Starbucks Corp. now sells Square Inc.'s mobile card reader in its stores, the mobile-payments company announced Jan. 3.
The two companies have worked closely since August, but until now there wasn't a place for Square's popular card reader in Starbucks stores. Although Starbucks agreed to use Square's software and its processing services, it did not agree to use Square's card reader to handle payments.
Square already offers its card reader at many retailers. Merchants can also sign up for Square by downloading its mobile app.
In November, Starbucks began accepting Square Wallet, a software-based system for making payments with a card account that has been previously enrolled with Square.
As part of the August agreement, Starbucks invested $25 million in Square. Howard Schultz, president and CEO of Starbucks, joined Square's board.