Gilead Sciences, Inc.
CH ˙ SWX ˙ US3755581036
SecurityCH:GILD / Gilead Sciences, Inc.
InstitutionMarshall Wace, Llp
Latest Disclosed Ownership2,310,515 shares
Latest Disclosed Value $ 322,016,475
Marshall Wace, Llp ownership in GILD / Gilead Sciences, Inc.

On May 14, 2026 - Marshall Wace, Llp filed a 13F-HR form disclosing ownership of 2,310,515 shares of Gilead Sciences, Inc. (CH:GILD) valued at $322,016,475 USD as of March 31, 2026. The entity filed a previous 13F-HR on February 13, 2026 disclosing 793,385 shares of Gilead Sciences, Inc.. This represents a change in shares of 191.22% during the quarter.

Marshall Wace, Llp has a history of taking positions in derivatives of the underlying security (GILD) in the form of stock options. The firm currently holds call options representing 0 of underlying shares valued at $0 USD and put options representing 0 of underlying shares valued at $0 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.

CH:GILD / Gilead Sciences, 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)
2026-05-14 2026-03-31 13F GILEAD SCIENCES COMMON STOCK 375558103 2,310,515 1,517,130 191.22 322,016 230.68 0.1519
2026-02-13 2025-12-31 13F GILEAD SCIENCES COMMON STOCK 375558103 793,385 -1,108,095 -58.28 97,380 -53.86 0.0886
2025-11-13 2025-09-30 13F GILEAD SCIENCES COMMON STOCK 375558103 1,901,480 -49,333 -2.53 211,064 -2.41 0.2141
2025-08-13 2025-06-30 13F GILEAD SCIENCES COMMON STOCK 375558103 1,950,813 1,176,946 152.09 216,287 149.43 0.2436
2025-05-15 2025-03-31 13F GILEAD SCIENCES COMMON STOCK 375558103 773,867 -442,931 -36.40 86,712 -22.85 0.1101
2025-02-13 2024-12-31 13F GILEAD SCIENCES COMMON STOCK 375558103 1,216,798 193,133 18.87 112,396 30.96 0.1351
2024-11-14 2024-09-30 13F GILEAD SCIENCES COMMON STOCK 375558103 1,023,665 903,149 749.40 85,824 938.03 0.1045
2024-08-14 2024-06-30 13F GILEAD SCIENCES COMMON STOCK 375558103 120,516 120,516 8,269 0.0110
2023-11-14 2023-09-30 13F GILEAD SCIENCES COMMON STOCK 375558103 0 -39,190 -100.00 0 -100.00
2023-08-14 2023-06-30 13F GILEAD SCIENCES COMMON STOCK 375558103 39,190 -5,035,412 -99.23 3,020 -99.28 0.0059
2023-05-15 2023-03-31 13F GILEAD SCIENCES COMMON STOCK 375558103 5,074,602 644,672 14.55 421,040 10.71 0.8946
2023-02-14 2022-12-31 13F GILEAD SCIENCES COMMON STOCK 375558103 4,429,930 1,064,987 31.65 380,309 83.21 0.8554
2022-11-14 2022-09-30 13F GILEAD SCIENCES COMMON STOCK 375558103 3,364,943 381,493 12.79 207,583 12.57 0.4549
2022-08-15 2022-06-30 13F GILEAD SCIENCES COMMON STOCK 375558103 2,983,450 493,011 19.80 184,408 24.55 0.3794
2022-05-16 2022-03-31 13F GILEAD SCIENCES COMMON STOCK 375558103 2,490,439 2,462,555 8,831.43 148,057 7,211.46 0.2804
2022-02-14 2021-12-31 13F GILEAD SCIENCES COMMON STOCK 375558103 27,884 18,284 190.46 2,025 201.79 0.0037
2021-11-15 2021-09-30 13F GILEAD SCIENCES COMMON STOCK 375558103 9,600 -114,496 -92.26 671 -92.15 0.0028
2021-08-13 2021-06-30 13F GILEAD SCIENCES COMMON STOCK 375558103 124,096 75,637 156.08 8,547 172.89 0.0416
2021-05-17 2021-03-31 13F GILEAD SCIENCES COMMON STOCK 375558103 48,459 -40,867 -45.75 3,132 -39.82 0.0144
2021-02-16 2020-12-31 13F GILEAD SCIENCES COMMON STOCK 375558103 89,326 89,326 84.33 5,204 66.16 0.0282
2020-08-13 2020-06-30 13F GILEAD SCIENCES COMMON STOCK 375558103 0 -3,799 -100.00 0 -100.00
2020-05-15 2020-03-31 13F GILEAD SCIENCES COMMON STOCK 375558103 3,799 -452,954 -99.17 284 -99.04 0.0028
2020-02-14 2019-12-31 13F GILEAD SCIENCES COMMON STOCK 375558103 456,753 -510,190 -52.76 29,680 -51.57 0.2040
2019-11-14 2019-09-30 13F GILEAD SCIENCES COMMON STOCK 375558103 966,943 307,406 46.61 61,285 37.54 0.4818
2019-08-14 2019-06-30 13F GILEAD SCIENCES COMMON STOCK 375558103 659,537 659,537 -31.79 44,559 -27.29 0.3666
2019-05-14 2019-03-31 13F GILEAD SCIENCES COMMON STOCK 375558103 0 -123,013 -100.00 0 -100.00
2019-02-14 2018-12-31 13F GILEAD SCIENCES COMMON STOCK 375558103 123,013 -134,351 -52.20 7,695 -61.28 0.0785
2018-12-06 2018-09-30 13F/A-1 GILEAD SCIENCES COMMON STOCK 375558103 257,364 241,875 1,561.59 19,871 1,711.39 0.1691
2018-11-14 2018-09-30 13F GILEAD SCIENCES COMMON STOCK 375558103 257,364 241,875 19,871
2018-08-14 2018-06-30 13F GILEAD SCIENCES COMMON STOCK 375558103 15,489 -185,098 -92.28 1,097 -92.75 0.0164
2018-05-15 2018-03-31 13F GILEAD SCIENCES COMMON STOCK 375558103 200,587 200,587 1,195.03 15,122 1,278.49 0.6268
2018-03-29 2017-12-31 13F/A-1 GILEAD SCIENCES COMMON STOCK 375558103 0 -17,562 -100.00 0 -100.00
2017-11-13 2017-09-30 13F GILEAD SCIENCES COMMON STOCK 375558103 17,562 -144,239 -89.15 1,423 -87.61 0.0661
2017-08-04 2017-06-30 13F GILEAD SCIENCES COMMON STOCK 375558103 161,801 161,801 821.31 11,488 707.31 0.5060
2017-05-12 2017-03-31 13F GILEAD SCIENCES COMMON STOCK 375558103 0 -198,367 -100.00 0 -100.00
2017-02-10 2016-12-31 13F GILEAD SCIENCES COMMON STOCK 375558103 198,367 -355,427 -64.18 14,205 -67.58 0.0934
2016-11-10 2016-09-30 13F GILEAD SCIENCES COMMON STOCK 375558103 553,794 -203,420 -26.86 43,817 -30.63 0.3115
2016-08-12 2016-06-30 13F GILEAD SCIENCES COMMON STOCK 375558103 757,214 167,189 28.34 63,167 16.54 0.5311
2016-05-13 2016-03-31 13F GILEAD SCIENCES COMMON STOCK 375558103 590,025 -274,067 -31.72 54,200 -38.01 0.5222
2016-02-10 2015-12-31 13F GILEAD SCIENCES COMMON STOCK 375558103 864,092 -172,835 -16.67 87,438 -14.12 0.8205
2015-11-12 2015-09-30 13F GILEAD SCIENCES COMMON STOCK 375558103 1,036,927 883,381 575.32 101,816 466.37 1.2509
2015-08-14 2015-06-30 13F GILEAD SCIENCES COMMON STOCK 375558103 153,546 99,995 186.73 17,977 242.09 0.2345
2015-05-11 2015-03-31 13F GILEAD SCIENCES COMMON STOCK 375558103 53,551 -233,247 -81.33 5,255 -80.56 0.0685
2015-02-17 2014-12-31 13F GILEAD SCIENCES COMMON STOCK 375558103 286,798 -153,969 -34.93 27,033 -42.38 0.3569
2014-11-13 2014-09-30 13F GILEAD SCIENCES COMMON STOCK 375558103 440,767 327,344 288.60 46,920 398.94 0.6769
2014-08-14 2014-06-30 13F GILEAD SCIENCES COMMON STOCK 375558103 113,423 20,999 22.72 9,404 43.59 0.1384
2014-05-14 2014-03-31 13F GILEAD SCIENCES COMMON STOCK 375558103 92,424 92,424 6,549 0.1191
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
(%)
2026-05-14 2026-03-31 13F GILEAD SCIENCES EQUITY OPTION Call 0 -100.00 0 -100.00 n/a n/a n/a
2026-02-13 2025-12-31 13F GILEAD SCIENCES EQUITY OPTION Call 200 25 n/a n/a n/a
2023-11-14 2023-09-30 13F GILEAD SCIENCES EQUITY OPTION Call 0 -100.00 0 -100.00 n/a n/a n/a
2023-08-14 2023-06-30 13F GILEAD SCIENCES EQUITY OPTION Call 127,200 9,803 n/a n/a n/a
2023-05-15 2023-03-31 13F GILEAD SCIENCES EQUITY OPTION Call 0 -100.00 0 -100.00 n/a n/a n/a
2023-02-14 2022-12-31 13F GILEAD SCIENCES EQUITY OPTION Call 68,300 8.59 5,864 51.15 n/a n/a n/a
2022-11-14 2022-09-30 13F GILEAD SCIENCES EQUITY OPTION Call 62,900 3,879 n/a n/a n/a
2022-05-16 2022-03-31 13F June 22 Calls on GILD US at 72.5, American EQUITY OPTION Call 0 -100.00 0 -100.00 n/a n/a n/a
2022-02-14 2021-12-31 13F June 22 Calls on GILD US at 72.5, American EQUITY OPTION Call 205,000 -31.42 14,885 -28.70 n/a n/a n/a
2021-11-15 2021-09-30 13F October 21 Calls on GILD US at 73, American EQUITY OPTION Call 298,900 1,816.03 20,878 1,843.95 n/a n/a n/a
2021-08-13 2021-06-30 13F July 21 Calls on GILD US at 72.5, American EQUITY OPTION Call 15,600 -61.10 1,074 -58.56 n/a n/a n/a
2021-05-17 2021-03-31 13F April 21 Calls on GILD US at 67.5, American EQUITY OPTION Call 40,100 2,592 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
(%)
2026-05-14 2026-03-31 13F GILEAD SCIENCES EQUITY OPTION Put 0 -100.00 0 -100.00 n/a n/a n/a
2026-02-13 2025-12-31 13F GILEAD SCIENCES EQUITY OPTION Put 100 0.00 12 9.09 n/a n/a n/a
2025-11-13 2025-09-30 13F GILEAD SCIENCES EQUITY OPTION Put 100 11 n/a n/a n/a
2023-11-14 2023-09-30 13F GILEAD SCIENCES EQUITY OPTION Put 0 -100.00 0 -100.00 n/a n/a n/a
2023-08-14 2023-06-30 13F GILEAD SCIENCES EQUITY OPTION Put 191,200 14,736 n/a n/a n/a
2023-05-15 2023-03-31 13F GILEAD SCIENCES EQUITY OPTION Put 0 -100.00 0 -100.00 n/a n/a n/a
2023-02-14 2022-12-31 13F GILEAD SCIENCES EQUITY OPTION Put 37,400 8.72 3,211 51.27 n/a n/a n/a
2022-11-14 2022-09-30 13F GILEAD SCIENCES EQUITY OPTION Put 34,400 2,122 n/a n/a n/a
2022-05-16 2022-03-31 13F March 22 Puts on GILD US at 60, American EQUITY OPTION Put 0 -100.00 0 -100.00 n/a n/a n/a
2022-02-14 2021-12-31 13F March 22 Puts on GILD US at 60, American EQUITY OPTION Put 59,600 -43.40 4,329 -41.14 n/a n/a n/a
2021-11-15 2021-09-30 13F October 21 Puts on GILD US at 72, American EQUITY OPTION Put 105,300 542.07 7,355 550.88 n/a n/a n/a
2021-08-13 2021-06-30 13F July 21 Puts on GILD US at 68, American EQUITY OPTION Put 16,400 1,130 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.