The typical asking rate per listing is in the $50's per square foot per year. The Greenwich region is experiencing a a rise in rates. In the last 3 months, the median rate went up $7 per sqft per year. That's a 13% increase in rent.
Compared to the rest of the Fairfield market, the Greenwich region has greater rates, and you'll need to make a great offer to be in this hot submarket.
In the last 90 days, 20 listings have been made available, which means leases most likley are leasing quickly. You'll want to be prepared to tour spaces as quick as possible. About 10% of the available space in the Greenwich 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 posted, so finding a space for a small business might be tough.
The standard measurement for office space in this area is around 2,000 sqft. Most buildings in this region are around 3 stories. Most buildings in this market were built in 1973 and are Class A.