It turns out Niche Media CEO Jason Binn needs less space for his magazine empire than he originally thought, and is trying to either share or unload the more than 45,000 square feet he leased downtown.

The Post has learned Niche has a sublease listing for its entire seventh-floor space at 100 Church St. Barrett Stern of Grubb & Ellis is handling the deal.

Since the space was listed last month, more than 50 companies have looked at it, Stern said. The initial asking rent is $33 to $34 per square foot.

“In a perfect world, they would find a complementary user who would use it in part,” Stern said. “It’s such a sexy space, with walls of frosted glass panels and high-end furniture.

“Unfortunately, [Niche] will have to give up all or a portion of” it.

Added Binn: “When we took the space, it was about launching and expanding. Now, it’s about preserving what you have and enhancing what you have.”

He said he hopes to stay put and find outfits that will “fill in some holes.”

In September 2007, The Post first reported that Niche was moving downtown from smaller offices in the Union Square area.

The magazine industry has suffered along with the economy, taking the luxury segment — Niche’s niche — with it. Ad sales at the company, which let its Donald Trump magazine project expire, have plunged more than 30 percent in the past year.