An economy faces an unknown individual risk, such as the health effects of a recently discovered environmental hazard. Opinions may be widely different about the distribution of risks across the population. We study financial markets that suffice to reach efficient allocations in this situation....

It is widely recognized that the value of environmental assets such as biodiversity, unique locations and the atmosphere may be hard to quantify. In particular, option values, quasi-option values and non-use values have been the subject of extensive discussion. We propose here an evaluation of...

An economy faces an unknown individual risk, such as the health effects of recently discovered environmental hazard. Opinions may be widely different about the distribution of risks across the population. We study financial markets that suffice to reach efficient allocations in this situation....

Consider an exchange economy with multiple competitive equilibria. Agents know the set of equilibria, but not which will be selected. To insure against unfavorable equilibrium outcomes, they trade on markets for commodities contingent on the equilibrium price vector. Such price-contingent...

We study the risks associated with the prospect of global climate change, and review the mechanisms available for their efficient allocation in market economies. Risks in this field are typically unknown and often unknowable ex ante; their probabilities are endogenous and determined by economic...

We consider contracts to purchase assets by means of streams of payments over time, with the asset as security. These give the purchaser an option not present if all payment is made up front, the option of stopping payments and delivering the asset in satisfaction of the remaining debt. We argue...