The U.S. Department of Justice has started seeking sworn statements from competitors and customers to prepare a possible court challenge to Whirlpool Corp.'s proposed $1.79 billion acquisition of Maytag Corp., The Wall Street Journal reported Monday. Shares of both companies slumped on the report.

Combining Whirlpool (WHR) and Maytag (MYG) would create a market giant producing half of the nation's dishwashers and more than 70 percent of its clothes washers and dryers.

The department's antitrust division is reviewing the proposed deal, which received the approval of Maytag's shareholders in December. Senior officials at the Justice Department have not yet decided whether to bring a case and the deal still could be cleared, the newspaper said. It cited unidentified people close to the case.

Agency spokeswoman Gina Talamona on Monday declined to comment on the story to The Associated Press, other than to say the review is still under way. Steven Duthie and John Daggett, spokesmen for Whirlpool and Maytag, respectively, also declined to comment on Monday to the AP.

Maytag shares lost 53 cents, or 3.3 percent, to $15.68 in morning trading on the New York Stock Exchange after losing 3.1 percent of their value on Friday. That is well below the $21 in cash-and-stock price that Whirlpool said last summer it would pay for the Newton, Iowa-based appliance maker. Whirlpool shares fell $1.58, or 1.8 percent, to $85.70 in the NYSE.

Under long-standing federal guidelines, a rise in market concentration such as the Whirlpool-Maytag deal would create usually would draw a court challenge. But Thomas Barnett, the Justice Department's antitrust chief, has not yet decided the matter, the newspaper said it was told.

Benton Harbor-based Whirlpool outbid two other suitors for Maytag, including a friendly takeover proposal by Qingdao Haier Co. Ltd., China's largest appliance maker.

Whirlpool and Maytag agreed to delay closing the deal until Feb. 27 to give the Justice Department time to complete its investigation.

The contract requires Whirlpool to pay Maytag a $120 million "reverse-breakup fee" should the deal unravel.