Company: COST
Filing Date: 2025-06-27
Form Type: 11-K
Source: 0000909832-25-000038
Chunk: 9

Company: COSTCO WHOLESALE CORP /NEW
Filing Date: 2025-06-27
Form: 11-K
Chunk 9
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ivable from participants, which are segregated from Plan investments and measured at their unpaid principal balance plus any accrued but unpaid interest. Delinquent notes receivable are reclassified as distributions based upon the terms of the Plan document.

(e)

#### Distribution of Benefits
Distributions of benefits are recorded when paid.

(f) Subsequent Events

The Plan monitors significant events occurring after the statement of net assets available for benefits date and prior to the issuance of the financial statements to determine the impacts, if any, on the financial statements to be issued. The Plan has evaluated subsequent events through the date which the financial statements are issued.

(3)

#### Fully Benefit-Responsive Investment Contract
The CPP is invested in synthetic guaranteed investment contracts, which consist of a portfolio of underlying assets owned by the Plan and wrap contracts issued by an insurance company and a financial institution. The issuers of the wrap contracts provide for unscheduled withdrawals from the contracts at contract value, regardless of the value of the underlying assets, in order to fund routine withdrawals.

(4)

#### Fair Value Measurement
U.S. GAAP defines fair value as the price that would be received to sell an asset or paid to transfer a liability in an orderly transaction between market participants at the measurement date. Fair value is estimated by applying a fair value hierarchy, which requires maximizing the use of observable inputs. The three levels of inputs are:

Level 1: Quoted market prices in active markets for identical assets or liabilities.

Level 2: Observable market-based inputs or unobservable inputs that are corroborated by market data.

Level 3: Significant unobservable inputs that are not corroborated by market data.

The asset or liability's fair value measurement level within the fair value hierarchy is based on the lowest level of any input that is significant to the fair value measurement. Valuation techniques maximize the use of relevant observable inputs and minimize the use of unobservable inputs. Valuation techniques utilized during

<div align='center'>7</div>

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

December 31, 2024 and 2023</div>

the reporting period were not changed from previous practice. The following is a description of the valuation methodologies used for assets measured at fair value.

Common stock, underlying securities in separately managed accounts, and registered investment company funds : These investments are deemed to be actively traded and are valued at the closing price reported in the active market in which the individual securities are traded. These assets are valued using Level