The Security Building is an 11-floor high-rise within the Spring Street Financial District in Downtown Los Angeles, California. It has been converted to the residential Lofts at the Security Building. It was the former headquarters office building of Security First National Bank, completed in 1906. The building was the tallest building in the city for four years when completed. Landmark The Security Building is a Los Angeles Historic-Cultural Monument, and is a Historic district contributing property to the Spring Street Financial District, listed on the National Register of Historic Places.