The city issued the big one on Friday. On October 16, Chicago approved the interior buildout permit for 500 N. Michigan Ave., the 24-story office tower at the corner of Illinois Street, and its reported value is $71.65 million.
The permit's own words lay out the job: an "interior buildout to existing 24-story mixed-use, office building to convert into multi-family residential building with 320 residential units," including "new rooftop amenity space." The retail at street level stays out of the scope.
It's the go-ahead for the main work on what JLL, which arranged the project's financing, calls "the largest office-to-residential conversion project currently underway in Chicago."
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Demolition first, then the buildout
Crews have been inside for months. The city issued an interior demolition permit for the building on May 4, reported at $2.75 million, covering non-load-bearing partitions, slab openings and old mechanical equipment. A hoist foundation and tie-in permit came even earlier, in February.
Friday's permit is the next step. Permit values are estimates filed with the city, not contract amounts, and this one covers the residential buildout. The whole project is a $162 million job, Urbanize Chicago reported when it broke ground this summer.
A 1968 office tower, bought for $5 million
The tower went up in 1968 and stands 304 feet tall on the Magnificent Mile. Most of its office space sat empty, Urbanize reported in April.
Commonwealth Development Partners, a Connecticut developer, bought it off-market in August 2025 with Triangle Capital Group for $5 million, according to JLL. In September JLL announced $113 million in financing: a $71.5 million construction loan and $41.8 million in joint venture equity.
The plan calls for studios, one- and two-bedroom apartments, with 64 of the 320 units affordable. A new 25th floor goes on top with indoor and outdoor amenity space, adding 17 feet to the building, Urbanize reported. Retail keeps the ground floors.
"We're delivering 320 units of much needed new housing," Matthew Faris of Commonwealth said in the JLL announcement.
Mayor Brandon Johnson put it this way in July: projects like this show "how we can create more housing by reimagining existing buildings," as quoted by Urbanize.
Where the reports differ
The details have shifted as the plan moved along. In April, Urbanize described apartments on floors 6 through 23, with offices kept on floors 3 through 5. By July its groundbreaking story put the apartments on floors 3 through 23. Completion targets differ too: late 2027 in Urbanize's July report, March 2028 in JLL's September announcement. The permit itself sets the count at 320 units and doesn't give a date.
Chicago's conversion pipeline
Downtown Chicago has been turning offices into homes for a while now, and the pipeline keeps growing. Nationally, conversions in the pipeline reached 90,300 apartments at the start of 2026, up 28% from a year earlier, Construction Dive reported from RentCafe figures. Chicago ranked third with 4,360 units, behind New York and Washington, D.C.
Over in the Loop, the city's LaSalle Street Reimagined program is backing six conversions that would add 1,765 mixed-income homes. The first one is finished: the Bellwether, a 121-year-old building now holding 117 apartments, 41 of them affordable, Construction Dive reported on October 1.
500 N. Michigan is a private project on the Mag Mile, not part of the LaSalle program, and at 320 units it's nearly three times the size of the Bellwether. With the buildout permit issued, the work inside moves from tearing out offices to building apartments, with the new top floor still to come.
How we count
Permits come from the City of Chicago's building permit records for 500 N. Michigan Ave., issued February through October 2026. Values are the valuations reported on the permits, not contract amounts. Company names and project details come from the news coverage linked here.
See all of Chicago's latest permit numbers, updated weekly.
Sources
- Urbanize Chicago, "Office to residential conversion at 500 N. Michigan breaks ground" (July 31, 2026): chicago.urbanize.city
- Urbanize Chicago, "Interior demo permit issued for residential conversion at 500 N. Michigan" (April 8, 2026): chicago.urbanize.city
- JLL, financing announcement for the 500 N. Michigan conversion (Sept. 21, 2026): jll.com
- Construction Dive, office-to-apartment conversion pipeline, RentCafe data (April 1, 2026): constructiondive.com
- Construction Dive, "With its first office-to-housing project done, Chicago advances 'next chapter' for its downtown" (Oct. 1, 2026): constructiondive.com
- City of Chicago building permits 101077128, 101073249 and 101082340.
- Photo: Alanscottwalker, "500 N Michigan" (2014), CC BY-SA 4.0, via Wikimedia Commons: commons.wikimedia.org
More from Morningline Research
More numbers: Chicago, IL building permit activity, updated weekly.
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