This thesis studies the interactions between financial markets, monetary policy, and the real economy. It analyses the role of financial markets in business cycle fluctuations and explores issues concerning systemic financial stability. Chapter One develops a dynamic general equilibrium model in which firms and banks face financial frictions in obtaining external funds. The model exhibits an unconventional bank capital channel as monetary policy affects the economy partly via its effect on bank capital. We show that the dynamic interactions between bank capital, firm net worth and asset price amplify and propagate the effect of a monetary shock in the macroeconomy. Chapter Two empirically investigates the importance of financial markets in ...