Qwest Corporation is a Regional Bell Operating Company owned by Lumen Technologies. It was formerly named U S WEST Communications, Inc. from 1991 to 2000. It was also named Mountain States Telephone and Telegraph Company–later Mountain Bell from 1911 to 1991. In the early 2010s the Mountain Bell name was resurrected by CenturyLink, Inc. In other words, Mountain Bell Telephone Company still exists but the MB corporate name is no longer used from 1991 and afterwards. Mountain Bell now does business as the Lumen Technologies. It includes the former operations of Malheur Bell, Northwestern Bell and Pacific Northwest Bell as well. The NWBT and PNB companies still exist but no longer use the names for marketing or as corporate identities. Wikipedia