Costco Wholesale Corporation
MX ˙ BMV ˙ US22160K1051
SecurityMX:COST / Costco Wholesale Corporation
InstitutionFactory Mutual Insurance Co
Latest Disclosed Ownership29,200 shares
Latest Disclosed Value $ 29,095,756
Factory Mutual Insurance Co reports 3.91% increase in ownership of COST / Costco Wholesale Corporation

On May 5, 2026 - Factory Mutual Insurance Co filed a 13F-HR form disclosing ownership of 29,200 shares of Costco Wholesale Corporation (MX:COST) valued at $29,095,756 USD as of March 31, 2026. The entity filed a previous 13F-HR on January 23, 2026 disclosing 28,100 shares of Costco Wholesale Corporation. This represents a change in shares of 3.91% 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)
2026-05-05 2026-03-31 13F COSTCO WHOLESALE COM 22160K105 29,200 1,100 3.91 29,096 20.07 0.3273
2026-01-23 2025-12-31 13F COSTCO WHSL CORP COM 22160K105 28,100 -1,100 -3.77 24,232 -10.35 0.2457
2025-11-10 2025-09-30 13F COSTCO WHSL CORP COM 22160K105 29,200 0 0.00 27,028 -6.50 0.2632
2025-08-07 2025-06-30 13F COSTCO WHSL CORP COM 22160K105 29,200 0 0.00 28,906 4.67 0.3160
2025-04-17 2025-03-31 13F COSTCO WHSL CORP COM 22160K105 29,200 0 0.00 27,617 3.22 0.3204
2025-01-24 2024-12-31 13F COSTCO WHSL CORP COM 22160K105 29,200 0 0.00 26,755 3.36 0.2893
2024-10-10 2024-09-30 13F COSTCO WHSL CORP COM 22160K105 29,200 -500 -1.68 25,886 2.54 0.2677
2024-07-23 2024-06-30 13F COSTCO WHSL CORP COM 22160K105 29,700 -500 -1.66 25,245 14.10 0.2876
2024-04-12 2024-03-31 13F COSTCO WHSL CORP COM 22160K105 30,200 -1,000 -3.21 22,125 7.43 0.2541
2024-01-23 2023-12-31 13F COSTCO WHSL CORP COM 22160K105 31,200 -7,300 -18.96 20,594 -5.31 0.2558
2023-11-07 2023-09-30 13F COSTCO WHSL CORP COM 22160K105 38,500 0 0.00 21,751 4.94 0.3034
2023-07-27 2023-06-30 13F COSTCO WHSL CORP COM 22160K105 38,500 0 0.00 20,728 8.35 0.3058
2023-05-08 2023-03-31 13F COSTCO WHSL CORP COM 22160K105 38,500 -1,400 -3.51 19,129 5.02 0.2990
2023-02-02 2022-12-31 13F COSTCO WHSL CORP COM 22160K105 39,900 10,200 34.34 18,214 29.86 0.2755
2022-11-04 2022-09-30 13F COSTCO WHSL CORP COM 22160K105 29,700 0 0.00 14,026 -1.46 0.2303
2022-08-08 2022-06-30 13F COSTCO WHSL CORP COM 22160K105 29,700 0 0.00 14,234 -16.77 0.2333
2022-05-13 2022-03-31 13F COSTCO WHSL CORP COM 22160K105 29,700 0 0.00 17,102 21.15 0.2313
2022-02-10 2021-12-31 13F COSTCO WHSL CORP COM 22160K105 29,700 -7,701 -20.59 14,116 -16.01 0.2038
2021-11-12 2021-09-30 13F COSTCO WHSL CORP COM 22160K105 37,401 0 0.00 16,806 13.57 0.2099
2021-07-14 2021-06-30 13F COSTCO WHSL CORP COM 22160K105 37,401 -923 -2.41 14,798 9.54 0.1810
2021-05-10 2021-03-31 13F COSTCO WHSL CORP COM 22160K105 38,324 -976 -2.48 13,509 -8.77 0.1728
2021-02-17 2020-12-31 13F COSTCO WHSL CORP COM 22160K105 39,300 0 0.00 14,807 6.13 0.2002
2020-10-19 2020-09-30 13F COSTCO WHSL CORP COM 22160K105 39,300 0 0.00 13,952 17.08 0.2258
2020-07-13 2020-06-30 13F COSTCO WHSL CORP COM 22160K105 39,300 0 0.00 11,917 6.34 0.2044
2020-04-16 2020-03-31 13F COSTCO WHSL CORP COM 22160K105 39,300 0 0.00 11,206 -2.99 0.2128
2020-01-28 2019-12-31 13F COSTCO WHSL CORP COM 22160K105 39,300 0 0.00 11,551 2.02 0.1703
2019-10-22 2019-09-30 13F COSTCO WHSL CORP COM 22160K105 39,300 -22,400 -36.30 11,322 -30.56 0.1750
2019-07-16 2019-06-30 13F COSTCO WHSL CORP COM 22160K105 61,700 0 0.00 16,304 7.31 0.1949
2019-04-09 2019-03-31 13F COSTCO WHSL CORP COM 22160K105 61,700 -35,300 -36.39 15,194 -23.11 0.1794
2019-01-14 2018-12-31 13F COSTCO WHSL CORP COM 22160K105 97,000 -101,800 -51.21 19,760 -57.68 0.2535
2018-10-10 2018-09-30 13F COSTCO WHSL CORP COM 22160K105 198,800 0 0.00 46,694 12.39 0.4847
2018-07-19 2018-06-30 13F COSTCO WHSL CORP COM 22160K105 198,800 1,800 0.91 41,545 11.92 0.4458
2018-04-05 2018-03-31 13F COSTCO WHSL CORP COM 22160K105 197,000 0 0.00 37,120 1.24 0.4065
2018-01-16 2017-12-31 13F COSTCO WHSL CORP COM 22160K105 197,000 8,000 4.23 36,665 18.08 0.3835
2017-10-11 2017-09-30 13F COSTCO WHSL CORP COM 22160K105 189,000 13,800 7.88 31,051 10.82 0.3404
2017-07-10 2017-06-30 13F COSTCO WHSL CORP COM 22160K105 175,200 -16,300 -8.51 28,020 -12.75 0.3241
2017-04-21 2017-03-31 13F COSTCO WHSL CORP COM 22160K105 191,500 -21,500 -10.09 32,113 -5.20 0.3804
2017-01-19 2016-12-31 13F COSTCO WHSL CORP COM 22160K105 213,000 0 0.00 33,873 4.27 0.4020
2016-10-26 2016-09-30 13F COSTCO WHSL CORP COM 22160K105 213,000 0 0.00 32,485 -2.88 0.4017
2016-07-12 2016-06-30 13F COSTCO WHSL CORP COM 22160K105 213,000 40,000 23.12 33,450 22.70 0.4407
2016-04-27 2016-03-31 13F COSTCO WHSL CORP COM 22160K105 173,000 0 0.00 27,261 -2.43 0.3528
2016-01-14 2015-12-31 13F COSTCO WHSL CORP COM 22160K105 173,000 -20,000 -10.36 27,940 0.14 0.3758
2015-10-14 2015-09-30 13F COSTCO WHSL CORP COM 22160K105 193,000 0 0.00 27,902 7.04 0.3817
2015-07-21 2015-06-30 13F COSTCO WHSL CORP COM 22160K105 193,000 0 0.00 26,067 -10.84 0.3405
2015-04-13 2015-03-31 13F COSTCO WHSL CORP COM 22160K105 193,000 -14,000 -6.76 29,237 -0.36 0.3852
2015-01-12 2014-12-31 13F COSTCO WHSL CORP COM 22160K105 207,000 -46,000 -18.18 29,342 -7.46 0.3954
2014-11-04 2014-09-30 13F COSTCO WHSL CORP COM 22160K105 253,000 0 0.00 31,706 8.82 0.4385
2014-08-12 2014-06-30 13F COSTCO WHSL CORP COM 22160K105 253,000 253,000 29,135 0.3984
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.