On average, listings lease in the $10's per square foot per year. The Montgomery submarket is seeing a decline in rates. In the last 3 months, the median rate fell $1 per sqft per year. That's a 7% decline in rent.
In the last 90 days, 105 listings have come on the market, so you'll want to check back regularly for new listings. About 1% of the available space in the Montgomery 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 1,750 sqft. Most buildings in this area are around 2 floors. Most buildings in this market were built in 1979 and are Class B.