Costco Wholesale Corporation
MX ˙ BMV ˙ US22160K1051
SecurityMX:COST / Costco Wholesale Corporation
InstitutionChesapeake Wealth Management
Latest Disclosed Ownership670 shares
Latest Disclosed Value $ 667,608
Chesapeake Wealth Management reports 11.48% increase in ownership of COST / Costco Wholesale Corporation

On May 18, 2026 - Chesapeake Wealth Management filed a 13F-HR form disclosing ownership of 670 shares of Costco Wholesale Corporation (MX:COST) valued at $667,608 USD as of March 31, 2026. The entity filed a previous 13F-HR on February 3, 2026 disclosing 601 shares of Costco Wholesale Corporation. This represents a change in shares of 11.48% 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.

Upgrade to unlock premium data and export to Excel .

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)
2026-05-18 2026-03-31 13F COSTCO WHOLESALE COM 22160K105 670 69 11.48 668 28.76 0.1148
2026-02-03 2025-12-31 13F COSTCO WHSL CORP COM 22160K105 601 -17 -2.75 518 -9.44 0.1544
2025-11-03 2025-09-30 13F COSTCO WHSL CORP COM 22160K105 618 -5 -0.80 572 -7.14 0.1745
2025-07-28 2025-06-30 13F COSTCO WHSL CORP COM 22160K105 623 0 0.00 617 4.58 0.2057
2025-05-08 2025-03-31 13F COSTCO WHSL CORP COM 22160K105 623 -17 -2.66 589 0.51 0.2102
2025-01-16 2024-12-31 13F COSTCO WHSL CORP COM 22160K105 640 -39 -5.74 586 -2.50 0.2011
2024-11-07 2024-09-30 13F COSTCO WHSL CORP COM 22160K105 679 -7 -1.02 602 3.09 0.2054
2024-08-13 2024-06-30 13F COSTCO WHSL CORP COM 22160K105 686 117 20.56 583 40.14 0.2115
2024-05-07 2024-03-31 13F COSTCO WHSL CORP COM 22160K105 569 -46 -7.48 417 2.72 0.1520
2024-02-12 2023-12-31 13F COSTCO WHSL CORP COM 22160K105 615 0 0.00 406 16.71 0.1567
2023-11-16 2023-09-30 13F COSTCO WHSL CORP COM 22160K105 615 0 0.00 347 4.83 0.1449
2023-08-01 2023-06-30 13F COSTCO WHSL CORP COM 22160K105 615 615 331 0.1305
2022-10-28 2022-09-30 13F COSTCO WHSL CORP COM 22160K105 0 -427 -100.00 0 -100.00
2022-07-21 2022-06-30 13F COSTCO WHSL CORP COM 22160K105 427 37 9.49 205 -8.89 0.0877
2022-04-19 2022-03-31 13F COSTCO WHSL CORP COM 22160K105 390 0 0.00 225 1.81 0.0817
2022-02-03 2021-12-31 13F COSTCO WHSL CORP COM 22160K105 390 -84 -17.72 221 3.76 0.0744
2021-10-26 2021-09-30 13F COSTCO WHSL CORP COM 22160K105 474 474 213 0.0762
2021-04-26 2021-03-31 13F COSTCO WHSL CORP COM 22160K105 0 -628 -100.00 0 -100.00
2021-02-05 2020-12-31 13F COSTCO WHSL CORP COM 22160K105 628 -20 -3.09 237 3.04 0.0807
2020-11-12 2020-09-30 13F COSTCO WHSL CORP COM 22160K105 648 648 230 0.0859
2020-01-29 2019-12-31 13F COSTCO WHSL CORP COM 22160K105 0 -728 -100.00 0 -100.00
2019-10-25 2019-09-30 13F COSTCO WHSL CORP COM 22160K105 728 728 210 0.0856
2019-08-01 2019-06-30 13F COSTCO WHSL CORP COM 22160K105 0 -971 -100.00 0 -100.00
2019-04-17 2019-03-31 13F COSTCO WHSL CORP COM 22160K105 971 -2,251 -69.86 235 -64.18 0.1033
2019-02-06 2018-12-31 13F COSTCO WHSL CORP COM 22160K105 3,222 723 28.93 656 11.75 0.3248
2018-11-14 2018-09-30 13F COSTCO WHSL CORP COM 22160K105 2,499 2,499 587 0.2610
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.