The typical asking rate per listing is in the $20's per square foot per year. The Portsmouth region is going through a decrease in rates. In the last 3 months, the median rate fell $7 per sqft per year. That's a 24% decline in rent.
Compared to the rest of the Greater Boston market, the Portsmouth submarket has smaller rates, so you should have no trouble finding a great deal in this depreciated region.
In the last 90 days, 17 listings have been listed, which means listings are probably going fast. You'll want to be prepared to tour spaces as quick as possible. About 35% of the listings in the Portsmouth 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 posted, so finding a space for a small business might be tough.
Even though the median size is 4,500 sqft, there are still 0 leases below 2,000 sqft. Most properties in this region are around 2 floors. Most buildings in this market were built in 1910 and are Class Class B.