Search Theory: The 2010 Nobel Memorial Prize in Economic Sciences

This paper surveys search theory with an emphasis on the contributions of the 2010 laureates for the Nobel Memorial Prize in Economic Sciences, Peter Diamond, Dale Mortensen, and Christopher Pissarides.     

The Nobel Memorial Prize for William D. Nordhaus

William D. Nordhaus and Paul M. Romer received the 2018 Sveriges Riksbank Prize in Economic Sciences in Memory of Alfred Nobel. This paper surveys Nordhaus’ contributions on “integrating climate change into long‐run macroeconomic analysis”, for which he was recognized with this Prize.     

The role of independence in the Green-Lin Diamond-Dybvig model

Green and Lin study a version of the Diamond-Dybvig model with a finite number of agents, independence (independent determination of each agent's type), and sequential service. For special preferences, they show that the ex ante first-best allocation is the unique equilibrium outcome of the model with private information about types. Via a simple argument, it is shown that uniqueness of the truth-telling equilibrium holds for general preferences—and, in particular, for a constrained-efficient allocation whether first-best or not. The crucial assumption is independence.     

The impact of changing skill levels on optimal nonlinear income taxes

The impact of changing an individual's skill level on the solution to a finite population version of the Mirrlees optimal nonlinear income tax problem with quasilinear-in-leisure preferences is investigated. It is shown that it is possible to sign the directions of change in everyone's optimal consumptions and optimal marginal tax rates in response to such a change.     

Putting the "New" into New Trade Theory: Paul Krugman's Nobel Memorial Prize in Economics

This paper reviews the scientific contributions of Paul Krugman to the study of international trade, on the occasion of his receipt of the 2008 Nobel Memorial Prize in Economics. A simplified exposition is presented of some of his principal findings, including: the effects of trade on firm scale and product diversity in a general model of monopolistic competition; the integration of monopolistic competition with factor endowments theory; the implications of transport costs, including home-market effects and the possibility of agglomeration in models of economic geography; and the positive and normative consequences of oligopolistic trade.     

Implementing efficient allocations in a model of financial intermediation

In a finite-trader version of the Diamond and Dybvig (J. Polit. Econ. 91 (1983) 401) model, the ex ante efficient allocation is implementable by a direct mechanism (i.e., each trader announces the type of his own ex post preference) in which truthful revelation is the strictly dominant strategy for each trader. When the model is modified by formalizing the sequential-service constraint (cf. Wallace (Fed. Reserve Bank Minneapolis Quart. Rev. 12 (1988) 3)), the truth-telling equilibrium implements the symmetric, ex ante efficient allocation with respect to iterated elimination of strictly dominated strategies.     

Corrigendum to “Reserve price signaling” [J. Econ. Theory 135 (1) (2007) 253-268]

We find an error in [H. Cai, J. Riley, L. Ye, Reserve price signaling, J. Econ. Theory 135 (1) (2007) 253-268]. The existence of the separating signaling equilibrium is not challenged, but the related comparative statics, while valid in the case without informational externalities between bidders, do not generalize to the case with informational externalities as claimed by the authors. General results on the influence of the number of bidders are obtained in a linear specification of the informational externalities.     

Bank incentives, contract design and bank runs

We study the Diamond-Dybvig [Bank runs, deposit insurance, and liquidity, J. Polit. Econ. 91 (1983) 401-419] model as developed in Green and Lin [Implementing efficient allocations in a model of financial intermediation, J. Econ. Theory 109 (2003) 1-23] and Peck and Shell [Equilibrium bank runs, J. Polit. Econ. 111 (2003) 103-123]. We dispense with the notion of a bank as a coalition of depositors. Instead, our bank is a self-interested agent with a technological advantage in record-keeping. We examine the implications of the resulting agency problem for the design of bank contracts and the possibility of bank-run equilibria. For a special case, we discover that the agency problem may or may not simplify the qualitative structure of bank liabilities. We also find that the uniqueness result in Green and Lin [Implementing efficient allocations in a model of financial intermediation, J. Econ. Theory 109 (2003) 1-23] is robust to our form of agency, but that the non-uniqueness result in Peck and Shell [Equilibrium bank runs, J. Polit. Econ. 111 (2003) 103-123] is not.     

Direct versus intermediated finance: An old question and a new answer

We consider a closed economy where a risk neutral bank competes with a competitive bond market. Firms can finance a risky project either by a bank credit or by issuing a bond which is directly sold to risk averse investors who also hold safe deposits at the bank. We show that the bank tends to allocate more capital to lower quality projects but there are some interesting qualifications. If the asymmetric information concerns only the success probability, then we observe adverse selection while if it concerns only the expected return, bad types are driven out of the market.     

Optimal nonlinear income taxation with a finite population

In the standard optimal income taxation problem, tax payments depend only on each consumer's own actions. Piketty [J. Econ. Theory 61 (1993) 23-41] shows that, if one individual's tax schedule depends on others’ actions and the government knows the exact ability distribution, it can implement any undistorted allocation as the unique revelation game outcome. If some individuals misreveal their types, Piketty's mechanism may assign infeasible allocations. We require that tax schedules must balance the government budget for every possible vector of revelations. When individuals reveal their type by simple announcements, all undistorted allocations can be still implemented, even with off-equilibrium feasibility constraints.     

Bank Mergers, Information, Default and the Price of Credit

This paper addresses the impact of bank mergers on the price of firm credit, through an information channel. It is shown that, as bank mergers imply a wider spreading of information among banks concerning firms' past defaults, they may increase the expected revenue from lending. Therefore, interest rates may decline as long as a sufficiently competitive environment is preserved. A fall in interest rates, in turn, reduces the incentives for firms to strategically default, which reinforces the downward effect on the price of credit. The results are a function of the level of information sharing and of the sensitivity of the default probability to the interest rate .     

The Nobel Memorial Prize in Economics 1996: Press Release from the Royal Swedish Academy of Sciences

The Royal Swedish Academy of Sciences has decided to award the Bank of Sweden Prize in Economic Sciences in Memory of Alfred Nobel, 1995, to Professor James A. Mirrlees , University of Cambridge, UK and Professor William Vickrey , Columbia University, New York, USA for their fundamental contributions to the economic theory of incentives under asymmetric information.