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 undervalued submarket.
In the last 90 days, 2 listings have come on the market, which means new availabilities are probably going fast. You'll want to be prepared to tour spaces as quick as possible. About 450% of the available space in the Northern Liberties - Fishtown are subleases, so you might be able to snag a great spot on a short term. 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 4,500 sqft, there are still 0 new availabilities below 2,000 sqft. Most properties in this market are close to 4 stories. Most buildings in this area were built in 1950 and are Class B.