Data from SEC EDGARUpdated 11/5/26, 9:45 AM PT

Form 4

Wilderotter Mary Agnes

Director

Filed: 10/26/26
Trade dates: 10/22/26
Period of report: 10/22/26
10b5-1 box: Not checked
Accession number: 0000909832-26-000123

Table I: shares of stock

Line	Security	Trade date	Shares	Price	Value	Owned after	Ownership	Notes
GrantedLine 1 · code A	Common Stock	10/22/26	266Acquired	$0	— No price on filing	8,526.936	Direct	F1, F2, F3
HoldsLine 2Indirect · By GRAT-1	Common Stock	—	—	—	—	4,696	Indirect: By GRAT-1	F3

Footnotes

F1
Grant of Restricted Stock Units. Vests one-third on October 22, 2027, and one-third on October 22 for the following two years.
F2
Not applicable. Grant of Restricted Stock Units.
F3
On July 21, 2026, 5,056 shares of Costco common stock were distributed to the reporting person in payment of an annuity from a grantor retained annuity trust (GRAT-1) of which she is the sole grantor, trustee and annuity beneficiary.