Utilize the input text as a context reference, choose the right relationship between AmEx and American Express from the options. Options: product/material produced, manufacturer, distributed by, industry, position held, original broadcaster, owned by, founded by, distribution format, headquarters location, stock exchange, currency, parent organization, chief executive officer, director/manager, owner of, operator, member of, employer, chairperson, platform, subsidiary, legal form, publisher, developer, brand, business division, location of formation, creator.

American Express Co. on Thursday said Sam’s Club, the warehouse-club retailer owned by Wal-Mart Stores Inc., would accept AmEx cards starting Oct. 1.

Answer: operator