Most listings are in the $30's per square foot per year. The Center City submarket is going through a a rise in rates. In the last 3 months, the median rate went up $1 per sqft per year. That's a 2% increase in rent.
Compared to the rest of the Philadelphia market, the Center City submarket has more expensive rates, and you'll need to make a great offer to be in this hot submarket.
In the last 90 days, 122 listings have been made available, so you'll want to check back regularly for new listings. About 5% of the listings in the Center City are subleases, so you will probably need to consider the implications of signing a direct lease with the building. 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 4,950 sqft, there are still 0 listings below 2,000 sqft. Most properties in this region are close to 20 stories. Most buildings in this area were built in 1930 and are Class A.