In a unit under construction at 1701 Market St., a window offers a direct view of City Hall. Alterra's past conversions in Philly include former offices at 1616 Walnut St. and 1515 Chestnut.

The finding is part of the Center City District’s latest housing report, which focuses on a section of Philadelphia the nonprofit refers to as “Greater Center City.” The area — home to nearly 190,000 ...