$162M Mag Mile Office Tower Conversion Confirmed by City Permit

A City of Chicago permit filed for 500 N. Michigan Ave. puts a $71.7 million figure on the renovation work already underway at one of the Magnificent Mile’s largest office-to-residential conversions. Permit 101082340, a renovation and alteration permit covering 320 units, is the municipal paper trail behind a project developer Commonwealth Development Partners and its backers put at $162 million in total cost. This is not a new filing announcing the project. Construction started in May, and the permit is the public record catching up to work already in progress.

Why it matters

Office-to-residential conversions depend on the numbers lining up between what a developer tells lenders and investors and what gets filed with the city. Here they do. The $71.7 million permit covers the renovation and alteration scope at 500 N. Michigan Ave., a fraction of the $162 million total project cost that also includes financing, soft costs and the amenity addition. For a 25-story Mag Mile tower built in 1968 and largely vacant as office space, a permit of this size issued months after ground broke confirms the work is proceeding at the scale the project’s backers have described publicly, not just on a pitch deck.

The numbers

Skender is the general contractor and GREC Architects is designing the conversion of floors three through 23, currently vacant office space, into 320 residential units, 64 of them affordable. A new 25th floor will add amenity space and roughly 17 feet to the building’s height, with additional amenity programming on floors two through five. Ground-floor retail stays in place. JLL Capital Markets arranged $113 million of the financing: a $71.5 million non-recourse construction loan from Santander Bank and $41.8 million in joint venture equity from Washington Capital Management. “We’re also proud to be delivering 320 units of much needed new housing to the city,” said Matthew Faris of Commonwealth Development Partners. Commonwealth and partner Triangle Capital Group acquired the building in August 2025.

What’s next

With construction running since May 2026 and the permit now on file, the markers to watch are completion timing, reported anywhere from late 2027 to March 2028 depending on the source, and whether the project clears the Illinois Affordable Housing Support and federal historic tax credits it is pursuing. This desk will track follow-on permits tied to the amenity floor and unit build-out as they are filed. More on development activity across the city is at Chicago.