Okla. Const. art. IX, § 8

No public service corporation, or the lessees, purchasers, or managers thereof, shall consolidate the stock, property, or franchises, of such corporation with, or lease or purchase the works or franchises of, or in any way control, any other public service corporation owning or having under its control a parallel or competing line; except by enactment of the Legislature upon the recommendation of the Corporation Commission: Provided, however, That the Legislature shall never enact any law permitting any public service corporation, the lessees, purchasers, or managers thereof when such public service corporation is organized under the laws of any other State, or of the United States, to consolidate the stock, property, or franchises, of such corporation with, or lease, or purchase, the works of, franchises of, or in any way control, any other public service corporation, organized under the laws of any other State, or of the United States, owning or having under its control in this State a parallel or competing line; nor shall any officer of such corporation act as an officer of any other corporation owning or controlling a parallel or competing line.