Day One Biopharmaceuticals, Inc.
US ˙ NasdaqGS ˙ US23954D1090
DETTE SYMBOL ER IKKE LÆNGERE AKTIVT

SecurityDAWN / Day One Biopharmaceuticals, Inc.
InstitutionCitadel Advisors Llc
ManagerKen Griffin
Latest Disclosed Ownership0 shares
Latest Disclosed Value $ 0
Citadel Advisors Llc ownership in DAWN / Day One Biopharmaceuticals, Inc.

On May 15, 2026 - Citadel Advisors Llc filed a 13F-HR form disclosing ownership of 0 shares of Day One Biopharmaceuticals, Inc. (US:DAWN) valued at $0 USD as of March 31, 2026. The entity filed a previous 13F-HR on February 17, 2026 disclosing 1,359,613 shares of Day One Biopharmaceuticals, Inc.. This represents a change in shares of -100.00% during the quarter. The current value of the position is $0 USD.

Citadel Advisors Llc has a history of taking positions in derivatives of the underlying security (DAWN) in the form of stock options. The firm currently holds call options representing 261,700 of underlying shares valued at $5,610,848 USD and put options representing 157,000 of underlying shares valued at $3,366,080 USD .

Note: prior versions of this page mistakenly stated that the share values represented the number of options, not the number of underlying shares. For more information on the data backing these reports, please see the SEC document Frequently Asked Questions About Form 13F.

Institutional Ownership: 13F and NPORT Filings

The Security and Class in the table below are shown exactly as filed by the investor. We do our best to track continuity of investments through acquisitions, and this will be reflected in the table as changes in names. In addition to descriptive data, performance of the investment is shown over time. To calculate quarterly performance, we first calculate cost basis of the shares purchased during the quarter, then use that to calculate gross profit. Quarterly return is Gross Profit / Starting Portfolio value.

Note that cost basis is calculated and stored in thousands, so small quarterly changes in shares frequently result in a cost basis of zero.

Upgrade to unlock premium data and export to Excel .

Institutional Put/Call Ratios
(Premium Subscription Required)

In addition to reporting standard equity and debt issues, institutions with more than 100MM assets under management must also disclose their put and call option holdings. Since put options generally indicate negative sentiment, and call options indicate positive sentiment, we can get a sense of the overall institutional sentiment by plotting the ratio of puts to calls. The chart to the right plots the historical put/call ratio for this instrument.

Using Put/Call Ratio as an indicator of investor sentiment overcomes one of the key deficiencies of using total institutional ownership, which is that a significant amount of assets under management are invested passively to track indices. Passively-managed funds do not typically buy options, so the put/call ratio indicator more closely tracks the sentiment of actively-managed funds.

DAWN / Day One Biopharmaceuticals, Inc. Historical Put/Call Ratio
Disclosed Equity Positions (from 13F/NPORT Filings)
File
Date
Effective
Date
Form Security Class ID Avg Price
Paid (Est)
Reported
Shares
ΔShares ΔShares
(%)
Reported
Value
(x1000)
ΔValue
(%)
Alloc
(%)
ΔAlloc ΔAlloc (%) Cost Basis
(x1000)
Unrealized
Gain/Loss
(x1000)
2026-05-15 2026-03-31 13F DAY ONE BIOPHARMACEUTICALS I COM 23954D109 0 -1,359,613 -100.00 0 -100.00
2026-02-17 2025-12-31 13F DAY ONE BIOPHARMACEUTICALS I COM 23954D109 1,359,613 696,400 105.00 12,672 171.04 0.0019
2025-11-14 2025-09-30 13F DAY ONE BIOPHARMACEUTICALS I COM 23954D109 663,213 -40,431 -5.75 4,676 2.23 0.0007
2025-08-14 2025-06-30 13F DAY ONE BIOPHARMACEUTICALS I COM 23954D109 703,644 -635,374 -47.45 4,574 -56.93 0.0008
2025-05-15 2025-03-31 13F DAY ONE BIOPHARMACEUTICALS I COM 23954D109 1,339,018 727,705 119.04 10,618 37.09 0.0020
2025-02-14 2024-12-31 13F DAY ONE BIOPHARMACEUTICALS I COM 23954D109 611,313 127,052 26.24 7,745 14.83 0.0013
2024-11-14 2024-09-30 13F DAY ONE BIOPHARMACEUTICALS I COM 23954D109 484,261 114,653 31.02 6,746 32.44 0.0013
2024-08-14 2024-06-30 13F DAY ONE BIOPHARMACEUTICALS I COM 23954D109 369,608 322,343 681.99 5,093 552.95 0.0010
2024-05-15 2024-03-31 13F DAY ONE BIOPHARMACEUTICALS I COM 23954D109 47,265 39,998 550.41 781 635.85 0.0002
2024-02-14 2023-12-31 13F DAY ONE BIOPHARMACEUTICALS I COM 23954D109 7,267 513 7.60 106 29.27 0.0000
2023-11-14 2023-09-30 13F DAY ONE BIOPHARMACEUTICALS I COM 23954D109 6,754 -765,402 -99.13 83 -99.11 0.0000
2023-08-14 2023-06-30 13F DAY ONE BIOPHARMACEUTICALS I COM 23954D109 772,156 378,072 95.94 9,220 75.00 0.0019
2023-05-15 2023-03-31 13F DAY ONE BIOPHARMACEUTICALS I COM 23954D109 394,084 387,213 5,635.47 5,269 3,483.67 0.0012
2023-02-14 2022-12-31 13F DAY ONE BIOPHARMACEUTICALS I COM 23954D109 6,871 -41,077 -85.67 148 -84.70 0.0000
2022-11-14 2022-09-30 13F DAY ONE BIOPHARMACEUTICALS I COM 23954D109 47,948 -11,856 -19.82 961 -10.19 0.0002
2022-08-15 2022-06-30 13F DAY ONE BIOPHARMACEUTICALS I COM 23954D109 59,804 -51,932 -46.48 1,070 -3.43 0.0003
2022-05-16 2022-03-31 13F DAY ONE BIOPHARMACEUTICALS I COM 23954D109 111,736 111,736 1,108 0.0002
Disclosed Call Options
File
Date
Effective
Date
Form Security Class ID Opt Avg Share
Price
Shares ΔShares
(%)
Value
(x1000)
ΔValue
(%)
Prior Allocation
(%)
Allocation
(%)
ΔAllocation
(%)
Cost Basis
(x1000)
Profit
(x1000)
Return
(%)
2026-05-15 2026-03-31 13F DAY ONE BIOPHARMACEUTICALS I COM Call 261,700 39.28 5,611 220.39 n/a n/a n/a
2026-02-17 2025-12-31 13F DAY ONE BIOPHARMACEUTICALS I COM Call 187,900 1,751 n/a n/a n/a
2025-11-14 2025-09-30 13F DAY ONE BIOPHARMACEUTICALS I COM Call 0 -100.00 0 -100.00 n/a n/a n/a
2025-08-14 2025-06-30 13F DAY ONE BIOPHARMACEUTICALS I COM Call 19,600 66.10 127 36.56 n/a n/a n/a
2025-05-15 2025-03-31 13F DAY ONE BIOPHARMACEUTICALS I COM Call 11,800 -35.87 94 -60.09 n/a n/a n/a
2025-02-14 2024-12-31 13F DAY ONE BIOPHARMACEUTICALS I COM Call 18,400 91.67 233 75.19 n/a n/a n/a
2024-11-14 2024-09-30 13F DAY ONE BIOPHARMACEUTICALS I COM Call 9,600 -63.22 134 -62.95 n/a n/a n/a
2024-08-14 2024-06-30 13F DAY ONE BIOPHARMACEUTICALS I COM Call 26,100 70.59 360 42.46 n/a n/a n/a
2024-05-15 2024-03-31 13F DAY ONE BIOPHARMACEUTICALS I COM Call 15,300 -16.39 253 -5.62 n/a n/a n/a
2024-02-14 2023-12-31 13F DAY ONE BIOPHARMACEUTICALS I COM Call 18,300 8.28 267 28.99 n/a n/a n/a
2023-11-14 2023-09-30 13F DAY ONE BIOPHARMACEUTICALS I COM Call 16,900 -53.06 207 -51.75 n/a n/a n/a
2023-08-14 2023-06-30 13F DAY ONE BIOPHARMACEUTICALS I COM Call 36,000 -31.30 430 -38.71 n/a n/a n/a
2023-05-15 2023-03-31 13F DAY ONE BIOPHARMACEUTICALS I COM Call 52,400 96.99 701 22.38 n/a n/a n/a
2023-02-14 2022-12-31 13F DAY ONE BIOPHARMACEUTICALS I COM Call 26,600 572 n/a n/a n/a
2022-11-14 2022-09-30 13F DAY ONE BIOPHARMACEUTICALS I COM Call 0 -100.00 0 -100.00 n/a n/a n/a
2022-08-15 2022-06-30 13F DAY ONE BIOPHARMACEUTICALS I COM Call 57,600 1,031 n/a n/a n/a
Disclosed Put Options
File
Date
Effective
Date
Form Security Class ID Opt Avg Share Price Shares ΔShares
(%)
Value
(x1000)
ΔValue
(%)
Prior Allocation
(%)
Allocation
(%)
ΔAllocation
(%)
Cost Basis
(x1000)
Profit
(x1000)
Return
(%)
2026-05-15 2026-03-31 13F DAY ONE BIOPHARMACEUTICALS I COM Put 157,000 0.00 3,366 130.08 n/a n/a n/a
2026-02-17 2025-12-31 13F DAY ONE BIOPHARMACEUTICALS I COM Put 157,000 1,463 n/a n/a n/a
2025-11-14 2025-09-30 13F DAY ONE BIOPHARMACEUTICALS I COM Put 0 -100.00 0 -100.00 n/a n/a n/a
2025-08-14 2025-06-30 13F DAY ONE BIOPHARMACEUTICALS I COM Put 23,500 -65.94 153 -72.21 n/a n/a n/a
2025-05-15 2025-03-31 13F DAY ONE BIOPHARMACEUTICALS I COM Put 69,000 -15.85 547 -47.30 n/a n/a n/a
2025-02-14 2024-12-31 13F DAY ONE BIOPHARMACEUTICALS I COM Put 82,000 219.07 1,039 189.94 n/a n/a n/a
2024-11-14 2024-09-30 13F DAY ONE BIOPHARMACEUTICALS I COM Put 25,700 -44.37 358 -43.71 n/a n/a n/a
2024-08-14 2024-06-30 13F DAY ONE BIOPHARMACEUTICALS I COM Put 46,200 126.47 637 88.72 n/a n/a n/a
2024-05-15 2024-03-31 13F DAY ONE BIOPHARMACEUTICALS I COM Put 20,400 34.21 337 52.49 n/a n/a n/a
2024-02-14 2023-12-31 13F DAY ONE BIOPHARMACEUTICALS I COM Put 15,200 -1.94 222 16.32 n/a n/a n/a
2023-11-14 2023-09-30 13F DAY ONE BIOPHARMACEUTICALS I COM Put 15,500 17.42 190 21.02 n/a n/a n/a
2023-08-14 2023-06-30 13F DAY ONE BIOPHARMACEUTICALS I COM Put 13,200 -5.04 158 -15.14 n/a n/a n/a
2023-05-15 2023-03-31 13F DAY ONE BIOPHARMACEUTICALS I COM Put 13,900 139.66 186 49.19 n/a n/a n/a
2023-02-14 2022-12-31 13F DAY ONE BIOPHARMACEUTICALS I COM Put 5,800 -58.57 125 -55.71 n/a n/a n/a
2022-11-14 2022-09-30 13F DAY ONE BIOPHARMACEUTICALS I COM Put 14,000 -33.33 280 -25.53 n/a n/a n/a
2022-08-15 2022-06-30 13F DAY ONE BIOPHARMACEUTICALS I COM Put 21,000 376 n/a n/a n/a
Legend
Shares
The total number of shares held by the institution at the end of the reporting period (the effective date). This is provided in the filing.
Value
The total value of the shares as of the effective date. This is provided in the filing.
Avg. Share Price
The weighted average share price of the shares held by the institution. We use FIFO accounting to determine this price
Class
This is the security class as indicated by the filer. There are a variety of values for this field. Common values include "EC" = equity common, "EP" - equity preferred
Allocation (%)
The percent of the institution's portfolio that this position represents. This is provided in NPORT filings. For 13F filings, we calculate it.
Change in Allocation
The change in allocation from the prior reporting period. This is calculated as current allocation - prior allocation.
Change in Allocation (%)
The percent change in allocation from the prior reporting period. This is calculated as (current allocation - prior allocation) / prior allocation.
Cost Basis
The total cost of the shares held. This is calculated as reported shares * avg. share price
Unrealized Gain/Loss
This is the market value of the position as of the effective date minus the cost basis.