The four companies that produce the overwhelming majority of the U.S.’s frozen potato products conspired to fix prices in recent years, according to a series of newly filed lawsuits.

Five antitrust suits, the Washington Post reports, were filed in an Illinois federal court in recent days against Lamb Weston, J.R. Simplot, McCain Foods and Cavendish Farms. Combined, those companies control more than 95% of the market for french fries and other frozen potato products.