SL Green Partners With Mori Building on 346 Madison Avenue

SL Green brought its frequent partner Mori Building in to help develop its latest office tower.

The REIT sold a 49 percent stake in the project at 346 Madison Avenue to Mori Building, which has teamed up with SL Green on One Vanderbilt and 245 Park Avenue.

The deal values the property — which will eventually give way to an 850,000-square-foot office tower — at $175 million.

“Tenant demand for the highest-quality, best-located, and most thoughtfully designed buildings far exceeds available supply,” said SL Green CEO Marc Holliday, who added that now is “the perfect time” to develop the tower.

SL Green bought 346 Madison Avenue — Brooks Brothers’ former flagship store — for $160 million last year. It will be the company’s first ground-up office development since One Vanderbilt, which opened in 2021.

Japan-based Mori bought an 11 percent stake in the 1.7 million-square-foot One Vanderbilt in 2024 in a deal that valued the skyscraper at $4.7 billion. It also bought a stake in SL Green’s 245 Park Avenue at a $2 billion valuation.

At 346 Madison, SL Green and Mori will develop an all-electric building standing 46 stories tall with column-free floorplates. It will have nine terrace floors and a two-floor amenity space that will include a 215-seat auditorium and a tenant lounge with an épicerie run by celebrity chef Daniel Boulud.