A classic characterization of competitive equilibria views them as feasible allocations maximizing a weighted sum of utilities. It has been applied to establish fundamental properties of the equilibrium notion, such as existence, determinacy, and computability. However, it fails for economies...

We develop the theory of demand for commodities and assets facing incompletely insurable uncertainty. First, a Slutsky matrix decomposes into substitution and income effects the derivative of demand with respect to prices and yield structure. Next, we identify the Slutsky matrix’s properties....

Financial innovation in an existing asset generically supports a Pareto improvement, targeting the income effect. This result, as several on taxation, owes to one unifying notion: that an intervention generically supports Pareto improvements if the implied price adjustment is sufficiently...

It is known that the incompleteness of asset markets causes inefficiency in almost every equilibrium. Yet unexplored is the ”size” of this inefficiency. The size of a Pareto improvement is the total willingness to pay for it, out of current consumption. Inefficiency is the maximum size of...

Focusing on tax policy with incomplete asset markets, we create a framework for proving the existence of Pareto improving taxes, for computing them, and for bounding the improvement. The protagonist is the price adjustment following an intervention. If the price adjustment is sufficiently...

We show that for generic economies, every equilibrium admits Pareto improving monetary policy, even with multiple commodities per state. The main assumption is that asset incompleteness be intermediate, in that household heterogeneity does not exceed the number of assets present and absent. We...

Samuelson (1947) stated that a regular equilibrium exhibits the transfer paradox if and only if it is unstable. Gale (1974) and many in the early 1980’s debunked this equivalence by adding extra countries, reaching an anti consensus. We reinterpret Samuelson’s result as identifying the...

A classic characterization of competitive equilibria views them as feasible allocations maximizing a weighted sum of utilities. It has been applied to establish fundamental properties of the equilibrium notion, such as existence, determinacy, and computability. However, it fails for economies...

A classic characterization of competitive equilibria views them as feasible allocations maximizing a weighted sum of utilities. It has been applied to establish fundamental properties of the equilibrium notion, such as existence, determinacy, and computability. However, it fails for economies...

When asset markets are incomplete there are almost always many Pareto improving policy interventions. Remarkably, these interventions do not involve adding any new markets. Focusing on tax policy, I create a framework for proving the existence of Pareto improving taxes, for computing them, and...