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Is The “Dominant Firm” Dominant? An Empirical Analysis Of At&T’S Market Power, Simran K. Kahai, David L. Kaserman, John W. Mayo

Economics & Finance

In this article, we estimate the degree of market power held by AT&T in the interstate long-distance market in the postdivestiture period. Our approach makes use of the dominant firm/competitive fringe model to impose the structure needed both to obtain estimates of the relevant structural parameters and to translate these parameters into an estimate of AT&T's residual demand elasticity and associated Lerner index. Because of the continued presence of regulation and other considerations, however, a direct estimation of the residual demand elasticity is not feasible. Consequently, we take a more indirect approach that combines estimation of the elasticity of fringe …