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

SecurityDAWN / Day One Biopharmaceuticals, Inc.
InstitutionCitigroup Inc
Latest Disclosed Ownership13,848 shares
Latest Disclosed Value $ 296,901
Citigroup Inc ownership in DAWN / Day One Biopharmaceuticals, Inc.

On May 11, 2026 - Citigroup Inc filed a 13F-HR form disclosing ownership of 13,848 shares of Day One Biopharmaceuticals, Inc. (US:DAWN) valued at $296,901 USD as of March 31, 2026. The entity filed a previous 13F-HR on February 13, 2026 disclosing 24,094 shares of Day One Biopharmaceuticals, Inc.. This represents a change in shares of -42.53% during the quarter. The current value of the position is $298,147 USD.

Citigroup Inc 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 115,000 of underlying shares valued at $2,465,600 USD and put options representing 115,000 of underlying shares valued at $2,465,600 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.

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Institutional Put/Call Ratios
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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)
2026-05-11 2026-03-31 13F DAY ONE BIOPHARMACEUTICALS I COM 23954D109 13,848 -10,246 -42.53 297 32.14 0.0001
2026-02-13 2025-12-31 13F DAY ONE BIOPHARMACEUTICALS I COM 23954D109 24,094 16,121 202.19 225 300.00 0.0001
2025-11-10 2025-09-30 13F DAY ONE BIOPHARMACEUTICALS I COM 23954D109 7,973 -100,398 -92.64 56 -92.05 0.0000
2025-08-11 2025-06-30 13F DAY ONE BIOPHARMACEUTICALS I COM 23954D109 108,371 -56,305 -34.19 704 -46.05 0.0003
2025-05-12 2025-03-31 13F DAY ONE BIOPHARMACEUTICALS I COM 23954D109 164,676 8,442 5.40 1,306 -34.06 0.0007
2025-02-12 2024-12-31 13F DAY ONE BIOPHARMACEUTICALS I COM 23954D109 156,234 108,164 225.01 1,979 195.81 0.0012
2024-11-12 2024-09-30 13F DAY ONE BIOPHARMACEUTICALS I COM 23954D109 48,070 14,065 41.36 670 42.95 0.0004
2024-08-12 2024-06-30 13F DAY ONE BIOPHARMACEUTICALS I COM 23954D109 34,005 -137,045 -80.12 469 -83.43 0.0003
2024-05-10 2024-03-31 13F DAY ONE BIOPHARMACEUTICALS I COM 23954D109 171,050 71,125 71.18 2,826 93.76 0.0019
2024-02-09 2023-12-31 13F DAY ONE BIOPHARMACEUTICALS I COM 23954D109 99,925 -740 -0.74 1,459 18.06 0.0010
2023-12-06 2023-09-30 13F/A-1 DAY ONE BIOPHARMACEUTICALS I COM 23954D109 100,665 4,234 4.39 1,235 7.30 0.0009
2023-11-09 2023-09-30 13F DAY ONE BIOPHARMACEUTICALS I COM 23954D109 100,665 4,234 1,235 0.0004
2023-08-10 2023-06-30 13F DAY ONE BIOPHARMACEUTICALS I COM 23954D109 96,431 -56,567 -36.97 1,151 -43.72 0.0008
2023-05-11 2023-03-31 13F DAY ONE BIOPHARMACEUTICALS I COM 23954D109 152,998 62,985 69.97 2,046 5.58 0.0014
2023-02-09 2022-12-31 13F DAY ONE BIOPHARMACEUTICALS I COM 23954D109 90,013 -41,733 -31.68 1,937 -26.60 0.0015
2022-11-10 2022-09-30 13F DAY ONE BIOPHARMACEUTICALS I COM 23954D109 131,746 128,981 4,664.77 2,639 5,285.71 0.0019
2022-08-10 2022-06-30 13F DAY ONE BIOPHARMACEUTICALS I COM 23954D109 2,765 562 25.51 49 122.73 0.0000
2022-05-12 2022-03-31 13F DAY ONE BIOPHARMACEUTICALS I COM 23954D109 2,203 -2,479 -52.95 22 -72.15 0.0000
2022-02-10 2021-12-31 13F DAY ONE BIOPHARMACEUTICALS I COM 23954D109 4,682 3,403 266.07 79 163.33 0.0000
2021-11-10 2021-09-30 13F DAY ONE BIOPHARMACEUTICALS I COM 23954D109 1,279 1,279 30 0.0000
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
(%)
2026-05-11 2026-03-31 13F DAY ONE BIOPHARMACEUTICALS I COM Call 115,000 15.00 2,466 164.48 n/a n/a n/a
2026-02-13 2025-12-31 13F DAY ONE BIOPHARMACEUTICALS I COM Call 100,000 932 n/a n/a n/a
2025-11-10 2025-09-30 13F DAY ONE BIOPHARMACEUTICALS I COM Call 0 -100.00 0 -100.00 n/a n/a n/a
2025-08-11 2025-06-30 13F DAY ONE BIOPHARMACEUTICALS I COM Call 62,000 0.00 403 -17.92 n/a n/a n/a
2025-05-12 2025-03-31 13F DAY ONE BIOPHARMACEUTICALS I COM Call 62,000 -28.65 492 -55.40 n/a n/a n/a
2025-02-12 2024-12-31 13F DAY ONE BIOPHARMACEUTICALS I COM Call 86,900 45.08 1,101 32.01 n/a n/a n/a
2024-11-12 2024-09-30 13F DAY ONE BIOPHARMACEUTICALS I COM Call 59,900 99.67 834 101.94 n/a n/a n/a
2024-08-12 2024-06-30 13F DAY ONE BIOPHARMACEUTICALS I COM Call 30,000 413 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
(%)
2026-05-11 2026-03-31 13F DAY ONE BIOPHARMACEUTICALS I COM Put 115,000 15.00 2,466 164.48 n/a n/a n/a
2026-02-13 2025-12-31 13F DAY ONE BIOPHARMACEUTICALS I COM Put 100,000 932 n/a n/a n/a
2025-11-10 2025-09-30 13F DAY ONE BIOPHARMACEUTICALS I COM Put 0 -100.00 0 -100.00 n/a n/a n/a
2025-08-11 2025-06-30 13F DAY ONE BIOPHARMACEUTICALS I COM Put 62,000 0.00 403 -17.92 n/a n/a n/a
2025-05-12 2025-03-31 13F DAY ONE BIOPHARMACEUTICALS I COM Put 62,000 -28.65 492 -55.40 n/a n/a n/a
2025-02-12 2024-12-31 13F DAY ONE BIOPHARMACEUTICALS I COM Put 86,900 45.08 1,101 32.01 n/a n/a n/a
2024-11-12 2024-09-30 13F DAY ONE BIOPHARMACEUTICALS I COM Put 59,900 99.67 834 101.94 n/a n/a n/a
2024-08-12 2024-06-30 13F DAY ONE BIOPHARMACEUTICALS I COM Put 30,000 413 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.