McDonald’s has been sued in federal court in Chicago over its AI-powered pricing tool. The proposed nationwide class action alleges the company illegally coordinates menu prices.

The lawsuit, filed Friday, says McDonald’s violated antitrust law by conspiring with franchisees to fix prices using algorithms trained on nonpublic data. Reuters first reported the case.

The complaint says the pricing engine analyses data from millions of daily transactions across nearly 14,000 restaurants. “Independent businesses must set their prices independently,” it states.

McDonald’s called the allegations speculative. “AI does not set the price of a Big Mac or any other menu item,” the company said. It says franchisees make their own pricing decisions.

The plaintiff, Illinois resident Michael Thomas, seeks to represent potentially millions of customers. Similar algorithmic price-fixing suits have targeted hotels and rentals.

The Daily Caller reported the plaintiff’s lawyer accused McDonald’s of nickel-and-diming customers. TradingView noted the suit seeks to represent millions.