Walmart owns Sam's Club and operates the Walmart retail-store chain worldwide.
Sam's Club began in 1983 in Midwest City, Oklahoma, as a membership warehouse business named after Walmart founder Sam Walton. Its model resembles other warehouse clubs: members pay for access to bulk goods, groceries, fuel, and other products at competitive prices.
Walmart itself began in 1962, when Walton opened the first Walmart store in Rogers, Arkansas. The company expanded through discount retailing, large supercenters, supply-chain investment, and international operations. It became one of the world's largest companies by revenue and remains a major publicly traded corporation by market value.
Sam's Club is often confused with Costco because both use paid memberships and warehouse-style stores. They are separate companies: Sam's Club belongs to Walmart, while Costco Wholesale operates its own independent business.