A lawsuit filed by the Federal Trade Commission alleges that food and beverage maker PepsiCo engaged in illegal price discrimination by giving unfair price advantages to one big-box retailer.

The Robinson-Patman Act was passed in 1936, but the federal government stopped enforcing it during the deregulation of the 1980s. The FTC resumed its enforcement in December when it sued Southern Glazer’s, the largest U.S. distributor of wine and spirits.

Outgoing agency Chair Lina Khan has filed a raft of measures during her last week in office.

The U.S. Federal Trade Commission sued PepsiCo on Friday for offering preferential pricing to a large retailer, whom a source familiar with the matter confirmed was Walmart. The practices fed high consumer prices by placing at a disadvantage other retailers,

The Federal Trade Commission is suing Pepsi, alleging it has rigged competition by offering unfair pricing deals to a big retailer at the expense of smaller rivals, resulting in higher costs for shoppers.

According to the FTC’s complaint, Pepsi has been providing unfair pricing advantages to one of its largest customers—a major big box retailer—while raising prices for competing retailers and customers. Reuters reports that the retailer is none other than Walmart Inc. WMT , citing a source familiar with the discussions.