Regulated industries such as the telephone industry are generally less competitive than those in the manufacturing sector, due to restricted entry and uniform rate setting. Recently, peripheral competition with AT & T has emerged in areas such as microwave transmission. Telephone companies however, have exclusive markets and interface with competition only at territorial boundaries in the form of inter‐connecting lines. AT &T is a de jure monopoly controlling approximately 85 percent of the U.S. telephone revenues; GTE, its largest competitor, has only 8 percent while independent companies cover the remaining 7 percent.