Is Board Size an Independent Corporate Governance Mechanism?

Using a comprehensive set of listed Swiss companies, our findings suggestthat the size of the board of directors is an independent control mechanism.However, in contrast to previous studies, we do not find a significant rela-tionship between board size and firm performance. This suggests that Swissfirms, on average, choose their number of board members just optimally.Cross-sectional variations in board size reflect differences in firms’ underly-ing environment, but not mistaken choices.