<P> Although Sears ' naming rights expired in 2003 , the building continued to be called the Sears Tower for several years . In March 2009 , London - based insurance broker Willis Group Holdings agreed to lease a portion of the building , and obtained the building 's naming rights . On July 16 , 2009 , the building was officially renamed Willis Tower . On August 13 , 2012 , United Airlines announced it would move its corporate headquarters from 77 West Wacker Drive to Willis Tower . </P>
<P> Although Sears ' naming rights expired in 2003 , the building continued to be called the Sears Tower for several years . In March 2009 , London - based insurance broker Willis Group Holdings agreed to lease a portion of the building , and obtained the building 's naming rights . On July 16 , 2009 , the building was officially renamed Willis Tower . On August 13 , 2012 , United Airlines announced it would move its corporate headquarters from 77 West Wacker Drive to Willis Tower . </P>
when did the sears tower became the willis tower
when did the sears tower became the willis tower
July 16 , 2009
July 16 , 2009