PHILADEPHIA | 1701 Market Street conversion | 18 Floors

Alterra Property Group has acquired 1701 Market St., the soon-to-be vacated headquarters of law firm Morgan Lewis & Bockius, which the developers plan to convert from offices into 299 apartments.

The transaction, which was finalized on Thursday, culminates months of negotiations and advances the largest office-to-residential conversion in Philadelphia since the pandemic. The seller is an affiliate of Lexington Industrial Trust.

Morgan Lewis is the sole tenant in the 18-story building and will be leaving for its new custom-built headquarters at 2222 Market Street. That means the building will be fully vacant, making conversion far easier for developers.

Alterra’s apartment building will have at least 180 parking spaces in its garage, and residents will also enjoy direct access to SEPTA’s Suburban Station from within the building.

The building includes about 14,000 feet of ground-floor retail. Three spaces are currently occupied by a hair salon, an AT&T, and a TruMark Financial Credit Union. The fourth space, fronting JFK Boulevard, used to host a Corner Bakery and is currently empty. Alterra is hoping to move in a high-end restaurant or retail user.

Alterra plans to refurbish an existing rooftop terrace and add a pool.

Alterra applied for permits for a 325-unit conversion in July. But the sale was still not a done deal, and Addimando declined comment at the time.

Since then, Alterra has lowered the unit count to make room for some larger apartments. There will be no studios in the building, instead it will largely be of one- and two-bedroom apartments.

Alterra expects that construction will begin early next year after Morgan Lewis moves out and anticipates that the project will be finished by early 2025.