Most listings are in the $30's per square foot per year. The The Loop submarket is going through a a boost in rates. In the last 3 months, the median rate increased $2 per sqft per year. That's a 6% increase in rent.
Compared to the rest of the Chicagoland market, the The Loop region has more expensive rates, and you'll need to pay a premium to be in this hot submarket.
In the last 90 days, 200 listings have been made available, so you'll want to check back regularly for new listings. About 5% of the office spaces in the The Loop are subleases, so you will probably need to sign a longer term lease with the landlord directly. There aren't many listings below 2,000 square feet available, so finding a space for a small business might be tough.
Even though the median size is 2,890 sqft, there are still 0 leases below 2,000 sqft. Most properties in this market are close to 23 stories. Most buildings in this region were built in 1929 and are Class B.