according to the assumption of the agency costs of debt-equity, the banks' presence in the Board of Directors negatively effects on the company's value. Bubna and Radhakrishnan [5] showed that there are information asymmetries between the shareholders and the creditors. According to this hypothesis, the presence of banks in the board of directors reduces the information asymmetries between the firms and the creditors and consequently improves the companies' value.The existence of conflicts of interest between the shareholders and the creditors is reduced by a set of internal and external mechanisms. The board of directors and ownership structure are two alternative mechanisms of governance and control. Besides these two internal governance mechanisms, the presence of banks in the board of directors and ownership structure are also two governance mechanisms since this presence is associated with a reduction of the agency costs due to the conflicts of interest between the shareholders and the creditors.The practice of the banks' participation in the firms' capital depends on the country considered. Actually, in France, for example, banks are under no obligation to participate in the firms' capital. However, the American legislation and more particularly the Glass-Steagall Act (1933) prevents banks from participating in the firms' capital. Recently, the American legislation, through the Gramm-Leach-Bliley Act, has given commercial banks the opportunities to participate in the capital of firms. Besides, Germany, which encourages the banks' participation in the companies' capital, introduced some restrictions which were discussed in the Bundestag (1977). A very recent study has revealed that the Monopoly Commission limited the banks' participation to the amount of 5% of the companies' capital. The banking regulations in Keywords: Bankers on board; Banks as shareholders; Firm's Performance; Anglo-Saxon Introduction Nowadays, the corporate finance researches attach great importance to the role of banks in the management of enterprises [1][2][3]. In fact, companies resort to banking indebtedness. The nature of the relationship between banks and enterprises depends on the country and the existing regulations. Unlike Germany and Japan, where financing takes place via banks, the Anglo-Saxon financial markets play an important role in the funding and control of companies. German companies maintain long term relationships with a Bank called "Hausbank". A fundamental characteristic of these banks is their participation in the companies' capital and funding them Moreover, the Japanese Keiretsu system enables banks to become shareholders and members in the Board of Directors. The bank ownership is a very widespread phenomenon in the Japanese banking systems and the continental Europe. The theory recognizes the ability of the bank holdings on the liabilities of big businesses to improve the control system of the leaders. Moreover, the presence of banks in the capital of companies improves the quality of information they have, wh...