The typical asking rate per listing is in the $30's per square foot per year. The South Loop region is going through a an increase in rates. In the last 3 months, the median rate rose $3 per sqft per year. That's a 9% rise in rent.
Compared to the rest of the Chicagoland market, the South Loop region has higher rates, and you'll have to negotiate above asking rent to be in this hot submarket.
In the last 90 days, 22 listings have been made available, which means spaces most likley are leasing quickly. You'll want to be prepared to make an offer immediately. There aren't many listings below 2,000 square feet on the market, so finding a space for a small business might be tough.
Even though the median size is 3,350 sqft, there are still 0 new listings below 2,000 sqft. Most buildings in this region are close to 4 stories. Most buildings in this market were built in 1920 and are Class B.