There is 750,000 square feet of office space coming on the market in Novato.

The Fireman’s Fund Insurance Co. is leaving an office building in the city, making a large space available for hungry tech firms looking to expand. The firm was already trying to sublease about one third of the space, to no avail.

American Assets Trust owns the building. There is speculation that Google, or a similar firm, might take up the vacancy. There are currently about 150,000 square feet of other tenants in the building.