The Justice Department filed an antitrust lawsuit against Visa on Tuesday, accusing the financial giant of unfairly stifling competition in debit cards, the latest in a string of cases aimed at deterring monopolistic behavior by big companies.

For more than a decade, the government claims in its complaint, Visa has entered into de facto exclusive agreements with merchants and banks, encouraging them to route the bulk of their transactions through Visa’s payment network. The company has maintained a monopoly in large part by imposing or threatening to impose higher fees on merchants that also use other payment networks to process debit transactions, according to the Justice Department.

The lawsuit stems from a widespread investigation dating back years. It is part of a series of efforts made by enforcers under the Biden administration to target corporate middlemen, which it says needlessly increase fees, and take aim at power wielded by companies spanning technology to agriculture. President Joe Biden in 2021 rolled out an executive order that made aggressive antitrust enforcement a pillar of his economic policy.

Visa is a very big middleman: It processed $3.8 trillion in U.S. debit transactions in the year through June, generating over $7 billion in processing fees per year, the Justice Department said. Those account for more than 60% of all such transactions.

“Visa’s unlawful conduct affects not just the price of one thing, but the price of nearly everything,” Attorney General Merrick Garland said in a statement accompanying the complaint, which was filed in the Southern District of New York.

Visa’s fees, which are largely invisible to the public, are paid by merchants and can be passed on to consumers, hitting younger and lower income Americans the hardest, Benjamin Mizer, the Justice Department’s third-ranking official, said at a press conference Tuesday.

Julie Rottenberg, Visa’s general counsel, said in a statement: “Today’s lawsuit ignores the reality that Visa is just one of many competitors in a debit space that is growing, with entrants who are thriving.”

Rottenberg added, “this lawsuit is meritless, and we will defend ourselves vigorously.”

The antitrust violations outlined in the government’s complaint encompass all debit transactions using a physical card, as well as online or app-based purchases. Suppressing alternative card networks, which connect a cardholder’s bank to the merchant’s bank when a purchase is made, has reduced competition in the market and “slowed innovation in the debit payments ecosystem,” the Justice Department said.

The government also claims that Visa has deterred other companies, such as PayPal and Square, from entering the debit card market. It says Visa has paid financial technology companies to be partners, rather than let them evolve into rivals, citing internal Visa documents.

“Visa abuses its monopoly power to thwart existing debit rivals and buy off would-be rivals at the expense of consumers, merchants, banks and the competitive process itself,” Doha Mekki, the principal deputy assistant attorney general at the Justice Department’s antitrust division, said in a statement.

The department’s concerns with Visa are long-standing. Its antitrust division in 2020 sued to block Visa’s $5.3 billion deal to acquire the financial technology firm Plaid, arguing that Visa intended to stamp out a nascent rival.

Visa and Plaid abandoned their deal two months later.

Federal antitrust regulators have scrutinized Mastercard, too, over allegations that it has illegally suppressed competing debit payment networks. Visa and Mastercard together dominate the payments industry and have fought allegations that they maintain a duopoly. Last year, the Federal Trade Commission reached an agreement with Mastercard that requires the company to share customer account information with competing networks and allow merchants to choose between rival networks.