The largest proposed grocery store merger in U.S. history is going to court.

On one side are supermarket chains Kroger and Albertsons, which say their planned merger will help them compete against rivals like Costco. On the other side are antitrust regulators from the Federal Trade Commission, who say the merger would eliminate competition and raise grocery prices in a time of already high food price inflation.

Starting Monday, a federal district court judge in Portland, Oregon, will consider both sides and decide whether to grant the FTC’s request for a preliminary injunction. An injunction would delay the merger while the FTC conducts an in-house case against the deal before an administrative law judge.

Kroger, based in Cincinnati, Ohio, operates 2,800 stores in 35 states, including brands like Ralphs, Smith’s and Harris Teeter. Albertsons, based in Boise, Idaho, operates 2,273 stores in 34 states, including brands like Safeway, Jewel Osco and Shaw’s. Together, the companies employ around 710,000 people.

Kroger and Albertsons — two of the largest grocery chains in the U.S. — announced in October 2022 that they planned to merge. The companies say the $24.6 billion deal would hold down prices by giving them more leverage with suppliers and allowing them to combine their store brands. They say a merger also would help them compete with big rivals like Walmart, which now controls around 22% of U.S. grocery sales. Combined, Kroger and Albertsons would control around 13%.

Antitrust regulators say the proposed merger would eliminate competition, leading to higher prices, poorer quality and lower wages and benefits for workers. In February, the FTC issued a complaint seeking to block the merger before an administrative judge at the FTC. At the same time, the FTC filed the lawsuit in federal court in Oregon seeking the preliminary injunction. The attorneys general of Arizona, California, the District of Columbia, Illinois, Maryland, Nevada, New Mexico, Oregon and Wyoming all joined the federal lawsuit.

The companies say they will not close any stores with the merger.If the merger is approved, Kroger and Albertsons have agreed to sell 579 stores in places where their stores overlap. The buyer would be C&S Wholesale Grocers, a New Hampshire-based supplier to independent supermarkets that also owns the Grand Union and Piggly Wiggly store brands. Kroger and Albertsons initially planned to divest 413 stores, but the FTC said that plan would not have allowed C&S to be a robust competitor. Kroger and Albertsons agreed to divest additional stores in April. Washington has the most stores that would be divested, with 124, followed by Colorado with 91 and California with 63.