The National Enquirer, the supermarket tabloid that once published a photo of Elvis Presley in his coffin and later backed Donald J. Trump’s presidential campaign, is for sale, the publisher said in a statement.

The Enquirer, owned by American Media Inc. and led by David J. Pecker, a longtime friend of Mr. Trump’s, is likely to have a buyer in a matter of days, according to two people with direct knowledge of the matter, who spoke on condition of anonymity to describe private negotiations.

Mr. Pecker is said to have helped Mr. Trump’s candidacy through American Media’s deal to buy a story from Karen McDougal, a Playboy model who said she had an affair with the president. The company acquired her story for $150,000 and never published it, following a practice known in the tabloid business as catch-and-kill. Federal prosecutors from the Southern District of New York gave Mr. Pecker an immunity deal in its investigation of the arrangement.

Prosecutors identified the $150,000 payment to Ms. McDougal as a political contribution made in violation of campaign finance law. Under a non-prosecution deal, American Media affirmed that it had made the payment to “influence the election.”