525 Market Street, once known as First Market Tower,  is an office skyscraper at the southwest corner of First- and Market Streets in the financial district of San Francisco, California. The , 39 floor tower was the second largest office building by square footage in the city (after 555 California Street) when completed in 1973.
In the heart of San Francisco's financial district stands 525 Market Street, formerly known as First Market Tower. Completed in 1973, this 39-story building held the top spot for the largest office space in the city until 555 California Street surpassed it.