This study extends earlier empirical work to determine whether there is a breakpoint or critical level in the frequently observed relationship between firm market share and profit rate. The analysis focuses on the banking industry and uses a sample of 10,690 firms located in 2165 different local geographic markets. Though the results apply directly only to banking, the similarity of findings on various other industrial organization topics in banking and the industrial sector suggests that the results of this study will be broadly relevant to the industrial sector.
The main findings of the study are that (1) in general, firm market share is directly related to profitability; (2) the firm market share variable remains positive and significant when controlling for market concentration either with concentration as a separate independent variable or by conducting tests with subsamples of firms that are in markets with similar concentration ratios; and (3) while there is no sharp breakpoint in the market share-profitability relationship, the results indicate that profit rates of firms increase at a decreasing rate up to a share of about 55 percent. Since numerous studies have found that economies of scale are not particularly important in banking, it appears that the observed relationship is not due to greater efficiency with larger shares.
The views expressed herein are the authors' and do not necessarily reflect the views of the Board or its staff. We extend thanks to Lynn Flynn for excellent research assistance and Rhonda Underwood for fine typing.