Costco Wholesale Corporation
MX ˙ BMV ˙ US22160K1051
SecurityMX:COST / Costco Wholesale Corporation
InstitutionMarshall Wace, Llp
Latest Disclosed Ownership263,741 shares
Latest Disclosed Value $ 262,799,444
Marshall Wace, Llp ownership in COST / Costco Wholesale Corporation

On May 14, 2026 - Marshall Wace, Llp filed a 13F-HR form disclosing ownership of 263,741 shares of Costco Wholesale Corporation (MX:COST) valued at $262,799,444 USD as of March 31, 2026. The entity filed a previous 13F-HR on February 13, 2026 disclosing 512,030 shares of Costco Wholesale Corporation. This represents a change in shares of -48.49% during the quarter.

Marshall Wace, Llp has a history of taking positions in derivatives of the underlying security (COST) in the form of stock options. The firm currently holds call options representing 600 of underlying shares valued at $597,858 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.

MX:COST / Costco Wholesale Corporation 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 COSTCO WHOLESALE COMMON STOCK 22160K105 263,741 -248,289 -48.49 262,799 -40.48 0.1240
2026-02-13 2025-12-31 13F COSTCO WHOLESALE COMMON STOCK 22160K105 512,030 420,985 462.39 441,544 423.94 0.4019
2025-11-13 2025-09-30 13F COSTCO WHOLESALE COMMON STOCK 22160K105 91,045 -232,446 -71.86 84,274 -73.68 0.0855
2025-08-13 2025-06-30 13F COSTCO WHOLESALE COMMON STOCK 22160K105 323,491 -222,556 -40.76 320,237 -37.99 0.3607
2025-05-15 2025-03-31 13F COSTCO WHOLESALE COMMON STOCK 22160K105 546,047 442,970 429.75 516,440 446.81 0.6557
2025-02-13 2024-12-31 13F COSTCO WHOLESALE COMMON STOCK 22160K105 103,077 101,099 5,111.17 94,446 5,287.68 0.1135
2024-11-14 2024-09-30 13F COSTCO WHOLESALE COMMON STOCK 22160K105 1,978 -570,384 -99.65 1,754 -99.64 0.0021
2024-08-14 2024-06-30 13F COSTCO WHOLESALE COMMON STOCK 22160K105 572,362 -84,847 -12.91 486,502 1.04 0.6496
2024-05-15 2024-03-31 13F COSTCO WHOLESALE COMMON STOCK 22160K105 657,209 201,970 44.37 481,491 60.23 0.7332
2024-02-14 2023-12-31 13F COSTCO WHOLESALE COMMON STOCK 22160K105 455,239 -130,568 -22.29 300,494 -9.20 0.5089
2023-11-14 2023-09-30 13F COSTCO WHOLESALE COMMON STOCK 22160K105 585,807 512,787 702.26 330,958 741.87 0.6703
2023-08-14 2023-06-30 13F COSTCO WHOLESALE COMMON STOCK 22160K105 73,020 72,072 7,602.53 39,313 8,246.50 0.0768
2023-05-15 2023-03-31 13F COSTCO WHOLESALE COMMON STOCK 22160K105 948 -136,023 -99.31 471 -99.25 0.0010
2023-02-14 2022-12-31 13F COSTCO WHOLESALE COMMON STOCK 22160K105 136,971 -227,374 -62.41 62,527 -63.66 0.1406
2022-11-14 2022-09-30 13F COSTCO WHOLESALE COMMON STOCK 22160K105 364,345 226,239 163.82 172,070 159.96 0.3770
2022-08-15 2022-06-30 13F COSTCO WHOLESALE COMMON STOCK 22160K105 138,106 -263,635 -65.62 66,192 -71.39 0.1362
2022-05-16 2022-03-31 13F COSTCO WHOLESALE COMMON STOCK 22160K105 401,741 385,141 2,320.13 231,343 2,355.61 0.4381
2022-02-14 2021-12-31 13F COSTCO WHOLESALE COMMON STOCK 22160K105 16,600 -5,806 -25.91 9,421 -6.43 0.0174
2021-11-15 2021-09-30 13F COSTCO WHOLESALE COMMON STOCK 22160K105 22,406 5,189 30.14 10,068 47.80 0.0418
2021-08-13 2021-06-30 13F COSTCO WHOLESALE COMMON STOCK 22160K105 17,217 -37,185 -68.35 6,812 -64.48 0.0332
2021-05-17 2021-03-31 13F COSTCO WHOLESALE COMMON STOCK 22160K105 54,402 -12,918 -19.19 19,177 -24.40 0.0879
2021-02-16 2020-12-31 13F COSTCO WHOLESALE COMMON STOCK 22160K105 67,320 -56,693 -45.72 25,365 -42.39 0.1374
2020-11-16 2020-09-30 13F COSTCO WHOLESALE COMMON STOCK 22160K105 124,013 108,377 693.12 44,025 828.60 0.2818
2020-08-13 2020-06-30 13F COSTCO WHOLESALE COMMON STOCK 22160K105 15,636 -66,448 -80.95 4,741 -79.74 0.0332
2020-05-15 2020-03-31 13F COSTCO WHOLESALE LONG COMMON STOCK 22160K105 82,084 -187,100 -69.51 23,405 -70.42 0.2338
2020-02-14 2019-12-31 13F COSTCO WHOLESALE LONG COMMON STOCK 22160K105 269,184 64,794 31.70 79,119 34.36 0.5438
2019-11-14 2019-09-30 13F COSTCO WHOLESALE COMMON STOCK 22160K105 204,390 183,442 875.70 58,886 963.69 0.4629
2019-08-14 2019-06-30 13F COSTCO WHOLESALE COMMON STOCK 22160K105 20,948 3,021 16.85 5,536 27.53 0.0455
2019-05-29 2019-03-31 13F/A-1 COSTCO WHOLESALE COMMON STOCK 22160K105 17,927 15,733 717.09 4,341 871.14 0.0408
2019-05-14 2019-03-31 13F COSTCO WHOLESALE COMMON STOCK 22160K105 17,927 15,733 4,341
2019-02-14 2018-12-31 13F COSTCO WHOLESALE COMMON STOCK 22160K105 2,194 2,194 -87.76 447 -89.70 0.0046
2018-11-14 2018-09-30 13F COSTCO WHOLESALE COMMON STOCK 22160K105 0 -250,388 -100.00 0 -100.00
2018-08-14 2018-06-30 13F COSTCO WHOLESALE COMMON STOCK 22160K105 250,388 235,505 1,582.38 52,326 1,766.12 0.7829
2018-05-15 2018-03-31 13F COSTCO WHOLESALE COMMON STOCK 22160K105 14,883 14,883 -94.06 2,804 -94.64 0.1162
2017-05-12 2017-03-31 13F COSTCO WHOLESALE COMMON STOCK 22160K105 0 -220,295 -100.00 0 -100.00
2017-02-10 2016-12-31 13F COSTCO WHOLESALE COMMON STOCK 22160K105 220,295 48,151 27.97 35,273 34.35 0.2319
2016-11-10 2016-09-30 13F COSTCO WHOLESALE COMMON STOCK 22160K105 172,144 169,718 6,995.80 26,254 6,790.81 0.1867
2016-08-12 2016-06-30 13F COSTCO WHOLESALE COMMON STOCK 22160K105 2,426 -3,080 -55.94 381 -56.11 0.0032
2016-05-13 2016-03-31 13F COSTCO WHOLESALE COMMON STOCK 22160K105 5,506 -6,785 -55.20 868 -56.27 0.0084
2016-02-10 2015-12-31 13F COSTCO WHOLESALE COMMON STOCK 22160K105 12,291 12,291 123.23 1,985 128.69 0.0186
2014-11-13 2014-09-30 13F COSTCO WHOLESALE COMMON STOCK 22160K105 0 -45,836 -100.00 0 -100.00
2014-08-14 2014-06-30 13F COSTCO WHOLESALE COMMON STOCK 22160K105 45,836 -10,598 -18.78 5,278 -16.26 0.0777
2014-05-14 2014-03-31 13F COSTCO WHOLESALE COMMON STOCK 22160K105 56,434 56,434 6,303 0.1146
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 COSTCO WHOLESALE EQUITY OPTION Call 600 -77.78 598 -74.36 n/a n/a n/a
2026-02-13 2025-12-31 13F COSTCO WHOLESALE EQUITY OPTION Call 2,700 -6.90 2,328 -13.26 n/a n/a n/a
2025-11-13 2025-09-30 13F COSTCO WHOLESALE EQUITY OPTION Call 2,900 2,684 n/a n/a n/a
2025-08-13 2025-06-30 13F COSTCO WHOLESALE EQUITY OPTION Call 0 -100.00 0 -100.00 n/a n/a n/a
2025-05-15 2025-03-31 13F COSTCO WHOLESALE EQUITY OPTION Call 300 284 n/a n/a n/a
2024-11-14 2024-09-30 13F COSTCO WHOLESALE EQUITY OPTION Call 0 -100.00 0 -100.00 n/a n/a n/a
2024-08-14 2024-06-30 13F COSTCO WHOLESALE EQUITY OPTION Call 1,900 -89.08 1,615 -88.08 n/a n/a n/a
2024-05-15 2024-03-31 13F COSTCO WHOLESALE EQUITY OPTION Call 17,400 100.00 13,535 135.72 n/a n/a n/a
2024-02-14 2023-12-31 13F COSTCO WHOLESALE EQUITY OPTION Call 8,700 -69.15 5,743 -63.96 n/a n/a n/a
2023-11-14 2023-09-30 13F COSTCO WHOLESALE EQUITY OPTION Call 28,200 58.43 15,932 66.24 n/a n/a n/a
2023-08-14 2023-06-30 13F COSTCO WHOLESALE EQUITY OPTION Call 17,800 -69.36 9,583 -66.80 n/a n/a n/a
2023-05-15 2023-03-31 13F COSTCO WHOLESALE EQUITY OPTION Call 58,100 -27.74 28,868 -21.34 n/a n/a n/a
2023-02-14 2022-12-31 13F COSTCO WHOLESALE EQUITY OPTION Call 80,400 88.73 36,703 82.51 n/a n/a n/a
2022-11-14 2022-09-30 13F COSTCO WHOLESALE EQUITY OPTION Call 42,600 47.40 20,110 45.17 n/a n/a n/a
2022-08-15 2022-06-30 13F July 22 Calls on COST US at 485, American EQUITY OPTION Call 28,900 97.95 13,853 64.74 n/a n/a n/a
2022-05-16 2022-03-31 13F April 22 Calls on COST US at 560, American EQUITY OPTION Call 14,600 23.73 8,409 25.53 n/a n/a n/a
2022-02-14 2021-12-31 13F January 22 Calls on COST US at 575, American EQUITY OPTION Call 11,800 21.65 6,699 53.68 n/a n/a n/a
2021-11-15 2021-09-30 13F October 21 Calls on COST US at 460, American EQUITY OPTION Call 9,700 -9.35 4,359 2.95 n/a n/a n/a
2021-08-13 2021-06-30 13F July 21 Calls on COST US at 397.5, American EQUITY OPTION Call 10,700 4,234 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 COSTCO WHOLESALE EQUITY OPTION Put 0 -100.00 0 -100.00 n/a n/a n/a
2026-02-13 2025-12-31 13F COSTCO WHOLESALE EQUITY OPTION Put 39,700 -56.08 34,235 -59.09 n/a n/a n/a
2025-11-13 2025-09-30 13F COSTCO WHOLESALE EQUITY OPTION Put 90,400 659.66 83,677 610.32 n/a n/a n/a
2025-08-13 2025-06-30 13F COSTCO WHOLESALE EQUITY OPTION Put 11,900 11,780 n/a n/a n/a
2025-05-15 2025-03-31 13F COSTCO WHOLESALE EQUITY OPTION Put 0 -100.00 0 -100.00 n/a n/a n/a
2025-02-13 2024-12-31 13F COSTCO WHOLESALE EQUITY OPTION Put 300 -91.18 275 -90.91 n/a n/a n/a
2024-11-14 2024-09-30 13F COSTCO WHOLESALE EQUITY OPTION Put 3,400 277.78 3,014 294.50 n/a n/a n/a
2024-08-14 2024-06-30 13F COSTCO WHOLESALE EQUITY OPTION Put 900 -96.25 765 -95.91 n/a n/a n/a
2024-05-15 2024-03-31 13F COSTCO WHOLESALE EQUITY OPTION Put 24,000 410.64 18,670 501.84 n/a n/a n/a
2024-02-14 2023-12-31 13F COSTCO WHOLESALE EQUITY OPTION Put 4,700 -86.94 3,102 -84.75 n/a n/a n/a
2023-11-14 2023-09-30 13F COSTCO WHOLESALE EQUITY OPTION Put 36,000 -44.95 20,339 -42.24 n/a n/a n/a
2023-08-14 2023-06-30 13F COSTCO WHOLESALE EQUITY OPTION Put 65,400 -24.91 35,210 -18.64 n/a n/a n/a
2023-05-15 2023-03-31 13F COSTCO WHOLESALE EQUITY OPTION Put 87,100 -29.70 43,277 -23.48 n/a n/a n/a
2023-02-14 2022-12-31 13F COSTCO WHOLESALE EQUITY OPTION Put 123,900 300.97 56,560 287.80 n/a n/a n/a
2022-11-14 2022-09-30 13F COSTCO WHOLESALE EQUITY OPTION Put 30,900 64.36 14,585 61.79 n/a n/a n/a
2022-08-15 2022-06-30 13F January 23 Puts on COST US at 380, American EQUITY OPTION Put 18,800 72.48 9,015 43.60 n/a n/a n/a
2022-05-16 2022-03-31 13F April 22 Puts on COST US at 565, American EQUITY OPTION Put 10,900 -30.57 6,278 -29.56 n/a n/a n/a
2022-02-14 2021-12-31 13F January 22 Puts on COST US at 560, American EQUITY OPTION Put 15,700 8,913 n/a n/a n/a
2021-11-15 2021-09-30 13F July 21 Puts on COST US at 395, American EQUITY OPTION Put 0 -100.00 0 -100.00 n/a n/a n/a
2021-08-13 2021-06-30 13F July 21 Puts on COST US at 395, American EQUITY OPTION Put 4,000 1,582 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.