Like other tech behemoths, Facebook is looking toward a larger future in the Big Apple with a play for the transformation of an office tower next to Madison Square Park.

The social media network is now negotiating to lease the One Madison Ave. redevelopment being planned by SL Green Realty Corp., sources say.

Back in June, I wrote that SL Green wanted to add a tower to the top of the current 1.127-million-square-foot low-slung granite building.

The 1909-era structure is leased by Credit Suisse, which is moving out. The building sits on nearly the entire block between Madison and Park Avenue South, from East 23rd to East 24th streets.

Its northwest corner hosts the New York Edition hotel in the imposing 41-story landmarked clock tower.

Earlier in December, SL Green revealed a rendering by Kohn Pedersen Fox that restacks the current building, removes several floors and adds a new 18-story tower — providing lots of setbacks, terraces and green spaces overlooking the park.

According to a spokesman, Facebook now occupies 758,000 square feet at 770 Broadway and another 266,000 square feet at 225 Park Ave. South.

In October, the Real Deal reported Facebook was in talks to lease all of 63 Madison Ave. at East 28th Street with 870,000 square feet. A long-term lease is ending there and most tenants are on co-terminating subleases.

According to the Real Deal, the Facebook negotiations caused that building to lose tenants, including the FOJP Service Corp., which is moving to 111 W. 33rd St., as I wrote in November.

But sources say those discussions with Facebook may be kaput as it turns to the upcoming reinvention of One Madison. Of course, Facebook could be negotiating with both buildings if, like other tech giants, it’s dramatically ramping up its own expansion plans over the next five years.

Indeed, 63 Madison, owned by George Comfort & Sons, Loeb Partners Realty and Jamestown, is negotiating with “several innovation/tech companies,” a source said.

As for the upcoming One Madison, on a conference call in June, SL Green Chief Executive Marc Holliday said, “This is the next great building to create value.”

Explaining the project would take several years, he said they would make sure “we have the right tenants and they pay the right rent.”

Certainly, Facebook fits that description and can foot the bill.

The companies declined to comment or couldn’t be reached.

The worldwide financial firm Macquarie, now situated at 125 W. 55th St., is weighing options for a new office of more than 200,000 square feet.

The company’s search is being led by the Savills Studley team of Mitch Steir, David Goldstein and Matthew Barlow.

The firm had been negotiating to lease space at 550 Madison Ave. — the vacant former Sony Building — but has now turned to Solow’s 9 W. 57th St., industry insiders say.

Represented by JLL, that swooping 49-story structure enjoys sweeping Central Park views and high rents in all 1.44 million square feet. Its most recent deal was pegged at $180 per square foot by CoStar.

One tenant, KKR, will be leaving next year for 343,000 square feet that it’s buying on the top floors of 30 Hudson Yards. That’s the one with the observation deck where KKR will be able to hold special events.

“Like other large-scale commercial tenants, Macquarie regularly evaluates its real estate leasing requirements. This process may involve discussions with real estate vendors, brokers and other market participants from time to time,” a spokesman emailed.

Stay tuned.