https://www.bleepingcomputer.com/news/security/costco-discloses-data-breach-after-finding-credit-card-skimmer/

Costco Wholesale Corporation has warned customers in notification letters sent this month that their payment card information might have been stolen while recently shopping at one of its stores.

The retail giant (also known as Costco Wholesale and Costco) is an American multinational that operates a large chain of membership-only retail stores, the fifth-largest retailer worldwide, and the tenth-largest corporation in the US by total revenue according to Fortune 500 rankings.