SL Green Realty Corp. and Japan-based Mori Building Co. have formed a joint venture to develop 346 Madison Avenue, a new office tower in Manhattan’s East Midtown, in a deal that underscores continued investor confidence in premium office assets in New York City.
Under the agreement, Mori Building acquired a 49% stake in the project at a gross valuation of $175 million. SL Green will retain a 51% interest and oversee development and leasing activities.
Located one block from Grand Central Terminal and directly across from One Vanderbilt, the project will add an approximately 850,000-square-foot, 46-storey office tower to one of Manhattan’s most sought-after business districts.
The partnership marks Mori Building’s first development project in New York and brings together two companies with extensive experience delivering large-scale urban projects.
“346 Madison Avenue will set a new benchmark for innovative office development in East Midtown,” said Marc Holliday, Chairman and CEO of SL Green. “Tenant demand for the highest-quality, best-located, and most thoughtfully designed buildings far exceeds available supply.”
Designed by architecture firm Kohn Pedersen Fox (KPF), the all-electric tower is expected to target the highest sustainability and WELL certifications. The building will feature column-free floorplates, high ceilings, outdoor terraces, and a range of wellness-focused amenities.
Plans include a two-floor amenity centre with a 215-seat auditorium, a tenant lounge, a fitness centre, spa-quality locker rooms, and what developers say will be the only regulation-sized padel court inside an office building. A luxury restaurant and retail offerings are also planned for the ground floor.
Mori Building President and CEO Shingo Tsuji said the project represents an opportunity to combine the company’s expertise in large-scale urban development with SL Green’s experience shaping Manhattan’s skyline.
The venture also highlights growing cross-border investment between the United States and Japan and reflects continued demand for next-generation office space despite broader challenges facing commercial real estate markets.
As companies increasingly prioritise premium locations, employee wellness, and sustainability, developers are betting that modern, amenity-rich buildings will outperform older office stock.
SL Green, Manhattan’s largest office landlord, currently holds interests in 55 buildings comprising more than 30 million square feet. Mori Building is one of Japan’s leading urban developers and is known for landmark projects including Roppongi Hills, Toranomon Hills, and Azabudai Hills in Tokyo.
Construction of 346 Madison Avenue will further expand SL Green’s East Midtown portfolio and add another high-profile development to a district that has emerged as a focal point for office investment and urban renewal in New York City.
