Rela？？o entre concentra？？o e rentabilidade no setor bancário Brasileiro

the study of bank profitability involves two lines of discussion: (1) bank performance is important to guarantee the strength of the institution and the stability of the banking industry; and (2) a greater profitability might indicate that banks have an opportunistic behavior, associated to a concentrated market. this study is aimed at evaluating the degree of concentration of the brazilian banking industry and verifying whether there is a relationship between the level of bank profitability and the sector's degree of concentration, based on total assets, credit operations and bank deposits from january 2000 to december 2009. taking the parameters of brazilian antitrust authorities as benchmarks, we cannot find evidence of concentration in the brazilian banking industry, although it should be mentioned that the concentration indicator has increased substantially from the end of 2008 onwards. when we take the concentration parameters used in the us, we find that, by the end of the period, the indicators fall within the "moderate concentration" range. as a second aim of the paper, we test hypotheses based on the structure - performance paradigm, which assumes that less competition associated to higher concentration results in higher bank profitability. the results do not corroborate the hypotheses in any of the combined tests performed, because the parameters are either statistically insignificant or negative. expectations that higher market concentration would explain higher bank profitability, according to the structure - performance hypothesis, are not confirmed. on the contrary, we find evidence that the efficient structure hypothesis explains the profitability of the brazilian banking industry more adequately.