Hedge-fund manager Bill Ackman is among a group of investors who agreed to pay more than $90 million for a duplex penthouse at Manhattan’s One57 condominium tower, a person with knowledge of the deal said.

Upon its completion in 2014, the purchase would be one of two at the West 57th Street property that would top the highest price paid for a single Manhattan residence. Another penthouse at One57, under construction by Extell Development Co., is also under contract to be sold for more than $90 million.

Ackman, 47, the founder of Pershing Square Capital Management LP, bought the unit with others as a personal investment and doesn’t intend to live there, the person said.

The apartment, spanning the 75th and 76th floors of the 90- story skyscraper, was last listed for sale at $115 million, according to documents filed at the office of New York State Attorney General Eric Schneiderman, which reviews details of condo plans. The 13,500-square-foot (1,300-square-meter) unit, known as the “winter garden duplex,” was originally offered at $98.5 million. Extell increased the price after the penthouse on the 89th and 90th floors sold for more than $90 million.

The winter garden duplex includes room for either a 2,500- square-foot, glass-enclosed garden or a swimming pool, Extell President Gary Barnett said in an interview last year, after sales at the tower reached $1 billion.

A message left with Barnett’s assistant, Hepzi Schechter, seeking comment on the purchase wasn’t immediately returned. Ackman said he couldn’t comment. His involvement was reported yesterday on the website of the Wall Street Journal.

Buyers at One57 have been putting in deposits based on floor plans, a model apartment in the 6,000-square-foot offsite sales office and sample apartment views photographed by a camera mounted on a drone helicopter that snapped pictures at different elevations.

The current record for the most expensive residence in Manhattan was set in February 2012, when former Citigroup Inc. Chairman Sanford Weill’s full-floor penthouse at 15 Central Park West sold for $88 million. It was purchased for the daughter of Russian billionaire Dmitry Rybolovlev.