This thesis combines different empirical strategies and econometric techniques to study the role of capital-market imperfections on the financial and operational activities of Small and Medium Enterprises (SME). It is mainly composed of four different but interlinked empirical chapters as follows. The first and the second chapters use longitudinal data from 9417 French SME start-up during period 1994-2000. The first empirical paper discusses develops and estimates a model of SME survival under credit rationing, we find that Asset- and human capital-based credit rationing exists but is mitigated by greater profitability and better human capital. The second chapter discuss how the collateral and human capital can be used as remedy for the credit rationing. The third one, we estimate the investment model by using switching regression approach by using panel data form 7,185 SME in the UK over year 2003–2011. The last chapter presents the investment cash flow sensitivity (ICFS) and Cash-cash flow sensitivity (CCFS) estimation for 14 European countries and we find that there is a positive and significant effect of cash flow on investment and cash holding on cash flow which indicating that there is some friction in the financial market in EU area.