takeovers in some industries, as corporations tried to position themselves to meet changing economic conditions. Mergers were prevalent, for example, in the oil, retail, and railroad industries, all of which were undergoing substantial change. Many airlines sought to combine after deregulation unleashed competition beginning in 1978. Deregulation and technological change helped spur a series of mergers in the telecommunications industry as well. Several companies that provide local telephone service sought to merge after the government moved to require more competition in their markets; on the East Coast, Bell Atlantic absorbed Nynex. SBC Communications joined its Southwestern Bell subsidiary with Pacific Telesis in the West and with Southern New England Group Telecommunications, and then sought to add Ameritech in the Midwest. Meanwhile, long-distance firms MCI Communications and WorldCom merged, while AT&T moved to enter the local telephone business by acquiring two cable television giants: Tele-Communications and MediaOne Group.