Announced

346 Madison Avenue

New York City · Office

346 Madison Avenue is a 46-story, all-electric trophy office tower rising one block from Grand Central Terminal and across from One Vanderbilt in Midtown Manhattan, developed as a joint venture between SL Green and Japan's Mori Building — Mori's first U.S. development.

Official Website
Last verified Jul 17, 2026
5.4 yrs to delivery
5%
AnnouncedBreaking GroundConstructionOpening SoonNow Open
2031
Completion
46
Floors
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The story so far
Announced Sep 2025SL Green acquired 346 Madison ($160M) and unveiled 46-story all-electric office tower, Sept 2025; ~850K rentable sf
slgreen.com
Financing secured May 27, 2026Capital event, not a construction loan: SL Green closed sale of a 49% JV equity interest to Mori Building Co. at a $175M valuation (Mori's first US development), formalizing the project. GFA/delivery/address backfilled in same call.
slgreen.com
Expected groundbreaking 2026 est.
oftmw.com
Expected opening 2031
Milestones are dated to when they actually happened and linked to their source. This record fills in over time as TMW tracks the project.
About the project

346 Madison Avenue is a 46-story, all-electric trophy office tower rising one block from Grand Central Terminal and across from One Vanderbilt in Midtown Manhattan, developed as a joint venture between SL Green and Japan's Mori Building — Mori's first U.S. development. Designed by KPF with roughly 850,000 rentable square feet, the tower features side-core, column-free floors with 15-to-22-foot ceilings, nine terrace levels and nine loggia floors, and a two-story amenity collection including a 215-seat auditorium, a Daniel Boulud épicerie, a wellness center with a regulation padel court, and a ground-floor restaurant.

Developer & design
Architect
The New York City market 65 · Elevated supplyMidtown East 23-project pipeline · 7,801 residences and keys · peak Late ’28 Explore the market →
Journal Coverage
346 Madison Avenue has been covered in 1 article on Markets of Tomorrow.
Common questions

Frequently asked

Where is 346 Madison Avenue located?

346 Madison Avenue is located in New York City.

When will 346 Madison Avenue be built?

346 Madison Avenue is an announced development that has not yet started construction, targeting completion in 2031.

Who is developing 346 Madison Avenue?

SL Green, Mori Building is the developer behind 346 Madison Avenue.

Who designed 346 Madison Avenue?

346 Madison Avenue was designed by KPF.

How big is 346 Madison Avenue?

346 Madison Avenue rises 46 stories.