SL Green, Mori Team Up On NYC Office Tower Near Grand Central

An 850,000-SF NYC office tower is moving forward near Grand Central Terminal, extending SL Green Realty’s push into high-end Manhattan workplace development. Bloomberg reports that the REIT announced a partnership with Tokyo-based Mori Building Co. to develop the project at 346 Madison Ave., a site positioned just blocks from One Vanderbilt. The deal adds another chapter to the firms’ growing relationship as demand remains strongest for premium office space.

A Growing SL Green-Mori Partnership

Mori is no stranger to SL Green’s Manhattan portfolio. The Japanese developer previously acquired ownership stakes in One Vanderbilt through two separate transactions completed over the past two years. Those investments valued the Midtown skyscraper at roughly $4.7B, underscoring continued investor demand for top-tier office assets.

The latest investment deepens Mori’s exposure to New York office assets at a time when many global investors remain selective about the sector. Rather than pursuing older commodity office buildings, capital continues to target newly developed properties with modern amenities and prime transit access.

The Details

The Grand Central office development will rise 46 stories and deliver approximately 850,000 SF of rentable space. Architecture firm Kohn Pedersen Fox (KPF) designed the tower with features aimed at attracting large corporate tenants, including outdoor terraces, a tenant lounge, an auditorium, and a wellness center featuring a padel court.

SL Green assembled the site in 2025, paying $160M for two adjoining buildings that will be demolished to make way for the project, according to Bloomberg. As part of the new partnership, Mori acquired a 49% ownership stake at a gross project valuation of $175M.

Located between East 44th and East 45th streets, the tower will sit within one of Manhattan’s most competitive office corridors, benefiting from Grand Central’s transit connectivity and proximity to other premier office assets.

A Strong Midtown Manhattan Office Market

The development arrives as Manhattan leasing activity continues to recover from pandemic-era disruptions. According to Savills’ Q1 2026 market data cited by Bloomberg, leasing volume during the first quarter reached its strongest level since 2019.

That recovery has not been evenly distributed across the market. Much of the demand has flowed toward trophy properties and newly constructed buildings, reinforcing the widening gap between top-tier assets and older office inventory. SL Green has already benefited from that trend through One Vanderbilt and One Madison, both of which are fully leased to tenants across the finance and technology sectors.

The planned tower at 346 Madison follows a playbook that has worked for the company before: build premium office space near major transportation hubs and target tenants willing to pay for quality, location, and amenities.

Why It Matters

The project offers another signal that investors and developers still see opportunity in office real estate despite broader uncertainty surrounding the sector. While many office markets continue to wrestle with elevated vacancies, Manhattan’s highest-end buildings have shown resilience as employers seek workplaces that support recruitment and in-person collaboration.

For developers, the announcement underscores a key market reality: demand increasingly favors a smaller pool of elite assets. Companies looking for premium space near transportation hubs face limited supply, creating an opening for new development even as older buildings struggle to compete.

SL Green CEO Marc Holliday highlighted that imbalance in the company’s announcement, noting that demand for high-quality, well-located office space continues to exceed available inventory.

What’s Next

Attention now shifts to site preparation and leasing activity as SL Green and Mori advance the project. The firms are betting that Midtown Manhattan’s flight-to-quality trend remains intact throughout the development timeline.

Market watchers will also be looking for signs that additional institutional capital follows Mori into new office construction opportunities. If leasing momentum remains strong and trophy assets continue outperforming the broader market, 346 Madison could become another test case for whether premium office development still pencils in across New York City.