1801 California Street was previously occupied by offices for US West, and then served as the world headquarters of Qwest Communications.

[1] Four Qwest logos were installed in 2000, after the corporation moved their offices from 555 17th Street, situated two blocks away.

[3] However, Qwest removed the signs in 2004 due to increasing complaints from residents of Downtown Denver and rising energy costs, and the lights were replaced with ones of a darker blue color.

[1] In December 2011, Brookfield Office Properties acquired 1801 California Street from Public Service Enterprise Group for $215 million.

[6][7] Brookfield sold a 51% interest in the property to AFL-CIO Building Investment Trust for $286 million on March 30, 2018.