For nearly two decades banks in the United States have consolidated in record numbers—in terms of both frequency and the size of the merging institutions. Rhoades (1996) hypothesizes that the main motivations were increased potential for geographic expansion created by changes in state laws...

Over the past several years, substantial research effort has gone into measuring the efficiency of financial institutions. Many studies have found that inefficiencies are quite large, on the order of 20% or more of total banking industry costs and about half of the industry's potential profits....

We investigate the sources of recent changes in the performance of U.S. banks using concepts and techniques borrowed from the cross-section efficiency literature. Our most striking result is that during 1991-1997, cost productivity worsened while profit productivity improved substantially,...