We address the fundamental issues of existence and efficiency of an equilibrium in a Ramsey model with many agents, where agents have heterogeneous discounting, elastic labor supply and face borrowing constraints.The existence of rational bubbles is also tackled. In the first part, we prove the...

We develop a tractable model to study the macroeconomic impacts of limited arbitrage by linking arbitrage activities with the macroeconomy through collateralization. We show that the interactions between speculative trading and the business cycle can work as a powerful transmission mechanism,...