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

SecurityDAWN / Day One Biopharmaceuticals, Inc.
InstitutionBarclays Plc
Latest Disclosed Ownership292,325 shares
Latest Disclosed Value $ 2,724,467
Barclays Plc ownership in DAWN / Day One Biopharmaceuticals, Inc.

On February 13, 2026 - Barclays Plc filed a 13F-HR form disclosing ownership of 292,325 shares of Day One Biopharmaceuticals, Inc. (US:DAWN) valued at $2,724,469 USD as of December 31, 2025. The entity filed a previous 13F-HR/A on March 31, 2026 disclosing 347,185 shares of Day One Biopharmaceuticals, Inc.. This represents a change in shares of -15.80% during the quarter. The current value of the position is $6,293,757 USD.

Barclays Plc 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 30,800 of underlying shares valued at $287,056 USD and put options representing 35,000 of underlying shares valued at $326,200 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)
2026-02-13 2025-12-31 13F DAY ONE BIOPHARMACEUTICALS I COM 23954D109 292,325 -54,860 -15.80 2,724 11.32 0.0007
2026-03-31 2025-09-30 13F/A-3 DAY ONE BIOPHARMACEUTICALS I COM 23954D109 347,185 -924 -0.27 2,448 8.18 0.0005
2026-03-19 2025-09-30 13F/A-2 DAY ONE BIOPHARMACEUTICALS I COM 23954D109 135,373 -212,736 1,886 0.0005
2025-11-12 2025-09-30 13F DAY ONE BIOPHARMACEUTICALS I COM 23954D109 347,185 -924 2,448 0.0005
2026-02-27 2025-06-30 13F/A-2 DAY ONE BIOPHARMACEUTICALS I COM 23954D109 348,109 192,900 124.28 2,263 83.90 0.0005
2025-08-14 2025-06-30 13F/A-1 DAY ONE BIOPHARMACEUTICALS I COM 23954D109 348,109 192,900 2 0.0005
2025-08-13 2025-06-30 13F DAY ONE BIOPHARMACEUTICALS I COM 23954D109 348,109 192,900 2 0.0002
2026-03-17 2025-03-31 13F/A-1 DAY ONE BIOPHARMACEUTICALS I COM 23954D109 155,209 13,757 9.73 1,231 -31.36 0.0003
2025-05-15 2025-03-31 13F DAY ONE BIOPHARMACEUTICALS I COM 23954D109 155,209 13,757 1 0.0003
2026-03-19 2024-12-31 13F/A-1 DAY ONE BIOPHARMACEUTICALS I COM 23954D109 141,452 6,079 4.49 1,792 -4.93 0.0005
2025-02-13 2024-12-31 13F DAY ONE BIOPHARMACEUTICALS I COM 23954D109 141,452 6,079 2 0.0005
2026-03-31 2024-09-30 13F/A-2 DAY ONE BIOPHARMACEUTICALS I COM 23954D109 135,373 79,779 143.50 1,886 146.08 0.0005
2024-11-19 2024-09-30 13F/A-1 DAY ONE BIOPHARMACEUTICALS I COM 23954D109 135,373 79,779 2 0.0005
2024-11-15 2024-09-30 13F DAY ONE BIOPHARMACEUTICALS I COM 23954D109 135,373 79,779 2 0.0002
2026-03-23 2024-06-30 13F/A-1 DAY ONE BIOPHARMACEUTICALS I COM 23954D109 55,594 -11,872 -17.60 766 -31.24 0.0002
2024-08-14 2024-06-30 13F DAY ONE BIOPHARMACEUTICALS I COM 23954D109 55,594 -11,872 1 0.0002
2026-03-24 2024-03-31 13F/A-1 DAY ONE BIOPHARMACEUTICALS I COM 23954D109 67,466 -118,373 -63.70 1,115 -58.94 0.0004
2024-05-15 2024-03-31 13F DAY ONE BIOPHARMACEUTICALS I COM 23954D109 67,466 -118,373 1 0.0004
2026-03-25 2023-12-31 13F/A-1 DAY ONE BIOPHARMACEUTICALS I COM 23954D109 185,839 53,957 40.91 2,713 67.68 0.0010
2024-02-15 2023-12-31 13F DAY ONE BIOPHARMACEUTICALS I COM 23954D109 185,839 53,957 3 0.0010
2026-03-26 2023-09-30 13F/A-1 DAY ONE BIOPHARMACEUTICALS I COM 23954D109 131,882 -12,521 -8.67 1,618 -6.15 0.0010
2023-11-07 2023-09-30 13F DAY ONE BIOPHARMACEUTICALS I COM 23954D109 131,882 -12,521 2 0.0010
2026-03-30 2023-06-30 13F/A-2 DAY ONE BIOPHARMACEUTICALS I COM 23954D109 144,403 70,834 96.28 1,724 75.38 0.0011
2023-09-20 2023-06-30 13F/A-1 DAY ONE BIOPHARMACEUTICALS I COM 23954D109 144,403 70,834 2 0.0011
2023-08-03 2023-06-30 13F DAY ONE BIOPHARMACEUTICALS I COM 23954D109 144,403 70,834 2 0.0011
2026-03-30 2023-03-31 13F/A-1 DAY ONE BIOPHARMACEUTICALS I COM 23954D109 73,569 -35,983 -32.85 984 -58.29 0.0005
2023-05-04 2023-03-31 13F DAY ONE BIOPHARMACEUTICALS I COM 23954D109 73,569 -35,983 1 0.0005
2026-03-30 2022-12-31 13F/A-1 DAY ONE BIOPHARMACEUTICALS I COM 23954D109 109,552 19,123 21.15 2,358 30.08 0.0011
2023-02-13 2022-12-31 13F DAY ONE BIOPHARMACEUTICALS I COM 23954D109 109,552 19,123 2 0.0011
2022-11-03 2022-09-30 13F DAY ONE BIOPHARMACEUTICALS I COM 23954D109 90,429 89,257 7,615.78 1,812 8,528.57 0.0020
2022-08-12 2022-06-30 13F DAY ONE BIOPHARMACEUTICALS I COM 23954D109 1,172 -4,315 -78.64 21 -61.82 0.0000
2022-05-16 2022-03-31 13F DAY ONE BIOPHARMACEUTICALS I COM 23954D109 5,487 5,487 55 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
(%)
2026-02-13 2025-12-31 13F DAY ONE BIOPHARMACEUTICALS I OPT Call 30,800 2.67 287 -31.18 n/a n/a n/a
2026-03-19 2025-09-30 13F/A DAY ONE BIOPHARMACEUTICALS I OPT Call 30,000 418 n/a n/a n/a
2025-08-14 2025-06-30 13F/A DAY ONE BIOPHARMACEUTICALS I OPT Call 0 0 n/a n/a n/a
2026-02-27 2025-06-30 13F/A DAY ONE BIOPHARMACEUTICALS I OPT Call 0 -100.00 0 -100.00 n/a n/a n/a
2025-08-13 2025-06-30 13F DAY ONE BIOPHARMACEUTICALS I OPT Call 0 0 n/a n/a n/a
2026-03-17 2025-03-31 13F/A DAY ONE BIOPHARMACEUTICALS I OPT Call 9,000 0.00 71 -37.72 n/a n/a n/a
2025-05-15 2025-03-31 13F DAY ONE BIOPHARMACEUTICALS I OPT Call 9,000 0 n/a n/a n/a
2026-03-19 2024-12-31 13F/A DAY ONE BIOPHARMACEUTICALS I OPT Call 9,000 -70.00 114 -72.66 n/a n/a n/a
2025-02-13 2024-12-31 13F DAY ONE BIOPHARMACEUTICALS I OPT Call 9,000 0 n/a n/a n/a
2024-11-19 2024-09-30 13F/A DAY ONE BIOPHARMACEUTICALS I OPT Call 30,000 0 n/a n/a n/a
2026-03-31 2024-09-30 13F/A DAY ONE BIOPHARMACEUTICALS I OPT Call 30,000 418 n/a n/a n/a
2024-11-15 2024-09-30 13F DAY ONE BIOPHARMACEUTICALS I OPT Call 30,000 0 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
(%)
2026-02-13 2025-12-31 13F DAY ONE BIOPHARMACEUTICALS I OPT Put 35,000 16.67 326 -21.82 n/a n/a n/a
2026-03-19 2025-09-30 13F/A DAY ONE BIOPHARMACEUTICALS I OPT Put 30,000 418 n/a n/a n/a
2025-08-14 2025-06-30 13F/A DAY ONE BIOPHARMACEUTICALS I OPT Put 0 0 n/a n/a n/a
2026-02-27 2025-06-30 13F/A DAY ONE BIOPHARMACEUTICALS I OPT Put 0 -100.00 0 -100.00 n/a n/a n/a
2025-08-13 2025-06-30 13F DAY ONE BIOPHARMACEUTICALS I OPT Put 0 0 n/a n/a n/a
2026-03-17 2025-03-31 13F/A DAY ONE BIOPHARMACEUTICALS I OPT Put 9,000 0.00 71 -37.72 n/a n/a n/a
2025-05-15 2025-03-31 13F DAY ONE BIOPHARMACEUTICALS I OPT Put 9,000 0 n/a n/a n/a
2026-03-19 2024-12-31 13F/A DAY ONE BIOPHARMACEUTICALS I OPT Put 9,000 -70.00 114 -72.66 n/a n/a n/a
2025-02-13 2024-12-31 13F DAY ONE BIOPHARMACEUTICALS I OPT Put 9,000 0 n/a n/a n/a
2024-11-19 2024-09-30 13F/A DAY ONE BIOPHARMACEUTICALS I OPT Put 30,000 0 n/a n/a n/a
2026-03-31 2024-09-30 13F/A DAY ONE BIOPHARMACEUTICALS I OPT Put 30,000 418 n/a n/a n/a
2024-11-15 2024-09-30 13F DAY ONE BIOPHARMACEUTICALS I OPT Put 30,000 0 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.