CHICAGO—Many firms looking for non-traditional office space have begun to spill out of the River North area and into alternatives like the West Loop, the Fulton River area and even the East Loop. But the office market in the city's original home for tech firms and others that want loft-style spaces has not slowed down at all.

“I have not seen any reduction in demand,” Aaron Zaretsky of Urban Innovations tells GlobeSt.com. The Chicago-based company was a River North pioneer and still owns nine buildings in the neighborhood it helped transform into a trendy office market. The company, which also owns two other office buildings in the West Loop's Greektown, recently completed a new round of leases for a group of River North tenants that totals about 65,000 square feet.

One thing that has not changed in the submarket is the desire among many tenants for very short-term leases. Back in 2008, when the bottom fell out of the market, Urban Innovations did a lot of short-term leases, some even shorter than 12 months, “just to get tenants in the door,” Zaretsky says. But since many of the local tenants are start-ups, a lot still want short-term leases of between 18 months and two years.