Optimal Asset Taxes in Financial Markets with Aggregate Uncertainty

This paper studies Pareto-optimal risk-sharing arrangements in a private information economy with aggregate uncertainty and ex ante heterogeneous agents. I show how to implement Pareto-optima as equilibria when agents can trade claims to consumption contingent on aggregate shocks in financial markets. The first result is that if aggregate and idiosyncratic shocks are independent, the implementation of optimal allocations does not require any interventions in financial markets. This result can be extended to dynamic settings in the sense that, in this case, only savings need to be distorted, but not trades in financial markets. Second, I characterize optimal trading distortions in financial markets when aggregate and idiosyncratic shocks are not independent. In this case, optimal asset taxes must be higher for those securities that pay out in aggregate states in which consumption is more volatile. For instance, this can provide an efficiency justification for the frequently observed differential tax treatment of different asset classes, such as debt and equity claims.

Competitive Screening in Insurance Markets with Endogenous Wealth Heterogeneity

We examine equilibria in competitive insurance markets with adverse selection when wealth differences arise endogenously from unobservable savings or labor supply decisions. The endogeneity of wealth implies that high risk individuals may ceteris paribus exhibit the lower marginal willingness to pay for insurance than low risks, a phenomenon that we refer to as irregular-crossing preferences. In our model, both risk and patience (or productivity) are privately observable. In contrast to the models in the existing literature, where wealth heterogeneity is exogenously assumed, equilibria in our model no longer exhibit a monotone relation between risk and coverage. Individuals who purchase larger coverage are no longer higher risks, a phenomenon frequently observed in empirical studies.Insurance Markets, Adverse Selection, Multidimensional Screening

Competitive Screening in Insurance Markets with Endogenous Labor Supply

We examine equilibria in competitive insurance markets when individuals take unobservable labor supply decisions. Precautionary labor motives intro-duce countervailing incentives in the insurance market, and equilibria with positive profits can occur even in the standard case in which individuals exogenously differ in risk only. We then extend the model to allow for both privately known risks and labor productivities. This endogenously introduces two-dimensional heterogeneity in the insurance market since precautionary labor effects lead to differences in income and hence risk aversion. Under these circumstances, separating and pooling equilibria exist, which generally differ from those with exogenous two-dimensional heterogeneity considered by the existing literature. Notably, in contrast to standard screening models, profits may be increasing with insurance coverage, and the correlation between risk and coverage can be zero or negative in equilibrium, a phenomenon frequently observed in empirical studies.Insurance markets, adverse selection, precautionary labor

Competitive Markets without Commitment

In the presence of a time-inconsistency problem with optimal agency contracts, we show that competitive markets implement allocations that Pareto dominate those achieved by a benevolent planner, they induce strictly more effort, and they sometimes make the commitment problem disappear entirely. In particular, we analyze a model with moral hazard and two-sided lack of commitment. After agents have chosen a hidden effort and the need to provide incentives has vanished, firms can modify their contracts and agents can switch firms. As long as the ex-post market outcome satisfies a weak notion of competitiveness and sufficiently separates individuals who choose different effort levels, the market allocation is Pareto superior to a social planner’s allocation. We construct a specific market game that naturally generates robust equilibria with these properties. In addition, we show that equilibrium contracts without commitment are identical to those with full commitment if the latter involve no cross-subsidization between individuals who choose different effort levels.Time-Inconsistency, Moral Hazard, Competitive Markets, Adverse Selection

A Grexit may be plausible from an economic perspective, but politically it would be a disaster

Should the rest of Europe be concerned by the consequences of Greece leaving the Eurozone? Florian Schui writes that while from an economic perspective a Grexit is entirely manageable, from a political perspective it would be a disaster for the EU. He argues that Greece leaving the euro would send the message that European leaders are more willing to allow the Eurozone to break up than they are to abandon austerity policies

Taxation, Insurance and Precautionary Labor

We examine optimal taxation and social insurance if insurance markets are imperfect. This requires the development of a theory of labor supply under uncertainty. We show that the case for social insurance is not generally reinforced by adverse selection in insurance markets as social insurance will have welfare-decreasing effects on the labor market. Furthermore, positive and normative implications are highly sensitive to the insurance market equilibrium concept. While for the Rothschild-Stiglitz case social insurance at least alleviates the inefficiency of underinsurance, with a Wilson pooling equilibrium this inefficiency might even be worsened by social insurance. This sheds new light on the question whether social insurance is an appropriate means of redistribution in the presence of an optimally chosen tax schedule

Optimal Taxation with Rent-Seeking

We develop a framework for optimal taxation when agents can earn their income both in traditional activities, where private and social products coincide, and in rent-seeking activities, where private returns exceed social returns either because they involve the capture of pre-existing rents or because they reduce the returns to traditional work. We characterize Pareto optimal non-linear taxes when the government does not observe the shares of an individual's income earned in each of the two activities. We show that the optimal externality correction typically deviates from the Pigouvian correction that would obtain if rent-seeking incomes could be perfectly targeted, even at income levels where all income is from rent-seeking. If rent-seeking externalities primarily affect other rent-seeking activity, then the optimal externality correction lies strictly below the Pigouvian correction. If the externalities fall mainly on the returns to traditional work, the optimal correction strictly exceeds it. We show that this deviation can be quantitatively important

Signaling to experts

We study competitive equilibria in a signaling economy with heterogeneously informed buyers. In terms of the classic Spence (1973) model of job market signaling, firms have access to direct but imperfect information about worker types, in addition to observing their education. Firms can be ranked according to the quality of their information, i.e. their expertise. In equilibrium, some high-type workers forgo signaling and are hired by better informed firms, which make positive profits. Workers’ education decisions and firms’ use of their expertise are strategic complements, allowing for multiple equilibria that can be Pareto ranked. We characterize wage dispersion and the extent of signaling as a function of the distribution of expertise among firms. Our model can also be applied to a variety of other signaling problems, including securitization, corporate financial structure, insurance markets, or dividend policy

Competitive Markets without Commitment

In the presence of a time-inconsistency problem with optimal agency contracts, we show that competitive markets implement allocations that Pareto dominate those achieved by a benevolent planner, they induce strictly more effort, and they sometimes make the commitment problem disappear entirely. In particular, we analyze a model with moral hazard and two-sided lack of commitment. After agents have chosen a hidden effort and the need to provide incentives has vanished, firms can modify their contracts and agents can switch firms. As long as the ex-post market outcome satisfies a weak notion of competitiveness and sufficiently separates individuals who choose different effort levels, the market allocation is Pareto superior to a social planner's allocation. We construct a specific market game that naturally generates robust equilibria with these properties. In addition, we show that equilibrium contracts without commitment are identical to those with full commitment if the latter involve no cross-subsidization between individuals who choose different effort levels

Optimal taxation with rent-seeking

We develop a framework for optimal taxation when agents can earn their income both in traditional activities, where private and social products coincide, and in rent-seeking activities, where private returns exceed social returns either because they involve the capture of pre-existing rents or because they reduce the returns to traditional work. We characterize Pareto optimal income taxes that do not condition on how much of an individual's income is earned in each of the two activities. These optimal taxes feature an externality-corrective term, the magnitude of which depends both on the Pigouvian correction that would obtain if rent-seeking incomes could be perfectly targeted and on the relative impact of rent-seeking externalities on the private returns to traditional and to rent-seeking activities. If rent-seeking externalities primarily affect other rent-seekers, for example, the optimal correction lies strictly below the Pigouvian correction. A calibrated model indicates that the gap between the Pigouvian and optimal correction can be quantitatively important. Our results thus point to a hefty informational requirement for correcting rent-seeking externalities through the income tax code