Harbor Group fills famed Black Rock tower with 170K sf law firm lease

Harbor Group International’s multimillion-dollar bet on the Black Rock building has paid off.

International law firm Alston & Bird signed a 170,000-square-foot lease at HGI’s 51 West 52nd Street, also known as 51W52 and Black Rock, bringing the Midtown trophy tower to full occupancy.

The firm inked a 15-year deal for floors nine through 15 at the roughly 900,000-square-foot Class A office tower, according to an announcement from Newmark. It will relocate its New York office from 90 Park Avenue and expand its footprint by more than 30 percent. The asking rent was not disclosed.

A Newmark team including Howard Hersch, Greg Conen and Scott Klau represented the landlord. A Savills team including Brad Wolk, Matthew Barlow and David Goldstein represented Alston & Bird.

The lease marks a milestone for HGI, which acquired the 38-story property in 2021 from ViacomCBS for $760 million and has since poured about $128 million into improvements aimed at attracting top-tier tenants. The upgrades include a revamped lobby, a new amenity center dubbed Club 53 and food-and-beverage services.

“This validates our strong faith in the resilience of the New York office market, especially for the best trophy properties in the best locations,” HGI Chairman and CEO Jordan Slone said in a statement.

The deal adds another data point to Manhattan’s bifurcated office market, where trophy and Class A towers continue to attract tenants while older properties struggle with vacancies. Law firms, in particular, have been among the most active occupiers of premium office space, helping drive leasing activity across Midtown.

Law firms leased 3.74 million square feet of Manhattan office space across 115 transactions in 2025, a 17.8 percent increase year-over-year and a new annual record by more than 30 deals, according to Colliers.

The dark granite tower with tinted glass windows was designed by architect Eero Saarinen, completed in 1965 and later became a designated landmark. The 2021 sale was the first time the building had changed hands. Other tenants in the tower include law firms Orrick, Herrington & Sutcliffe and Wachtell, Lipton, Rosen & Katz, and the Kroll Bond Rating Agency.