Costco Wholesale Corporation
MX ˙ BMV ˙ US22160K1051
SecurityMX:COST / Costco Wholesale Corporation
InstitutionRossmore Private Capital
Latest Disclosed Ownership7,667 shares
Latest Disclosed Value $ 7,639,729
Rossmore Private Capital reports 0.84% increase in ownership of COST / Costco Wholesale Corporation

On May 1, 2026 - Rossmore Private Capital filed a 13F-HR form disclosing ownership of 7,667 shares of Costco Wholesale Corporation (MX:COST) valued at $7,639,729 USD as of March 31, 2026. The entity filed a previous 13F-HR on February 5, 2026 disclosing 7,603 shares of Costco Wholesale Corporation. This represents a change in shares of 0.84% 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)
2026-05-01 2026-03-31 13F COSTCO WHOLESALE COM 22160K105 7,667 64 0.84 7,640 16.52 0.6703
2026-02-05 2025-12-31 13F COSTCO WHSL CORP COM 22160K105 7,603 800 11.76 6,556 4.11 0.5839
2025-10-30 2025-09-30 13F COSTCO WHSL CORP COM 22160K105 6,803 108 1.61 6,297 -4.98 0.6785
2025-08-07 2025-06-30 13F COSTCO WHSL CORP COM 22160K105 6,695 8 0.12 6,628 4.79 0.7737
2025-05-13 2025-03-31 13F COSTCO WHSL CORP COM 22160K105 6,687 62 0.94 6,325 4.18 0.7786
2025-02-13 2024-12-31 13F COSTCO WHSL CORP COM 22160K105 6,625 146 2.25 6,070 5.69 0.7505
2024-11-05 2024-09-30 13F COSTCO WHSL CORP COM 22160K105 6,479 -9 -0.14 5,744 4.15 0.7097
2024-08-12 2024-06-30 13F COSTCO WHSL CORP COM 22160K105 6,488 -35 -0.54 5,515 15.40 0.7242
2024-05-13 2024-03-31 13F COSTCO WHSL CORP COM 22160K105 6,523 24 0.37 4,779 11.40 0.6252
2024-02-07 2023-12-31 13F COSTCO WHSL CORP COM 22160K105 6,499 48 0.74 4,290 17.70 0.6061
2023-11-13 2023-09-30 13F COSTCO WHSL CORP COM 22160K105 6,451 -50 -0.77 3,645 4.11 0.5521
2023-08-14 2023-06-30 13F COSTCO WHSL CORP COM 22160K105 6,501 37 0.57 3,500 9.00 0.5207
2023-05-02 2023-03-31 13F COSTCO WHSL CORP COM 22160K105 6,464 -60 -0.92 3,212 8.26 0.5017
2023-02-14 2022-12-31 13F COSTCO WHSL CORP COM 22160K105 6,524 84 1.30 2,967 98,766.67 0.4750
2022-11-08 2022-09-30 13F COSTCO WHSL CORP COM 22160K105 6,440 35 0.55 3 0.00 0.5442
2022-08-11 2022-06-30 13F COSTCO WHSL CORP COM 22160K105 6,405 -25 -0.39 3 0.00 0.5315
2022-05-09 2022-03-31 13F COSTCO WHSL CORP COM 22160K105 6,430 -25 -0.39 4 0.00 0.5766
2022-02-07 2021-12-31 13F COSTCO WHSL CORP COM 22160K105 6,455 50 0.78 4 50.00 0.5723
2021-11-08 2021-09-30 13F COSTCO WHSL CORP COM 22160K105 6,405 75 1.18 3 0.00 0.4928
2021-08-13 2021-06-30 13F COSTCO WHSL CORP COM 22160K105 6,330 240 3.94 3 0.00 0.4287
2021-05-10 2021-03-31 13F COSTCO WHSL CORP COM 22160K105 6,090 68 1.13 2 0.00 0.4025
2021-02-10 2020-12-31 13F COSTCO WHSL CORP COM 22160K105 6,022 42 0.70 2 0.00 0.4600
2020-11-10 2020-09-30 13F COSTCO WHSL CORP COM 22160K105 5,980 365 6.50 2 -99.88 0.4989
2020-08-05 2020-06-30 13F COSTCO WHSL CORP COM 22160K105 5,615 1,537 37.69 1,703 46.43 0.4703
2020-05-07 2020-03-31 13F COSTCO WHSL CORP COM 22160K105 4,078 1,445 54.88 1,163 50.26 0.4021
2020-02-10 2019-12-31 13F COSTCO WHSL CORP COM 22160K105 2,633 0 0.00 774 1.98 0.2388
2019-11-05 2019-09-30 13F COSTCO WHSL CORP COM 22160K105 2,633 0 0.00 759 9.05 0.2552
2019-08-05 2019-06-30 13F COSTCO WHSL CORP COM 22160K105 2,633 0 0.00 696 9.09 0.2459
2019-04-30 2019-03-31 13F COSTCO WHSL CORP COM 22160K105 2,633 -25 -0.94 638 17.93 0.2349
2019-01-22 2018-12-31 13F COSTCO WHSL CORP COM 22160K105 2,658 225 9.25 541 -5.25 0.2293
2018-10-26 2018-09-30 13F COSTCO WHSL CORP COM 22160K105 2,433 0 0.00 571 12.40 0.2283
2018-07-20 2018-06-30 13F COSTCO WHSL CORP COM 22160K105 2,433 0 0.00 508 10.92 0.3279
2018-05-04 2018-03-31 13F COSTCO WHSL CORP COM 22160K105 2,433 163 7.18 458 8.53 0.4636
2018-03-15 2017-12-31 13F COSTCO WHOLESALE CORP NEW COM COM 22160K105 2,270 2,270 422 0.4257
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.