Most listings are in the $10's per square foot per year. The Northern Liberties - Fishtown submarket is experiencing a an increase in rates. In the last 3 months, the median rate went up $20 per sqft per year.
Compared to the rest of the Philadelphia market, the Northern Liberties - Fishtown region has lower rates, so you should have no trouble finding a great deal in this depreciated submarket.
In the last 90 days, 2 listings have been posted online, which means leases most likley are leasing quickly. You'll want to be prepared to tour spaces as quick as possible. About 300% of the office spaces in the Northern Liberties - Fishtown are subleases, so you might be able to sign a shorter term by taking over a previous lease. 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 4,500 sqft, there are still 0 new availabilities below 2,000 sqft. Most properties in this market are approximately 4 floors. Most buildings in this market were built in 1950 and are Class B.