Fulton Market Office Tightens as Onni Reverses Apartment Plan

Onni Group is dropping its apartment plan at 357 N. Green St. and returning to a roughly 900,000 square foot office tower, as Fulton Market’s 17.8 percent office vacancy runs well below the rest of downtown Chicago.

Law firm Simpson Thacher & Bartlett signed a lease for about 94,000 square feet, two floors, at 167 N. Green St., backfilling space that third-party logistics company MoLo Solutions had previously occupied, Bisnow reported. The Real Deal reported the same lease separately. Blocks away, Onni is now pursuing a 30-story office tower at 357 N. Green St., Bisnow reported, citing Crain’s. Stream Realty Partners is handling leasing. Onni originally pitched office there in 2022, pivoted to apartments in 2024, and has now reversed course again.

Why it matters

A developer reversing its own pivot away from office is a stronger signal than any single lease. For Chicago owners weighing conversions, it suggests Fulton Market’s vacancy and rent gap over downtown may again justify ground-up office, at least in this submarket.

The numbers

Fulton Market’s office vacancy sits at 17.8 percent, the lowest of any downtown Chicago submarket, per NAI Hiffman’s Q3 2026 report. That compares with 25.5 percent for the downtown CBD overall and 22.3 percent in the West Loop. Fulton Market asking rent is just under $55 per square foot, about $16 per square foot above the downtown average. The same Bisnow piece notes Sidley Austin is the proposed anchor for Related Midwest’s planned 45-story, 1 million square foot Fulton Market tower, taking more than half the building. Related still needs construction financing.

What’s next

Watch whether Onni secures financing and breaks ground on the reversed office plan, and whether Related Midwest lines up construction debt behind Sidley Austin’s commitment. Both would confirm Fulton Market, not the broader Chicago office market, is where new office supply gets built next.