Walmart Pay aims to make checkout faster and more convenient.

(Bloomberg)—Wal-Mart Stores Inc. is expanding its mobile-payment system across the U.S., adding convenience for shoppers and giving the world’s biggest retailer new data into its customers’ shopping habits.

The Walmart Pay feature on its app—available on Apple and Android devices—can now be used at all 4,600 U.S. stores, the Bentonville, Ark.-based retailer said Wednesday. Wal-Mart, No. 4 in the Internet Retailer 2016 Top 500 Guide,  said more than 20 million people regularly use its app, which also provides discounts and helps shoppers locate items within stores.

Wal-Mart is betting that the new payment system will make the checkout process more convenient and speed checkout times, though it doesn’t have a figure on how much time it saves shoppers. The expansion also puts the retailer in direct competition with technology giants such as Apple Inc. (No. 2), Alphabet Inc. and Samsung Electronics Co., which all offer their own ways for consumers to make mobile purchases.

Shares of Wal-Mart rose 1% to $73.88 at 3:02 p.m. in New York. The stock already had gained 19% this year through Tuesday.