SL Green, Manhattan’s largest office landlord, is adding to its collection in the corporate-headquarters-heavy Park Avenue office corridor of New York City, an area where SL Green said the vacancy rate has fallen below 6%.
SL Green said late Wednesday it has entered into a contract to buy Park Avenue Tower, located at 65 E. 55th St. just off Park Avenue, from private equity giant Blackstone for $730 million, with the deal expected to close in the first quarter.
For Blackstone, the deal “capitalizes on the strong rebound in demand for office in Midtown Manhattan and demonstrates the momentum for recently renovated office assets in prime submarkets,” a spokesperson said in an emailed statement.
SL Green’s purchase comes as New York, led by the so-called flight-to-quality demand for top-tier office properties in corridors such as Park Avenue, has outpaced the United States in the sector’s rebound from the pandemic. The office vacancy rate in New York, the largest U.S. office market, has declined from a record high of over 14% to just over 13% even as the national average continues to inch higher, according to CoStar data.
Manhattan’s office leasing volume in the first three quarters of 2025 rose about 30%, to 30.05 million square feet, the strongest year-to-date period of demand since 2002, according to a Colliers study. Meanwhile, as employers seek modern and top-tier properties with appealing amenities to lure employees back to the workplace, Manhattan’s Class A properties in the first three quarters totaled 17.9 million square feet, the strongest in over 30 years, a Cushman & Wakefield study found.
New York office foot traffic in July also topped the pre-pandemic level, the first time any major city has closed the pre-pandemic return-to-office visit gap, a Placer.ai study has found.
“This acquisition will deliver sustainable cash flow and provide long-term value creation while further solidifying our commitment to being the leading owner of premier properties along Park Avenue at a time when demand has never been higher,” SL Green Chief Investment Officer Harrison Sitomer said in a statement. “Park Avenue Tower is strategically located and well-leased at below-market rents, offering significant upside as vacancy in the Park Avenue corridor continues to trend below 6 percent.”
SL Green’s Park Avenue portfolio includes One Vanderbilt Ave. with direct connection to Grand Central Terminal; 500 Park Ave., 450 Park Ave., 280 Park Ave., 245 Park Ave., 125 Park Ave. and 100 Park Ave., Sitomer said.
Located block-through between 55th and 56th Streets, the 36-story, 621,824-square-foot Park Avenue Tower, designed by architect Helmut Jahn and completed in 1986, features upgraded infrastructure and newly renovated interiors, SL Green said.
Included in the glow up were a reimagined plaza and high-end prebuilt office suites.
The purchase marks one of the city’s largest office deals this year. Office sales have been picking up as the supply of top-tier and well-located office properties shrinks.
Separately, SL Green said it also is buying 346 Madison Ave. and the adjacent site at 11 E. 44th Street for $160 million.
SL Green isn’t the only one shopping New York office properties.
Nearby the Park Avenue Tower, RXR recently bought 590 Madison Ave., a trophy 1 million-square-foot, 42-story Class A tower previously known as the IBM Building, for $1.08 billion in Manhattan’s largest office deal since March 2022.
Tishman Speyer this year also bought its first New York office building since 2019 while tech giant Amazon opened its wallet for a midtown office property, its first like purchase in New York since 2020. Blackstone, for its part, has bought a 46% joint-control interest in 1345 Ave. of the Americas, another corridor where office landlords said the vacancy rate is in the single digits.
Non-U.S. investors are showing strong interest in top-tier New York offices. Japan’s Mori Building has bought another 5% interest in SL Green’s 100%-leased trophy tower One Vanderbilt Ave. after first acquiring an 11% stake in November 2024.
In yet another sign of demand, about 20 blocks south of One Vanderbilt, One Madison Ave., another one of SL Green’s trophy towers, reported a leased occupancy rate of 91.2%, up from 78.1% in July, after signing a slew of leases.
For the record
Gary Phillips and Will Silverman of Eastdil Secured represented Blackstone in the transaction.