Costco Wholesale Corporation
US ˙ NasdaqGS ˙ US22160K1051

SecurityCOST / Costco Wholesale Corporation
InstitutionClean Yield Group
Latest Disclosed Ownership5,172 shares
Latest Disclosed Value $ 5,153,551
Clean Yield Group reports 646.32% increase in ownership of COST / Costco Wholesale Corporation

On April 14, 2026 - Clean Yield Group filed a 13F-HR form disclosing ownership of 5,172 shares of Costco Wholesale Corporation (US:COST) valued at $5,153,536 USD as of March 31, 2026. The entity filed a previous 13F-HR on January 26, 2026 disclosing 693 shares of Costco Wholesale Corporation. This represents a change in shares of 646.32% during the quarter. The current value of the position is $4,974,585 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.

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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)
2026-04-14 2026-03-31 13F COSTCO WHOLESALE CORPORATION COM Stock 22160K105 5,172 4,479 646.32 5,154 763.15 1.4508
2026-01-26 2025-12-31 13F COSTCO WHOLESALE CORPORATION COM Stock 22160K105 693 -12 -1.70 598 -8.44 0.1659
2025-10-23 2025-09-30 13F COSTCO WHSL CORP NEW COM Stock 22160K105 705 0 0.00 653 -6.59 0.1846
2025-07-17 2025-06-30 13F COSTCO WHSL CORP NEW COM Stock 22160K105 705 -6 -0.84 698 3.87 0.2089
2025-04-14 2025-03-31 13F COSTCO WHSL CORP NEW COM Stock 22160K105 711 6 0.85 673 4.19 0.2192
2025-01-13 2024-12-31 13F COSTCO WHSL CORP NEW COM Stock 22160K105 705 249 54.61 646 59.65 0.2055
2024-10-07 2024-09-30 13F COSTCO WHSL CORP NEW COM Stock 22160K105 456 0 0.00 404 4.39 0.1281
2024-07-10 2024-06-30 13F COSTCO WHSL CORP NEW COM Stock 22160K105 456 15 3.40 388 19.81 0.1448
2024-05-29 2024-03-31 13F COSTCO WHSL CORP NEW COM Stock 22160K105 441 -60 -11.98 323 -2.12 0.1257
2024-01-24 2023-12-31 13F COSTCO WHSL CORP NEW COM Stock 22160K105 501 -64 -11.33 331 3.45 0.1393
2023-10-12 2023-09-30 13F COSTCO WHSL CORP NEW COM Stock 22160K105 565 -15 -2.59 320 2.24 0.1416
2023-07-26 2023-06-30 13F COSTCO WHSL CORP NEW COM Stock 22160K105 580 -5 -0.85 312 7.59 0.1286
2023-04-26 2023-03-31 13F COSTCO WHSL CORP NEW COM Stock 22160K105 585 -56 -8.74 291 -0.68 0.1238
2023-01-31 2022-12-31 13F COSTCO WHSL CORP NEW COM Stock 22160K105 641 -11 -1.69 293 -5.19 0.1257
2022-10-31 2022-09-30 13F COSTCO WHSL CORP NEW COM Stock 22160K105 652 13 2.03 308 0.65 0.1429
2022-07-18 2022-06-30 13F COSTCO WHSL CORP NEW COM Stock 22160K105 639 0 0.00 306 -16.85 0.1265
2022-04-25 2022-03-31 13F COSTCO WHSL CORP NEW COM Stock 22160K105 639 -89 -12.23 368 -10.90 0.1300
2022-01-24 2021-12-31 13F COSTCO WHSL CORP NEW COM Stock 22160K105 728 0 0.00 413 26.30 0.1320
2021-10-27 2021-09-30 13F COSTCO WHSL CORP NEW COM Stock 22160K105 728 -35 -4.59 327 8.28 0.1073
2021-07-26 2021-06-30 13F COSTCO WHSL CORP NEW COM Stock 22160K105 763 122 19.03 302 33.63 0.1026
2021-04-26 2021-03-31 13F COSTCO WHSL CORP NEW COM Stock 22160K105 641 -75 -10.47 226 -16.30 0.0850
2021-01-26 2020-12-31 13F COSTCO WHSL CORP NEW COM Stock 22160K105 716 48 7.19 270 13.92 0.0971
2020-10-16 2020-09-30 13F COSTCO WHSL CORP NEW COM Stock 22160K105 668 43 6.88 237 24.74 0.0961
2020-07-22 2020-06-30 13F COSTCO WHSL CORP NEW COM Stock 22160K105 625 0 0.00 190 6.74 0.0821
2020-04-20 2020-03-31 13F COSTCO WHSL CORP NEW COM Stock 22160K105 625 32 5.40 178 2.30 0.0845
2020-01-17 2019-12-31 13F COSTCO WHSL CORP NEW COM Stock 22160K105 593 -123 -17.18 174 -15.53 0.0545
2019-10-23 2019-09-30 13F COSTCO WHSL CORP NEW COM Stock 22160K105 716 0 0.00 206 8.99 0.0679
2019-07-22 2019-06-30 13F COSTCO WHSL CORP NEW COM Stock 22160K105 716 51 7.67 189 17.39 0.0683
2019-04-24 2019-03-31 13F COSTCO WHSL CORP NEW COM Stock 22160K105 665 0 0.00 161 19.26 0.0652
2019-01-23 2018-12-31 13F COSTCO WHSL CORP NEW COM Stock 22160K105 665 665 135 0.0588
2017-07-17 2017-06-30 13F COSTCO WHSL CORP NEW COM Stock 22160K105 0 -493 -100.00 0 -100.00
2017-05-03 2017-03-31 13F COSTCO WHSL CORP NEW COM Stock 22160K105 493 493 83 0.0350
2017-01-24 2016-12-31 13F COSTCO WHSL CORP NEW COM Stock 22160K105 0 -428 -100.00 0 -100.00
2016-10-28 2016-09-30 13F COSTCO WHSL CORP NEW COM Stock 22160K105 428 0 0.00 65 -2.99 0.0283
2016-07-27 2016-06-30 13F COSTCO WHSL CORP NEW COM Stock 22160K105 428 0 0.00 67 3.08 0.0288
2016-04-15 2016-03-31 13F COSTCO WHSL CORP NEW COM Stock 22160K105 428 428 0.00 65 0.0289
2015-07-31 2015-06-30 13F COSTCO WHOLESALE Stock 22160K105 0 -428 -100.00 0 -100.00
2015-04-24 2015-03-31 13F COSTCO WHOLESALE Stock 22160K105 428 428 65 0.0279
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.