The typical asking rate per listing is in the $30's per square foot per year. The Diamond Bar submarket is going through a decline in rates. In the last 3 months, the median rate decreased $1 per sqft per year. That's a 2% decline in rent.
Compared to the rest of the Metropolitan Los Angeles market, the Diamond Bar submarket has greater rates, and you'll have to negotiate above asking rent to be in this hot region.
In the last 90 days, 6 listings have been listed, which means listings might be going fast. You'll want to be prepared to tour spaces as quick as possible. 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 2,200 sqft. Most properties in this area are close to 2 stories. Most buildings in this area were built in 1988 and are Class B.