Shares of Cal-Maine Foods, the largest U.S. egg producer, fell in after-hours trading Tuesday after the company acknowledged it is being investigated by the antitrust division of the U.S. Department of Justice.

Maine Foods on Tuesday said it was cooperating with an investigation by the U.S. Justice Department regarding high price of eggs and whether producers have conspired to raise rates. The U.S. egg producer got a civil investigative demand from the authority last month,

Cal-Maine Foods is cooperating with a U.S. Department of Justice investigation into high egg prices and if producers have conspired to raise them.