Alessandro Citanna

Two-sided matching with interdependent values

We introduce and study two-sided matching with incomplete information and interdependent valuations on one side of the market. An example of such a setting is a matching market between colleges and students in which colleges receive partially informative signals about students. Stability in such markets depends on the amount of information about matchings available to colleges. When colleges observe the entire matching, a stable matching mechanism does not generally exist. When colleges observe only their own matches, a stable mechanism exists if students have identical preferences over colleges, but may not exist if students have different preferences.

Occupational choice, incentives and wealth distribution☆

Abstract We consider a model of occupational choice in large economies where individuals differ in their wealth endowment. Individuals can remain self-employed or engage in productive matches with another individual, i.e., form firms. Matches are subject to a moral hazard problem with limited liability. The division of the gains from such matches is determined by competitive forces. When the incentive problem is asymmetric, matches are typically wealth-heterogeneous, with richer individuals choosing the occupation for which incentives are more important. The utilities attained within a match depend on the wealth distribution and changes in the latter give rise to ‘trickle down’ effects.

Incomplete Markets, Allocative Efficiency and the Information Revealed by Prices

We compare rational expectations equilibria with different degrees of information revelation through prices. These equilibria arise in a two-period exchange economy with finitely many states and signals, multiple commodities and incomplete financial markets for nominal assets. We show that there are always equilibria where information is redundant in the sense of being of no value to the uninformed traders. We give conditions under which for a generic set of economies, parametrized by endowments and utilities, there exist open sets of equilibria for which allocative and informational efficiency are independent, with implications for monetary policy.

Competitive equilibrium with moral hazard in economies with multiple commodities

We study an economy with competitive commodity markets and exclusive pairwise contractual relations with moral hazard, where both the principal and the agent can be risk averse. We show existence of equilibria and their generic constrained suboptimality, by means of a change in the compensation schemes. Such suboptimality occurs provided the number of commodities is sufficiently large relative to the number of states and pair types, and there are at least three future states of the world.

Short-memory equilibrium in stochastic overlapping generations economies

Abstract In stochastic OLG exchange economies, we show that short-memory equilibria—the natural extension from deterministic economies of steady states, low-order cycles, or finite state-space stationary sunspots equilibria—fail to exist generically in utilities. As a result, even with independent and identically distributed exogenous shocks there is serial correlation in endogenous economic variables in equilibrium. This arises even if utilities are time-separable, some goods inferior, and there are no technological lags. Hence, the origins of economic fluctuations can be traced only to the demographic structure of a heterogeneous agent, multiple-good economy.

INCENTIVE EFFICIENT PRICE SYSTEMS IN LARGE INSURANCE ECONOMIES WITH ADVERSE SELECTION

We decentralize incentive efficient allocations in large adverse selection economies by introducing a competitive market for mechanisms, that is, for menus of contracts. Facing a budget constraint, informed individuals purchase (lottery) tickets to enter mechanisms, whereas firms sell tickets and supply slots at mechanisms at given prices. Beyond optimization, market clearing, and rational expectations, an equilibrium requires that firms cannot favorably change, or cut, prices. An equilibrium exists and is incentive efficient. An equilibrium can be computed as the solution to a programming problem that selects the incentive efficient outcome preferred by the highest type within an appropriately defined set. For two‐types economies, this is the only equilibrium outcome.

Proportional transaction costs on asset trades : a note on existence by homotopy methods

We prove existence of equilibria with proportional transaction costs on asset trading, using homotopy methods.

Refinements and Incentive Efficiency in Walrasian Models of Insurance Economies

The literature on Walrasian markets in large economies with adverse selection has used various equilibrium refinements, but has obtained no general incentive efficiency of equilibrium, namely when cross-subsidies are needed for efficiency. We show that the same refined equilibria may also be incentive inefficient, even when mechanisms that allow for such cross-subsidies are priced and can be traded. In the process, we also prove existence of some type of forward induction equilibria in this context.

Financial Innovation and Price Volatility

In a three-period finite competitive exchange economy with incomplete financial markets and retrading, we show the generic existence of financial innovation which decreases equilibrium price volatility (as well as innovation which increases it). The existence is obtained under conditions of sufficient market incompleteness. The financial innovation may consist of an asset which is only traded at time zero, or retraded, and with payoffs only at the terminal date. The existence is shown to be robust in the asset payoff space.