Authors: Renée B. Adams and Hamid Mehran

The subprime crisis highlights how little we know about the governance of banks. This paper addresses a long-standing gap in the literature by analyzing board governance using a sample of banking firm data that spans forty years. We examine the relationship between board structure (size and composition) and bank performance, as well as some determinants of board structure. We document that mergers and acquisitions activity influences bank board composition, and we provide new evidence that organizational structure is significantly related to bank board size. We argue that these factors may explain why banking firms with larger boards do not underperform their peers in terms of Tobin’s Q. Our findings suggest caution in applying regulations motivated by research on the governance of nonfinancial firms to banking firms. Since organizational structure is not specific to banks, our results suggest that it may be an important determinant for the boards of nonfinancial firms with complex organizational structures such as business groups.