jul 84 daysGrant Papanek JulieDirectorSSale−1.24K$20.00−$24.8K−0.3%462.0K after
Jul 12, 2022 (view filing)Jul 1-511 daysGrant Papanek JulieDirectorSSale−1.80K$20.00−$36.0K−0.4%463.2K afterAmended2 lots
Jul 20, 2022 (view filing)Jul 182 daysBender JeremyChief Executive OfficerSSale−2.60K$20.00−$52.0K−0.2%1.26M after
Jul 20, 2022 (view filing)Jul 182 daysGrant Papanek JulieDirectorSSale−2.60K$20.00−$52.0K−0.6%459.4K after
Jul 20, 2022 (view filing)Jul 182 daysYork Charles N IICOO, CFO and SecretarySSale−2.50K$20.00−$50.0K−0.7%331.4K after
Aug 3, 2022 (view filing)Aug 12 daysBlackman Samuel C.Chief Medical OfficerSSale−10.0K$16.88−$168.8K−0.8%1.30M after
Aug 5, 2022 (view filing)Aug 41 dayBender JeremyChief Executive OfficerSSale−12.5K$20.00−$250.0K−1.0%1.25M after
Aug 5, 2022 (view filing)Aug 41 dayYork Charles N IICOO, CFO and SecretarySSale−10.0K$20.05−$200.5K−3.0%321.4K after
Aug 8, 2022 (view filing)Aug 4-54 daysGrant Papanek JulieDirectorSSale−10.0K$20.00−$200.0K−2.2%449.4K after2 lots
Aug 17, 2022 (view filing)Aug 161 dayYork Charles N IICOO, CFO and SecretarySSale−1.09K$24.31−$26.5K−0.3%324.4K after
Aug 17, 2022 (view filing)Aug 161 dayBender JeremyChief Executive OfficerSSale−4.00K$24.31−$97.3K−0.3%1.25M after
Aug 17, 2022 (view filing)Aug 161 dayBlackman Samuel C.Chief Medical OfficerSSale−941$24.31−$22.9K−0.1%1.30M after
Sep 6, 2022 (view filing)Sep 15 daysBender JeremyChief Executive OfficerSSale−12.5K$23.25−$290.6K−1.0%1.24M after2 lots
Sep 6, 2022 (view filing)Sep 15 daysBender JeremyChief Executive OfficerSSale−12.5K$23.25−$290.6K−1.0%1.24M after2 lotsDuplicate filing
Sep 6, 2022 (view filing)Sep 15 daysBlackman Samuel C.Chief Medical OfficerSSale−10.0K$23.24−$232.4K−0.8%1.29M after2 lots
Sep 6, 2022 (view filing)Sep 15 daysGrant Papanek JulieDirectorSSale−5.00K$23.27−$116.4K−1.1%444.4K after2 lots
Sep 6, 2022 (view filing)Sep 15 daysYork Charles N IICOO, CFO and SecretarySSale−10.0K$23.25−$232.5K−3.1%314.4K after2 lots
Sep 15, 2022 (view filing)Sep 13-152 daysGrant Papanek JulieDirectorSSale−245.0K$23.76−$5.82M−2.5%9.42M after6 lots
Sep 15, 2022 (view filing)Sep 213 daysLateGrant Papanek JulieDirectorSSale−5.00K$23.82−$119.1K−1.1%439.4K after
Sep 15, 2022 (view filing)7:48 PM ETSep 13-152 daysCanaan XI L.P. and 1 other10% OwnerSSale−245.0K$23.76−$5.82M−2.5%9.42M after6 lotsDuplicate filing
Sep 20, 2022 (view filing)Sep 16-204 daysGrant Papanek JulieDirectorSSale−340.7K$20.44−$6.96M−3.6%9.08M after5 lots
Sep 20, 2022 (view filing)5:47 PM ETSep 16-204 daysCanaan XI L.P. and 1 other10% OwnerSSale−340.7K$20.44−$6.96M−3.6%9.08M after5 lotsDuplicate filing
Sep 22, 2022 (view filing)Sep 211 dayGrant Papanek JulieDirectorSSale−613.6K$18.55−$11.4M−6.8%8.46M after2 lots
Sep 22, 2022 (view filing)4:00 PM ETSep 211 dayCanaan XI L.P. and 1 other10% OwnerSSale−613.6K$18.55−$11.4M−6.8%8.46M after2 lotsDuplicate filing
Oct 5, 2022 (view filing)Oct 32 daysBender JeremyChief Executive OfficerSSale−12.5K$20.05−$250.6K−1.0%1.23M after
Oct 5, 2022 (view filing)Oct 32 daysBlackman Samuel C.Chief Medical OfficerSSale−10.0K$19.99−$199.9K−0.8%1.28M after
Oct 5, 2022 (view filing)Oct 3-42 daysGrant Papanek JulieDirectorSSale−10.0K$20.03−$200.3K−2.3%429.4K after2 lots
Oct 5, 2022 (view filing)Oct 32 daysYork Charles N IICOO, CFO and SecretarySSale−10.0K$20.05−$200.5K−3.2%304.4K after
Nov 3, 2022 (view filing)Nov 12 daysBender JeremyChief Executive OfficerSSale−12.5K$20.03−$250.4K−1.0%1.22M after
Nov 3, 2022 (view filing)Nov 12 daysBlackman Samuel C.Chief Medical OfficerSSale−10.0K$20.01−$200.1K−0.8%1.27M after
Nov 3, 2022 (view filing)Nov 1-22 daysGrant Papanek JulieDirectorSSale−10.0K$20.03−$200.3K−2.3%419.4K after2 lots
Nov 3, 2022 (view filing)Nov 12 daysYork Charles N IICOO, CFO and SecretarySSale−10.0K$20.03−$200.3K−3.3%294.4K after
Nov 17, 2022 (view filing)Nov 161 dayBender JeremyChief Executive OfficerSSale−1.51K$21.46−$32.5K−0.1%1.22M after
Nov 17, 2022 (view filing)Nov 161 dayBlackman Samuel C.Chief Medical OfficerSSale−377$21.46−$8.09K0.0%1.27M after
Nov 17, 2022 (view filing)Nov 161 dayYork Charles N IICOO, CFO and SecretarySSale−430$21.46−$9.23K−0.1%296.5K after
Nov 22, 2022 (view filing)Nov 211 dayBender JeremyChief Executive OfficerSSale−12.5K$20.76−$259.5K−1.0%1.20M after2 lots