Mori Building Co., Ltd. and SL Green Launch Joint Venture for 346 Madison Avenue Office Tower in Midtown Manhattan
Tokyo-based urban developer Mori Building Co., Ltd. announced its first real estate development project in the United States — a joint venture with SL Green Realty Corp. to develop a 46-story office tower at 346 Madison Avenue in Midtown Manhattan. The partnership marks an expansion of Mori Building's international footprint into the North American market.
Mori Building holds a 49% stake in the venture. SL Green is described in the announcement as Manhattan's largest office landlord. The project is expected to be completed in 2031.
Office Tower Details and Development Scope
The planned skyscraper at 346 Madison Avenue will stand 293 meters (962 feet) tall on a 1,980 square meter (21,270 square foot) site and is expected to offer approximately 79,000 square meters (850,000 square feet) of total rentable area. The tower is designed by Kohn Pedersen Fox Associates and will include a fitness center, conference facilities, and a restaurant planned along Madison Avenue.
The site is located in the heart of Midtown Manhattan, in close proximity to Grand Central Terminal, one of New York City's primary transit hubs.
The announcement positions 346 Madison Avenue as a premium office offering built to what the companies describe as "world-class standards" with best-in-class specifications.
Relationship Built on Prior Investment
The joint venture builds on an existing relationship between the two firms. Mori Building acquired a stake in One Vanderbilt Avenue — SL Green's flagship New York asset — in 2024, establishing what both companies describe as a strong foundation of trust that preceded the 346 Madison Avenue development agreement.
SL Green held interests in 55 buildings totaling 30.8 million square feet as of March 31, 2026, according to the announcement. Its portfolio includes One Vanderbilt Avenue and One Madison Avenue, among other Manhattan properties.
For Mori Building, the venture represents an expansion of its cross-border real estate development activity. The company has previously completed large-scale projects outside Japan, including the Shanghai World Financial Center, completed in 2008, and the JAKARTA MORI TOWER, completed in 2022 in Indonesia. The 346 Madison Avenue project is framed in the announcement as an opportunity to strengthen Mori Building's portfolio and revenue base while exploring further business expansion in New York and North America.
Mori Building's Urban Development Philosophy
Mori Building describes its development approach through the corporate philosophy "Create Cities, Nurture Cities" and a concept it calls the Vertical Garden City — high-rise, mixed-use urban centers integrating business, education, leisure, and residential functions. The company has applied this model in Tokyo through projects including Roppongi Hills, Azabudai Hills, and Toranomon Hills.
The 346 Madison Avenue project is intended to reflect that development approach in a New York context, according to the announcement. Mori Building said it plans to bring experience, insights, and networks gained from the project back to its development initiatives in Tokyo. The company said it intends to continue pursuing urban development projects spanning development, investment, and consulting across borders.
No transaction price or financing terms for the joint venture were disclosed in the announcement.
Sources
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