The 27-nation bloc’s executive arm, the European Commission, has been investigating Apple since 2020. The commission’s preliminary view is that the firm is restricting competition by preventing mobile wallet app developers from accessing the necessary hardware and software on Apple devices.

Mobile wallets rely on near-field communication (NFC), which uses a chip in the mobile device to wirelessly communicate with a merchant’s payment terminal.

The commission said Apple Pay is by far the largest NFC-based mobile wallet on the market, and the only mobile wallet solution that may access the necessary NFC input on iOS, and accused the company of refusing others access to the popular technology. The commission blamed Apple for not making it available to third-party app developers.

“Apple has built a closed ecosystem around its devices and its operating system, iOS, and Apple controls the gates to this ecosystem, setting the rules of the game for anyone who...