Essais dans la theorie de la structure du capital

My thesis presents three essays on capital structure theory. If the markets are perfect, there is no asymmetric information between participants and no transaction costs, capital structure is irrelevant. Therefore the corporate finance theory is mostly interested in the role of the market imperfections on firms' financing decisions.; The first essay studies the problems of financing under asymmetric information between firms' insiders and investors. Since the investors do not have enough information about the firms' future profits, the securities issued can be undervalued. This problem may lead to the rejection of some investment projects with positive net present value. Our approach in the first essay is based on a new idea that the managers may have long-term private information about firms' future performances, in particular about their profit profiles over time. The analysis shows that there is a link between a firm's profit profile over time and its financial policy.; Another problem of financing is that the long-term financial contracts are often incomplete. For example, it can be difficult to describe all circumstances in which a firm can be in the future. In these conditions it can be difficult for a firm to raise funds for financing because the investors do not have enough insurance that their resources will be spent efficiently. This implies that the control rights become extremely important. The design of securities should establish an optimal allocation of property rights between different claimholders. The second essay exploits the idea that the design of securities and the allocation of property rights depend on the potential conflict between the claimholders about the intertemporal substitution activities.; Finally, the third essay analyses an optimal financial contract in an environment where both the problems of asymmetric information and that of property rights allocation are presented simultaneously. This approach was not exploited so far in the literature. Another idea here is that the asymmetric information about the future profits may be more important than that about current profits.; The main results of the thesis are the following. First, asymmetric information about profit profiles over time is relevant to financing decisions. In particular, it explains the link between capital structure and business cycle, negative correlation between debt and profitability and long term afterissuing underperformance of firms issuing equity. Secondly, a potential conflict between the claimholders about the intertemporal substitution activities may explain the following important features of the optimal design of securities: residual property rights and current cash flow rights are linked by the rule of marginal revenues; there exist one convex and one concave contract; if the bankruptcy is optimal, the control should belong to the concave claimholder, if not to the convex claimholder. Third, debt is an optimal contract when there is asymmetric information between an entrepreneur and the market about the firm's future profits and when the property rights allocation is important.