In this paper I generalize the following rule of Ramsey (1928) on the discount rate with regime switching: the discount rate is the sum of the rate of pure time preference and the product of the consumption elasticity of marginal utility and the consumption growth rate. The Ramsey rule can be...

A central conjecture of behavioural finance is that arbitrage opportunities appear as a result of systematic irrational investment behaviour and persist since real-world arbitrage trades actually involve costs and risks due to market frictions and non-fundamental risk. This paper shows that the...

Rational bubbles in stocks can cause increases in trading volume, even after accounting for their expansionary effect on output and consumption. Trading volume increases are not caused by speculation driven by differences in beliefs. Dividend-bearing assets used to transfer resources...

We show that an intrinsic property of a large class of rational bubbles is their capacity to relax the agents' debt limits. Any bubble that preserves the set of pricing kernels, or equivalently, the asset span, has effectively an identical effect on consumption and real interest rates as an...

Our paper provides a complete characterization of leverage and default in binomial economies with financial assets serving as collateral. First, our Binomial No-Default Theorem states that any equilibrium is equivalent (in real allocations and prices) to another equilibrium in which there is no...

The solution to dynamic portfolio choice models can be formulated in terms of a value function by the Bellman principle of optimality, which reduces the multi-period optimal policy choice problem to a sequence of one-period maximization problems. For two adjacent periods, economists compute the...

Many capital structures implicitly or explicitly give agents the ability to use debt contracts as collateral for other financial promises. We study the effects of allowing debt to be used as collateral in a general equilibrium model with heterogeneous agents, collateralized financial contracts,...

Given a market with a price process S populated by heterogeneous traders with differential information, beliefs, and trading constraints, let the smallest information set containing all of the traders' information be denoted F. This market is defined to be informationally efficient (Fama [2])...

Given a market with a price process S populated by heterogeneous traders with differential information, beliefs, and trading constraints, let the smallest information set containing all of the traders' information be denoted F. This market is defined to be informationally efficient (Fama [2])...