The Department of Justice is examining Visa's interactions with fintech companies PayPal, Square and Stripe in an antitrust probe, according to the WSJ.
Antitrust investigators are looking at the incentives Visa gave to the fintech companies and whether they caused them to send transactions over Visa's payment rails instead of other networks.
The DOJ is looking at whether Visa's incentives resulted in PayPal encouraging consumers to use Visa cards, the WSJ said.
Visa is the largest card-based payment network in the U.S. But smaller competitors have been growing, from "buy now, pay later" providers such as Klarna and Affirm to PayPal and Square's own network.