The Justice Department filed an antitrust lawsuit against Visa on Tuesday over allegations it illegally monopolized the debit network market.

The Justice Department said Visa uses a system of carrots and sticks to stave off any possible competitors and keep merchants. The lawsuit, filed in the U.S. District Court for the Southern District of New York, notes that more than 60% of debit transactions run on Visa’s network, which allows the company to charge more than $7 billion annually in processing fees.