Justice Department Investigating Visa Over Debit-Card Practices

New civil antitrust probe follows recent government challenge to Visa’s proposed acquisition of fintech company

The Justice Department is investigating whether Visa Inc. V -4.65% is engaging in anticompetitive practices in the debit-card market, according to people familiar with the matter.

The department’s antitrust division has been gathering information and asking whether Visa, the largest U.S. card network, has limited merchants’ ability to route debit-card transactions over card networks that are often less expensive, the people said. Many of the department’s questions have focused on online debit-card transactions, but investigators have asked about in-store issues as well, the people said.

The probe highlights the important role of the so-called network fees that are invisible to consumers, lucrative for card companies, but a weight on merchants, who often pass on the fees in the form of higher prices to customers.

It comes as Justice Department antitrust enforcers across administrations have placed an emphasis on scrutinizing digital-marketplace activities, including in the financial sector, and on investigating the business practices of dominant firms.

In the new probe, the department is considering whether Visa’s practices are allowing it to maintain a dominant market share unlawfully, the people said.