Costco Wholesale Corporation
MX ˙ BMV ˙ US22160K1051
SecurityMX:COST / Costco Wholesale Corporation
InstitutionBaird Financial Group, Inc.
Latest Disclosed Ownership615,148 shares
Latest Disclosed Value $ 612,952,572
Baird Financial Group, Inc. reports 2.85% increase in ownership of COST / Costco Wholesale Corporation

On May 14, 2026 - Baird Financial Group, Inc. filed a 13F-HR form disclosing ownership of 615,148 shares of Costco Wholesale Corporation (MX:COST) valued at $612,952,572 USD as of March 31, 2026. The entity filed a previous 13F-HR on February 13, 2026 disclosing 598,110 shares of Costco Wholesale Corporation. This represents a change in shares of 2.85% 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)
2026-05-14 2026-03-31 13F COSTCO WHOLESALE COM 22160K105 615,148 17,038 2.85 612,953 18.84 0.5153
2026-02-13 2025-12-31 13F COSTCO WHSL CORP NEW COM COMMON 22160K105 598,110 5,408 0.91 515,775 -5.99 0.8040
2025-11-13 2025-09-30 13F COSTCO WHOLESALE COMMON 22160K105 592,702 -8,867 -1.47 548,623 -7.87 0.8822
2025-08-13 2025-06-30 13F COSTCO WHSL CORP NEW COM COMMON 22160K105 601,569 -3,604 -0.60 595,517 4.05 1.0442
2025-05-15 2025-03-31 13F COSTCO WHSL CORP NEW COM COMMON 22160K105 605,173 -10,120 -1.64 572,361 1.52 1.1020
2025-02-14 2024-12-31 13F COSTCO WHSL CORP COMMON 22160K105 615,293 4,518 0.74 563,775 4.12 1.0782
2024-11-14 2024-09-30 13F COSTCO WHOLESALE COMMON 22160K105 610,775 -14,797 -2.37 541,465 1.83 1.0515
2024-08-14 2024-06-30 13F COSTCO WHSL CORP COMMON 22160K105 625,572 4,574 0.74 531,730 16.87 1.1030
2024-05-14 2024-03-31 13F COSTCO WHSL CORP COMMON 22160K105 620,998 -9,277 -1.47 454,962 9.36 0.9540
2024-02-14 2023-12-31 13F COSTCO WHSL CORP COMMON 22160K105 630,275 122,053 24.02 416,032 44.90 0.9481
2023-11-13 2023-09-30 13F COSTCO WHSL CORP COMMON 22160K105 508,222 3,593 0.71 287,125 5.68 0.7832
2023-08-11 2023-06-30 13F COSTCO WHSL CORP COMMON 22160K105 504,629 -99,326 -16.45 271,682 -9.47 0.7171
2023-05-15 2023-03-31 13F COSTCO WHSL CORP COMMON 22160K105 603,955 -860 -0.14 300,087 108,627.17 0.7402
2023-02-13 2022-12-31 13F COSTCO WHSL CORP COMMON 22160K105 604,815 -77,198 -11.32 276 -99.91 0.7270
2022-11-15 2022-09-30 13F COSTCO WHSL CORP COMMON 22160K105 682,013 -3,679 -0.54 322,094 -1.99 0.9490
2022-08-08 2022-06-30 13F COSTCO WHSL CORP COMMON 22160K105 685,692 -20,931 -2.96 328,639 -19.24 0.9123
2022-05-13 2022-03-31 13F COSTCO WHSL CORP COMMON 22160K105 706,623 2,118 0.30 406,909 1.74 1.0055
2022-02-09 2021-12-31 13F COSTCO WHSL CORP NEW COM COMMON 22160K105 704,505 1,710 0.24 399,947 26.65 0.9350
2021-11-12 2021-09-30 13F COSTCO WHSL CORP NEW COM COMMON 22160K105 702,795 9,028 1.30 315,801 15.04 0.8077
2021-08-11 2021-06-30 13F COSTCO WHSL CORP NEW COM COMMON 22160K105 693,767 15,203 2.24 274,503 14.77 0.7135
2021-05-13 2021-03-31 13F COSTCO WHSL CORP NEW COM COMMON 22160K105 678,564 130,483 23.81 239,179 15.82 0.6708
2021-02-11 2020-12-31 13F COSTCO WHSL CORP NEW COM COMMON 22160K105 548,081 20,599 3.91 206,506 10.28 0.6173
2020-11-12 2020-09-30 13F COSTCO WHSL CORP NEW COM COMMON 22160K105 527,482 18,187 3.57 187,257 21.26 0.6416
2020-10-22 2020-06-30 13F/A-1 COSTCO WHSL CORP NEW COM COMMON 22160K105 509,295 15,688 3.18 154,423 9.72 0.5817
2020-08-14 2020-06-30 13F COSTCO WHSL CORP NEW COM COMMON 22160K105 462,254 -31,353 136,448 270,408.9354
2020-05-14 2020-03-31 13F COSTCO WHSL CORP NEW COM COMMON 22160K105 493,607 17,744 3.73 140,742 0.63 0.6428
2020-02-14 2019-12-31 13F COSTCO WHSL CORP NEW COM COMMON 22160K105 475,863 7,767 1.66 139,866 3.71 0.5021
2019-11-14 2019-09-30 13F COSTCO WHSL CORP Common 22160K105 468,096 -6,385 -1.35 134,863 7.56 0.5312
2019-08-14 2019-06-30 13F COSTCO WHSL CORP COMMON 22160K105 474,481 97,461 25.85 125,386 37.35 0.4875
2019-05-14 2019-03-31 13F COSTCO WHOLESALE COMMON 22160K105 377,020 12,986 3.57 91,288 23.10 0.5338
2019-02-14 2018-12-31 13F Costco Wholesale COMMON 22160K105 364,034 28,194 8.40 74,157 -5.90 0.5034
2018-11-13 2018-09-30 13F Costco Wholesale COMMON 22160K105 335,840 -14,692 -4.19 78,805 7.58 0.4938
2018-08-13 2018-06-30 13F COSTCO WHSL CORP COMMON 22160K105 350,532 15,671 4.68 73,254 16.10 0.4972
2018-05-14 2018-03-31 13F COSTCO WHSL CORP COMMON 22160K105 334,861 -473 -0.14 63,098 1.10 0.4443
2018-02-09 2017-12-31 13F COSTCO WHSL CORP COMMON 22160K105 335,334 28,864 9.42 62,412 23.96 0.4421
2017-11-14 2017-09-30 13F COSTCO WHSL CORP COMMON 22160K105 306,470 15,039 5.16 50,350 8.03 0.3798
2017-08-14 2017-06-30 13F COSTCO WHSL CORP COMMON 22160K105 291,431 7,586 2.67 46,609 -2.08 0.3652
2017-06-19 2017-03-31 13F/A-1 COSTCO WHSL CORP COMMON 22160K105 283,845 4,242 1.52 47,598 6.32 0.3849
2017-05-09 2017-03-31 13F COSTCO WHSL CORP COMMON 22160K105 283,845 47,598
2017-02-10 2016-12-31 13F COSTCO WHSL CORP COMMON 22160K105 279,603 30,440 12.22 44,767 17.81 0.3887
2016-11-10 2016-09-30 13F COSTCO WHSL CORP COMMON 22160K105 249,163 4,196 1.71 38,000 -4.15 0.3404
2016-08-11 2016-06-30 13F COSTCO WHSL CORP COMMON 22160K105 244,967 3,954 1.64 39,646 4.39 0.3636
2016-05-12 2016-03-31 13F COSTCO WHSL CORP COMMON 22160K105 241,013 5,749 2.44 37,979 -0.04 0.3634
2016-02-11 2015-12-31 13F COSTCO WHSL CORP COMMON 22160K105 235,264 19,520 9.05 37,995 21.82 0.3800
2015-11-12 2015-09-30 13F COSTCO WHSL CORP COMMON 22160K105 215,744 39,350 22.31 31,190 30.92 0.3316
2015-08-14 2015-06-30 13F COSTCO WHSL CORP COMMON 22160K105 176,394 176,394 23,824 0.2344
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.