Magnificent Mile's 320-Unit Office Conversion Gets $71.65M Permit

The City of Chicago issued a $71.65 million renovation permit on October 16 for 500 North Michigan Avenue, the Magnificent Mile office tower Commonwealth Development Partners is converting into 320 apartments, 64 of them affordable. Permit 101082340 covers the interior buildout of the existing office building into multifamily residential space. Skender Construction LLC is listed as general contractor, and the owner of record is 500 NMA Owner LLC.

Why it matters

This is one of the largest active office-to-residential conversions in downtown Chicago, and the fresh permit is a concrete marker of how far the work has advanced. The $71.65 million figure is the applicant-stated cost of this construction phase, not a sale price or a loan balance: it happens to land close to the $71.5 million construction loan JLL reported for the project, but the two numbers measure different things and should not be conflated. For developers underwriting their own conversions, the permit gives a public data point on what a phase of this scale costs to pull through the city’s building department, separate from the project’s total capital stack.

The numbers

JLL reported in September that Commonwealth Development Partners and co-investor Triangle Capital Group lined up $113 million in total financing: a $71.5 million non-recourse construction loan from Santander Bank and $41.8 million in joint venture equity from Washington Capital Management on behalf of an institutional client. The conversion covers 253,024 rentable square feet and adds 60 garage parking spaces. Commonwealth acquired the building off-market in August 2025 for $5 million before pursuing the conversion.

What’s next

JLL reported construction began in May 2026, with completion targeted for March 2028. The conversion adds a new amenity level atop the existing structure and retains ground-floor retail. Commonwealth is pursuing Illinois’s Affordable Housing Special Assessment Program and federal historic tax credits, both still pending outcomes.

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