Costco Wholesale Corporation
MX ˙ BMV ˙ US22160K1051
SecurityMX:COST / Costco Wholesale Corporation
InstitutionField & Main Bank
Latest Disclosed Ownership4,500 shares
Latest Disclosed Value $ 4,483,935
Field & Main Bank reports 1.08% decrease in ownership of COST / Costco Wholesale Corporation

On April 10, 2026 - Field & Main Bank filed a 13F-HR form disclosing ownership of 4,500 shares of Costco Wholesale Corporation (MX:COST) valued at $4,483,935 USD as of March 31, 2026. The entity filed a previous 13F-HR on January 28, 2026 disclosing 4,549 shares of Costco Wholesale Corporation. This represents a change in shares of -1.08% during the quarter.

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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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)
2026-04-10 2026-03-31 13F Costco Whsl Com 22160K105 4,500 -49 -1.08 4,484 14.30 0.7538
2026-01-28 2025-12-31 13F Costco Whsl Com 22160K105 4,549 91 2.04 3,923 -4.94 1.1303
2025-11-03 2025-09-30 13F COSTCO WHSL CORP COMMON STOCK - LARGE CAP 22160K105 4,458 -74 -1.63 4,126 -8.02 1.2188
2025-08-04 2025-06-30 13F COSTCO WHSL CORP COMMON STOCK - LARGE CAP 22160K105 4,532 -84 -1.82 4,486 2.77 1.4595
2025-04-23 2025-03-31 13F COSTCO WHSL CORP COMMON STOCK - LARGE CAP 22160K105 4,616 -218 -4.51 4,366 -1.45 1.5416
2025-01-23 2024-12-31 13F COSTCO WHSL CORP COMMON STOCK - LARGE CAP 22160K105 4,834 -58 -1.19 4,429 2.14 1.5581
2024-11-01 2024-09-30 13F COSTCO WHSL CORP COMMON STOCK - LARGE CAP 22160K105 4,892 -136 -2.70 4,337 1.47 1.5453
2024-07-25 2024-06-30 13F COSTCO WHSL CORP COMMON STOCK - LARGE CAP 22160K105 5,028 -68 -1.33 4,274 14.47 1.6004
2024-04-29 2024-03-31 13F COSTCO WHSL CORP COMMON STOCK - LARGE CAP 22160K105 5,096 -125 -2.39 3,733 8.33 1.4503
2024-02-05 2023-12-31 13F COSTCO WHSL CORP COMMON STOCK - LARGE CAP 22160K105 5,221 51 0.99 3,446 18.01 1.4574
2023-10-12 2023-09-30 13F COSTCO WHSL CORP COMMON STOCK - LARGE CAP 22160K105 5,170 -29 -0.56 2,921 4.36 1.3678
2023-07-26 2023-06-30 13F COSTCO WHSL CORP COMMON STOCK - LARGE CAP 22160K105 5,199 -81 -1.53 2,799 6.67 1.5598
2023-04-19 2023-03-31 13F COSTCO WHSL CORP COMMON STOCK - LARGE CAP 22160K105 5,280 137 2.66 2,623 11.76 1.5647
2023-01-19 2022-12-31 13F COSTCO WHSL CORP COMMON STOCK - LARGE CAP 22160K105 5,143 -36 -0.70 2,348 -4.05 1.5136
2022-10-25 2022-09-30 13F COSTCO WHSL CORP COMMON STOCK - LARGE CAP 22160K105 5,179 120 2.37 2,446 0.87 1.6425
2022-07-18 2022-06-30 13F COSTCO WHSL CORP COMMON STOCK - LARGE CAP 22160K105 5,059 90 1.81 2,425 -15.24 1.5608
2022-04-21 2022-03-31 13F COSTCO WHSL CORP COMMON STOCK - LARGE CAP 22160K105 4,969 5 0.10 2,861 1.53 1.7314
2022-02-01 2021-12-31 13F COSTCO WHSL CORP COMMON STOCK - LARGE CAP 22160K105 4,964 392 8.57 2,818 37.20 1.6248
2021-10-14 2021-09-30 13F COSTCO WHSL CORP COMMON STOCK - LARGE CAP 22160K105 4,572 -183 -3.85 2,054 9.20 1.3508
2021-07-15 2021-06-30 13F COSTCO WHSL CORP COMMON STOCK - LARGE CAP 22160K105 4,755 140 3.03 1,881 15.61 1.2050
2021-04-30 2021-03-31 13F COSTCO WHSL CORP COMMON STOCK - LARGE CAP 22160K105 4,615 -10 -0.22 1,627 -6.66 1.1672
2021-02-25 2020-12-31 13F COSTCO WHSL CORP COMMON STOCK - LARGE CAP 22160K105 4,625 -341 -6.87 1,743 -1.13 1.2971
2020-10-22 2020-09-30 13F COSTCO WHSL CORP COMMON STOCK - LARGE CAP 22160K105 4,966 130 2.69 1,763 20.26 1.3620
2020-08-12 2020-06-30 13F COSTCO WHSL CORP COMMON STOCK - LARGE CAP 22160K105 4,836 305 6.73 1,466 10.06 1.2490
2020-02-05 2019-12-31 13F/A-1 COSTCO WHSL CORP COMMON STOCK - LARGE CAP 22160K105 4,531 15 0.33 1,332 2.38 1.1065
2020-02-03 2019-12-31 13F COSTCO WHSL CORP COMMON STOCK - LARGE CAP 22160K105 4,531 15 1,332 811,344.2000
2019-11-07 2019-09-30 13F COSTCO WHSL CORP COMMON STOCK - LARGE CAP 22160K105 4,516 290 6.86 1,301 16.47 1.1732
2019-07-22 2019-06-30 13F COSTCO WHSL CORP COMMON STOCK - LARGE CAP 22160K105 4,226 215 5.36 1,117 15.04 1.0251
2019-04-24 2019-03-31 13F COSTCO WHSL CORP COMMON STOCK - LARGE CAP 22160K105 4,011 253 6.73 971 9.97 0.9161
2018-10-23 2018-09-30 13F COSTCO WHSL CORP COMMON STOCK - LARGE CAP 22160K105 3,758 -41 -1.08 883 6.26 0.7886
2018-08-13 2018-06-30 13F COSTCO WHSL CORP COMMON STOCK - LARGE CAP 22160K105 3,799 38 1.01 831 17.21 0.7568
2018-05-01 2018-03-31 13F COSTCO WHSL CORP COMMON STOCK - LARGE CAP 22160K105 3,761 75 2.03 709 3.35 0.6916
2018-01-24 2017-12-31 13F COSTCO WHSL CORP COMMON STOCK - LARGE CAP 22160K105 3,686 3,342 971.51 686 1,391.30 0.6581
2015-07-22 2015-06-30 13F COSTCO WHSL CORP COMMON STOCK - LARGE CAP 22160K105 344 0 0.00 46 -11.54 0.0437
2015-04-30 2015-03-31 13F COSTCO WHSL CORP COMMON STOCK - LARGE CAP 22160K105 344 344 52 0.0481
2015-02-03 2014-12-31 13F COSTCO WHSL CORP COMMON STOCK - LARGE CAP 22160K105 0 -194 -100.00 0 -100.00
2014-10-14 2014-09-30 13F COSTCO WHSL CORP COMMON STOCK - LARGE CAP 22160K105 194 0 0.00 24 9.09 0.0226
2014-08-11 2014-06-30 13F COSTCO WHSL CORP COMMON STOCK - LARGE CAP 22160K105 194 0 0.00 22 0.00 0.0206
2014-04-17 2014-03-31 13F COSTCO WHSL CORP COMMON STOCK - LARGE CAP 22160K105 194 0 0.00 22 -4.35 0.0213
2014-02-13 2013-12-31 13F COSTCO WHSL CORP COMMON STOCK - LARGE CAP 22160K105 194 194 23 0.0224
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.