On average, listings lease in the $20's per square foot per year. The Madison submarket is seeing a an increase in rates. In the last 3 months, the median rate went up $1 per sqft per year. That's a 5% increase in rent.
In the last 90 days, 24 listings have come on the market, which means new listings most likley are leasing quickly. You'll want to be prepared to make an offer immediately. About 8% of the available space in the Madison are subleases, so you will probably have to focus your search on direct office leases. 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 3,000 sqft, there are still 0 new listings below 2,000 sqft. Most properties in this area are around 1 floors. Most buildings in this area were built in 2005 and are Class B.