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,...

Humans are fundamentally social. Social activities require coordination, which may yield multiple equilibria in the form of stable, self-reinforcing patterns of herd behavior. Since environmental impacts can differ substantially between alternative equilibria, such self-reinforcing behaviors...

Due to taxes and subsidies, gasoline prices vary dramatically across countries. Externalities cannot fully account for this. We develop a simple political economic model that shows that group interests, resulting from the composition of a country's car fleet, help to explain differences in...

Regulatory agencies frequently present violators with warnings, not pursuing prosecution if the violation ceases upon receipt of the warning. We show how such warnings may help regulators to keep control: Prosecution is costly for the regulator, and insu.cient prosecution e.orts yield low...

This paper explores the role of portfolio constraints in generating multiplicity of equilibrium. We present a simple financial market economy with two goods and two households, households who face constraints on their ability to take unbounded positions in risky stocks. Absent such constraints,...

Markets are incomplete when the assets available to the agents do not span the space of future contingencies. Efficiency is then assessed by the weak criterion of "constrained efficiency" (efficiency relative to the set of allocations compatible with the asset structure). That criterion requires...

Humans are fundamentally social. Social activities require coordination, which may yield multiple equilibria in the form of stable, self-reinforcing patterns of herd behavior. Since environmental impacts can differ substantially between alternative equilibria, such self-reinforcing behaviors...

This paper analyses the impact of multiple competitive equilibria and complete markets in a simple general equilibrium model. A random selection from the equilibrium correspondence of a finite exchange economy defines probability distributions on equilibrium prices. Asset markets allow traders...

Regulatory agencies frequently present violators with warnings, not pursuing prosecution if the violation ceases upon receipt of the warning. We show how such warnings may help regulators to keep control: Prosecution is costly for the regulator, and insu.cient prosecution e.orts yield low...

This paper shows that multiple and globally indeterminate long-run growth rates can easily arise in the two-sector growth model introduced by Lucas (1988). This result is generated by the existence of diminishing returns to time at the private level in human capital accumulation and the...