Company: COST
Filing Date: 2025-06-27
Form Type: 11-K
Source: 0000909832-25-000038
Chunk: 4

Company: COSTCO WHOLESALE CORP /NEW
Filing Date: 2025-06-27
Form: 11-K
Chunk 4
---
825,277 |
| Distributions to participants and other              |     |                                 |     |                             |     |      | -3,016,306 |
|                                                      |     |                                 |     | Increase in net assets      |     |      |  7,632,546 |
| Net assets available for benefits, beginning of year |     |                                 |     |                             |     |      | 33,384,846 |
| Net assets available for benefits, end of year       |     |                                 |     |                             |     | $    | 41,017,392 |

<div align='center'>See accompanying notes to financial statements.

3</div>

#### COSTCO 401(k) RETIREMENT PLAN
<div align='center'>Notes to Financial Statements

December 31, 2024 and 2023</div>

(1)

#### Plan Description
The following description of the Costco 401(k) Retirement Plan (the Plan) provides only general information. Participants should refer to the Plan document for a more complete description of the Plan. To participate in the Plan, an individual must be at least 18 years of age and an employee of Costco Wholesale Corporation (the Company or Costco) or certain subsidiaries.

The Plan is a defined contribution plan for the benefit of eligible employees, established by the Company under Section 401(a) of the Internal Revenue Code (IRC). It includes a qualified cash or deferred arrangement as described in Section 401(k). The Plan is also subject to the provisions of the Employee Retirement Income Security Act of 1974 (ERISA), as amended.

(a)

#### Employee Contributions
The Plan allows certain employees to make compensation deferral contributions after completing 90 days of service within 12-consecutive months. Eligible employees may contribute from 1% to 50% of their compensation, subject to certain limitations set by the IRC and the Plan. Eligible employees may also contribute amounts representing certain distributions from other retirement plans (rollover contributions).

All newly-eligible participants entering the Plan are automatically enrolled at a salary contribution rate of 4%. On an active participant’s employment anniversary date and each anniversary date thereafter the percentage deferred into the Plan automatically increases by one percentage point, to a maximum of 20%. Employees may opt out of automatic enrollment and increases. Contributions are subject to regulatory requirements.

(b)

#### Employer Contributions
Company contributions are invested in accordance with selections made by participants. If no selection has been made, the contribution defaults to the Retirement Trust corresponding to the participant's age