GateHouse Media and its publicly traded publisher New Media Investment Group is deep in talks to buy USA Today owner Gannett — a merger that would make America’s biggest newspaper chain even bigger, The Post has learned.

The two parties had been previously reported to be in talks, but it was unclear until now that the deal was for the smaller Gatehouse to buy Gannett, which is already the biggest newspaper chain in the US by circulation.

Fairport, NY-based GateHouse — which owns nearly 700 papers across 39 states, including 156 dailies like the Columbus Dispatch in Ohio — is owned by Fortress Investment Group, a hedge fund controlled by business tycoon Wesley Edens.

“There’s about a 75 percent chance it happens,” a source close to the deal said. The two sides thought they were close to a deal earlier this month, the source said.

But another source insisted there are still hurdles to be cleared. “There’s nothing imminent,” the source said.

One thorny issue that still needs to be resolved involves GateHouse/New Media’s assumption of Gannett’s costly pension liabilities, a source said.

Helping to spur the deal is that Gannett and New Media have shared institutional investors, including the top three. Private equity firm Blackrock holds a 14.64-percent stake in each company. Vanguard Group holds 11.64 percent of Gannett and 10.09 of New Media; while Dimensional Fund Advisors holds 8.23 percent of Gannett and 7.33 percent of New Media.

Gannett successfully defeated a takeover bid by hedge fund Alden Global Capital earlier this year before the Gatehouse/New Media bid developed.

Gannett declined to comment. Gannett shares jumped 12 percent in late trading, to $8.90.