Unnatural Monopolies in Local Telephone

We attempt to overcome the serious data problems of past telecommunications cost studies by focusing on local exchange carriers (LECs). With enough degrees of freedom to yield precise estimates, our global subadditivity tests show that the cost function is definitely not subadditive. The results suggest that the benefits to breaking up the monopoly outputs of existing LECs substantially outweigh the potential losses in efficiency. They also support permitting entry and increasing competition in local exchange markets. Furthermore, given the competitive nature of long distance service, it is doubtful that the predivestiture Bell System was a natural monopoly.