Costco Wholesale Corporation
US ˙ NasdaqGS ˙ US22160K1051

SecurityCOST / Costco Wholesale Corporation
InstitutionMcIlrath & Eck, LLC
Latest Disclosed Ownership6,485 shares
Latest Disclosed Value $ 6,462,069
McIlrath & Eck, LLC reports 1.00% increase in ownership of COST / Costco Wholesale Corporation

On May 19, 2026 - McIlrath & Eck, LLC filed a 13F-HR form disclosing ownership of 6,485 shares of Costco Wholesale Corporation (US:COST) valued at $6,461,849 USD as of March 31, 2026. The entity filed a previous 13F-HR on February 3, 2026 disclosing 6,421 shares of Costco Wholesale Corporation. This represents a change in shares of 1.00% during the quarter. The current value of the position is $6,237,468 USD.

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)
2026-05-19 2026-03-31 13F COSTCO WHSL CORP NEW COM COMMON STOCK 22160K105 6,485 64 1.00 6,462 16.71 0.4790
2026-02-03 2025-12-31 13F COSTCO WHSL CORP COM 22160K105 6,421 -16 -0.25 5,537 -7.07 0.5144
2025-10-22 2025-09-30 13F COSTCO WHSL CORP OM 22160K105 6,437 209 3.36 5,958 -3.36 0.6153
2025-08-14 2025-06-30 13F COSTCO WHSL CORP COM 22160K105 6,228 3,530 130.84 6,165 141.67 0.7037
2025-05-16 2025-03-31 13F COSTCO WHSL CORP COM 22160K105 2,698 -28 -1.03 2,551 2.16 0.3133
2025-02-18 2024-12-31 13F COSTCO WHSL CORP COM 22160K105 2,726 -3,703 -57.60 2,497 -56.19 0.3184
2024-11-19 2024-09-30 13F COSTCO WHSL CORP COM 22160K105 6,429 -72 -1.11 5,699 3.13 0.7341
2024-08-14 2024-06-30 13F COSTCO WHSL CORP COM 22160K105 6,501 7 0.11 5,526 16.14 0.8207
2024-05-10 2024-03-31 13F COSTCO WHSL CORP COM 22160K105 6,494 3,755 137.09 4,758 163.16 0.7538
2024-02-06 2023-12-31 13F COSTCO WHSL CORP COM 22160K105 2,739 143 5.51 1,808 23.33 0.3178
2023-11-16 2023-09-30 13F COSTCO WHSL CORP COM 22160K105 2,596 -25 -0.95 1,467 3.90 0.2949
2023-08-07 2023-06-30 13F COSTCO WHSL CORP COM 22160K105 2,621 328 14.30 1,411 23.88 0.2958
2023-05-09 2023-03-31 13F COSTCO WHSL CORP COM 22160K105 2,293 -12 -0.52 1,139 8.27 0.2660
2023-02-15 2022-12-31 13F COSTCO WHSL CORP COM 22160K105 2,305 -13,270 -85.20 1,052 -85.70 0.2710
2022-10-18 2022-09-30 13F COSTCO WHSL CORP COM 22160K105 15,575 -69 -0.44 7,356 -1.89 2.0220
2022-07-29 2022-06-30 13F COSTCO WHSL CORP COM 22160K105 15,644 13,330 576.06 7,498 462.49 2.3299
2022-05-11 2022-03-31 13F COSTCO WHSL CORP COM 22160K105 2,314 1 0.04 1,333 1.52 0.3856
2022-02-08 2021-12-31 13F COSTCO WHSL CORP COM 22160K105 2,313 -10 -0.43 1,313 25.77 0.3550
2021-11-12 2021-09-30 13F COSTCO WHSL CORP COM 22160K105 2,323 -91 -3.77 1,044 9.32 0.3108
2021-08-09 2021-06-30 13F COSTCO WHSL CORP COM 22160K105 2,414 -1,713 -41.51 955 -34.36 0.2902
2021-05-12 2021-03-31 13F COSTCO WHSL CORP COM 22160K105 4,127 -98 -2.32 1,455 -8.61 0.5069
2021-02-05 2020-12-31 13F COSTCO WHSL CORP COM 22160K105 4,225 86 2.08 1,592 8.37 0.5888
2020-11-13 2020-09-30 13F COSTCO WHSL CORP COM 22160K105 4,139 83 2.05 1,469 19.43 0.6284
2020-08-04 2020-06-30 13F COSTCO WHSL CORP COM 22160K105 4,056 219 5.71 1,230 12.43 0.5699
2020-05-14 2020-03-31 13F COSTCO WHSL CORP COM 22160K105 3,837 758 24.62 1,094 20.88 0.6094
2020-02-11 2019-12-31 13F COSTCO WHSL CORP COM 22160K105 3,079 396 14.76 905 17.08 0.4341
2019-11-05 2019-09-30 13F COSTCO WHSL CORP COM 22160K105 2,683 235 9.60 773 30.35 0.4082
2019-08-08 2019-06-30 13F COSTCO WHSL CORP COM 22160K105 2,448 0 0.00 593 0.00 0.3288
2019-05-07 2019-03-31 13F COSTCO WHSL CORP COM 22160K105 2,448 453 22.71 593 46.06 0.3288
2019-05-07 2018-12-31 13F COSTCO WHSL CORP COM 22160K105 1,995 341 20.62 406 4.37 0.2603
2018-11-13 2018-09-30 13F COSTCO WHSL CORP COM 22160K105 1,654 69 4.35 389 17.52 0.2240
2018-08-06 2018-06-30 13F COSTCO WHSL CORP COM 22160K105 1,585 228 16.80 331 29.30 0.2010
2018-05-21 2018-03-31 13F COSTCO WHSL CORP COM 22160K105 1,357 -618 -31.29 256 -30.25 0.1499
2018-03-16 2017-12-31 13F COSTCO WHOLESALE CORP NEW COM Common 22160K105 1,975 1,975 367 0.2150
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.