SL Green Files 20-Story Tower at 346 Madison Avenue

SL Green Realty filed for a 20-story, 331,060-square-foot new building at 346 Madison Avenue in Midtown Manhattan, according to a Department of Buildings job filing dated October 20. It is the real estate investment trust’s fourth significant filing or transaction in seven weeks, following a SoHo sale, a raised earnings guidance and an $800 million mortgage on its 245 Park Avenue tower.

Why it matters

SL Green is Manhattan’s largest office landlord, and a ground-up new building filing is a different signal than a refinancing or a disposition. The REIT spent the first three weeks of this stretch managing its balance sheet: selling a non-core SoHo retail building, raising 2026 funds-from-operations guidance on its Q3 call, then placing fresh debt on an existing tower. A new building job at 346 Madison, a few blocks from Grand Central, points the same company toward new construction rather than only harvesting or refinancing what it already owns. The filing is a proposal under Plan Examiner review, not an approved or permitted project, and SL Green has not announced construction financing or a start date.

The numbers

The job, filed under number M01451684-I1, lists 331,060 total square feet of construction floor area across 20 proposed stories on tax lot 17 of block 1279 (BBL 1012790017, BIN 1035370), zip code 10017. Kohn Pedersen Fox is the architect of record, filed through Metropolis Group Inc. The job’s work type is listed as general construction with full demolition marked “no,” meaning any teardown of the current structure is not scoped inside this filing. As of October 26, the job sat in Plan Examiner Review, the DOB review stage that precedes permit issuance. That filing sits alongside three other SL Green moves since September 10: the $226 million SoHo sale to Natora, an FFO guidance raise on the October 23 Q3 call, and the $800 million mortgage recorded October 28 on 245 Park Avenue.

What’s next

The job must clear Plan Examiner Review and any objections before DOB issues a permit, the point at which a filing becomes an active construction project rather than a paper one. SL Green has not disclosed a construction loan, a general contractor, or a target completion date for 346 Madison Avenue. The next verifiable marker is permit issuance or a construction-financing filing tied to the same BBL.

Sources: NYC Department of Buildings DOB NOW: Build job filings. Related: SL Green’s $800 million mortgage on 245 Park Avenue, or the New York market hub.