The Newark Star-Ledger, whose owners are threatening to close the paper if unions don't make concessions, has put its headquarters up for sale.

Publisher Richard Vezza says the sale is aimed at saving money and the newspaper is "going to lease office space," according to the Star-Ledger. Vezza said he didn't know where the newspaper would move, assuming it continues to publish.

The paper's owners said last month that they planned to close the Star-Ledger by the end of the year if production unions don't make compromises during contract negotiations. The contracts expire in July and the unions have until Sept. 27 to make concessions.

Vezza says the sale isn't related to the negotiations and the newspaper's owners, Advance Publications, have been marketing the building quietly since last year.

The Star-Ledger has worked from its headquarters at Court and Washington streets in Newark for nearly 50 years. A "For Sale" sign will go up next week and Douglas Elliman Real Estate has been retained as a broker, according to the Star-Ledger.

Ed Shown, president of the union that prints the Star-Ledger, told the newspaper that he didn't think the sale was a bargaining move.

"It makes perfect business sense to do what they are doing with the building," he said.

A number of newspapers large and small have sold their headquarters and relocated to cut costs.

In Philadelphia, the Inquirer, Daily News and Philly.com moved editorial and business operations from 400 North Broad Street to 8th and Market streets last year. Proceeds from the sale of the iconic Broad Street building were used to pay down debt.

Elsewhere, the Miaimi Herald relocated earlier this year after selling its downtown office to a developer. Washington Post executives have also said they are considering moving operations out of the paper's downtown Washington headquarters.