The paper analyzes an endogenous mechanism leading perfectly symmetric economies to diverge in the long run after unifying their financial asset markets. The standard growth model with overlapping generations of consumers (OLG) is extended to include uncertainty and a financial asset. In the absence of an international asset market, the two autarkic economies converge to the same globally attracting steady state under rational expectations dynamics. When the two asset markets are unified internationally, additional asymmetric steady states appear, implying that the steady state with equal levels of capital becomes unstable, causing symmetry breaking. The paper derives general sufficient conditions for a saddle node bifurcation of the symmetric steady state. A numerical example shows that these effects occur, in particular when the production function and the function of absolute risk aversion are isoelastic.

This paper analyzes the behavior of a central bank under strong (“Knightian”) uncertainty when the short-run trade-off between output and inflation is represented by the sticky information Phillips curve proposed by Mankiw and Reis [Quarterly Journal of Economics 117(4), 1295–1328 (2002)]. By solving the robust control problem analytically, we show why model uncertainty does not affect the optimal monetary policy response to demand and productivity shocks, whereas it causes a stronger reaction of the monetary policy instrument to a cost-push (i.e., markup) shock. Differently from what occurs in sticky price models, the antiattenuation effect can result in a degree of price level stabilization that is greater or less than that experienced in the rational expectation model, depending on the central bank's degree of conservatism. These results dramatically affect the rationale for delegating monetary policy to a central banker more conservative than the society.

This paper studies the long- and short-run relationships between inflation and financial development. Applying the Pooled Mean Group estimator of Pesaran, Shin, and Smith (1999, Journal of the American Statistical Association 94, 621–634) to unbalanced panel data for 87 countries over the period 1960–2005, we find that a negative long-run relationship between inflation and financial development coexists with a positive short-run relationship. However, when the data are split into different income or inflation groups, these results can be observed only in low-income or low-inflation economies.

The effects of inflation are studied for a small open economy with a cash-in-advance constraint on consumption in which the representative agent has preferences with habit persistence. An increase in the inflation rate requires a fall in the steady state living standards. On impact, to maintain living standards, the representative agent reduces his savings and labor supply. Investment falls and the current account turns into a deficit. In support of this model, we provide evidence from eight high-inflation countries suggesting that after an increase in the inflation rate, output and investment fall, and the net foreign asset position deteriorates over time.

Roger Guesnerie is a prominent economic theorist. Among his many honors and distinctions, he is a Foreign Member of the American Academy of Arts and Science and an Honorary Foreign Member of the American Economic Association; he has been a President of the European Economic Association and of the Econometric Society. Currently a Professor at the College de France, he has made fundamental contributions to second-best theory and public economics, information economics, and rational expectation theory.

Guesnerie was one of the founding fathers of second-best theory. His contributions to public economics, addressing issues such as nonconvex economies and especially taxation in a second-best context, remain absolute references on these topics; more recently, he has provided an in-depth analysis of issues related to climate change and global warming from a public economics perspective. Regarding contract theory, his work with Jean Jacques Laffont has considerably extended our understanding of the properties of the basic models, as well as the set of tools that economists can use to address these problems. Finally, Guesnerie's work has been influential in the critical reassessment of rational expectation theory that took place over the last decades. On one hand, he has been a prominent figure in the development of so-called “sunspot” models, which reconcile the Keynesian notion of “animal spirits” with the formal requirements of rational expectations. On the other hand, he has provided path-breaking discussions of the theoretical relevance of rational expectation theory, based on a detailed assessment of the coordination between individual expectations that is implicit in the concept. In some classes of models, Guesnerie argues, rational expectation equilibria constitute a natural outcome, because coordination can be achieved either through “eductive” reasoning (for which common knowledge of individual rationality is sufficient) or as the product of simple evolutionary or learning dynamics (and in general in both ways). In other cases, however, such arguments do not appear to support the rational expectations solution, and its relevance is therefore much less obvious. On a more institutional side, Guesnerie has created the doctoral program “Analyse et Politique Economique” at the Ecole des Hautes Etudes en Sciences Sociales; besides this program, in 1989, several related research centers in Paris merged into Delta, which Guesnerie chaired between 1992 and 2000, and then into the Paris School of Economics (PSE), at which Guesnerie is Chairman of the Board.

This interview with Roger Guesnerie gives an opportunity to discuss further the current situation of economic theory and economics in general, as well as to compare the European and American traditions in economics.

This paper develops a dynamic stochastic general equilibrium (DSGE) model with sticky prices and sticky wages, in which agents have imperfect information on the stance and direction of monetary policy. Agents respond by using Kalman filtering to unravel persistent and temporary monetary policy changes in order to form optimal forecasts of future policy actions. Our results show that a New Keynesian model with imperfect information and real rigidities can account for several key effects of an expansionary monetary policy shock: the hump-shaped increase in output, the delayed and gradual rise in inflation, and the fall in the nominal interest rate.