Vornado filed a new building application on Oct. 3, 2025, describing the construction of the commercial high-rise at 340 Park Ave., the DOB umbrella address for the assemblage that includes 350 Park. 

The filing lists total building floor area of 2,077,720 sq ft and enrolls the project in the agency’s Major Projects Development Program. DOB records identify Michael F. Ritchie of AAI Architects P.C., associated with Adamson Associates, as architect of record. The filings do not yet list a general contractor.

The project has now completed the city’s Uniform Land Use Review Procedure, securing Midtown Special District approvals that allow transfer of development rights from landmarked properties and grant a public concourse bonus and qualifying site waivers, according to city planning records. The action was classified as a Type I review under the City Environmental Quality Review process, a designation applied to projects presumed to have the potential for significant environmental impacts.

2M-Sq-Ft Program, 82-Month Buildout

Environmental review documents provide a detailed picture of the tower’s scale and execution profile. The CEQR determination describes an office building rising about 1,600 ft and containing roughly 1.57 million sq ft of office and trading-floor space, 22,604 sq ft of retail, approximately 303,694 sq ft of mechanical space and 156,220 sq ft below grade for parking and building systems. The assessment anticipates an approximately 82-month construction period.

The unusually large mechanical allocation reflects the power and cooling demands of high-density trading operations and the shift to fully electric building systems, both of which increase equipment floor area compared with traditional fossil-fuel-based HVAC plants.

The 1,600-ft figure reflects the architectural mass studied for environmental impacts. By contrast, the DOB filing lists a high-rise determination of 1,112.43 ft measured from the highest occupied floor to the lowest fire department vehicular access for building code purposes.

Approvals confirm the project will incorporate a 12,500-sq-ft public concourse and transfer development rights from landmarked properties, including St. Patrick’s Cathedral and St. Bartholomew’s Church, to achieve its allowable floor area.

As part of the environmental determinations, the site carries a new (E) designation requiring soil, groundwater and vapor testing before construction and mandating that HVAC and hot water systems be powered by electricity rather than on-site combustion. The determination also requires a Construction Protection Plan to safeguard adjacent historic properties and a restrictive declaration incorporating Department of Environmental Protection pollution controls, including particulate matter emission limits and on-site dust management during construction.

In its Feb. 9 Securities and Exchange Form 8-K filing, Vornado described the project as a 1.85-million-sq-ft office tower anchored by Citadel. The larger gross floor area reflected in CEQR and DOB filings likely represents total construction floor area, while the SEC disclosure appears to reflect rentable or zoning floor area used for investor reporting. Vornado did not immediately respond to a request to reconcile the figures.

Under the joint venture structure outlined in the Feb. 9 filing, Vornado and the Rudin family have until July 2026 to determine whether to retain a minority stake or exercise a $1.2-billion put option tied to the assembled 350 Park site, which also includes 39 E. 51st St. and 40 E. 52nd St.

Separately, Vornado is advancing redevelopment of 623 Fifth Ave., a 36-story, 383,000-sq-ft office condominium it acquired Sept. 4, 2025, for $218 million and plans to reposition for 2027 delivery, according to the same filing.

Taken together, the filings show one of Midtown Manhattan’s largest proposed office towers advancing through technical review with a multi-year construction timeline, substantial mechanical capacity, deep below-grade work and defined environmental compliance requirements shaping execution.