Equilibrium indeterminacy due to economies of scale (ES) in financial intermediation is quantitatively examined in a monetary business-cycle environment. Financial intermediation provides deposits that serve as a substitute for currency to purchase consumption, and depositing decisions are susceptible to nonfundamental shocks to confidence. The analysis considers various assumptions on nominal rigidities and the timing of deposit decisions. The results suggest that indeterminacy arises for small ES, and the resulting confidence shocks qualitatively mimic monetary shocks. A calibration exercise concludes that U.S. economic volatility from this nonfundamental source has increased over time while volatility from fundamental sources has decreased.

A static economy in which nominal taxes and transfers are balanced, as proposed by Balasko and Shell (1993), typically has a continuum of equilibrium money prices. This paper presents a constructive example in which the set of equilibrium money prices is not connected. By allowing negative consumption as a mathematical construct, closed form solutions for equilibrium tax-adjusted income are derived. The main result of the example implies that bankrupt taxpayers with negative tax-adjusted income can be free from bankruptcy as the price of money increases. This paradoxical outcome is similar to that of the transfer paradox, as suggested by Gale (1974), where tax-transfer plans make taxpayers better off.

This interview was completed in May 2004, well before Stan Fischer had any idea he would become Governor of the Bank of Israel, a position he took up in May 2005. The interview took place in April 2004 in my office at the Russell Sage Foundation in New York City, where I was spending a sabbatical year. We completed it while running together in Central Park during the following weeks.

Our meeting at Russell Sage was just like the many meetings we have had over the years. I was not sitting with a Master of the Universe, a world VIP, but with the same Stan Fischer I had first met in 1973 when he was a young associate professor, freshly imported from Chicago. There was the same ability to listen carefully, the same ability to talk and to explain simply and straightforwardly. In addition, there was the accumulated wisdom of a professional life spent developing and applying macroeconomics to the very real world.

When I arrived as a PhD student at MIT in 1973, it was clear that Stan would quickly play a central role in the department. Within a few years, he was one of the most popular teachers, and one of the most popular thesis advisers. We flocked to his office, and I suspect that the only time for research he had was during the night. What we admired most were his technical skills (he knew how to use stochastic calculus)—, and his ability to take on big questions and to simplify them to the point where the answer, ex post, looked obvious. When Rudi Dornbusch joined him in 1975, macro and international quickly became the most exciting fields at MIT. Imitation is the sincerest form of admiration, and this is very much what we all did.

When I came back to MIT in 1982, this time as a faculty member, Stan had acquired near-guru status. Teaching the advanced macro courses with him, and writing “Lectures on Macroeconomics,” which we finished in 1988, was one of the most exciting intellectual adventures of my life. We both felt that there was a new macroeconomics, more micro-founded and full of promises and that we understood its architecture and its usefulness. Although we had not thought of it as a textbook, it quickly became one, and it is nice to know that it still sells surprisingly well today.

As the years had passed, Stan had taken more and more interest in applying theory to the real world, working with Rudi on hyperinflation, being involved in the economics of peace with George Shultz in the Middle East. In 1988, he decided to jump from academia to the real world, and became Chief Economist of the World Bank. After a brief return to MIT, he then returned to Washington in 1994 to become First Deputy Managing Director of the IMF, where he remained until 2001. That part of his life has been well documented in newspapers and magazines: While at the IMF, he was on the front lines during the Mexican crisis, the Russian crisis, the Asian crises, and many others. From the peeks I got of him during those times, what strikes me most is how he remained the same as he had been at MIT: calm, careful about the facts, analytical, using macroeconomic theory even in the middle of the most intense fires. Many thought and hoped that he would become the managing director of the IMF. Antiquated rules and country politics prevented it from happening. The IMF's loss turned out to be the private sector's gain. In 2002, Stan joined Citigroup, where he is the President of Citigroup International. He is still active in macro policy debates and remains one of the wise men of our profession.

In this paper I study the impact of increasing longevity on pay-as-you-go pension systems. First, I show that increasing longevity increases the internal rate of return. The size of the effect differs for different policy regimes. It is higher for the case where the retirement age is increased to keep the system in balance than for the case where the necessary adjustment is achieved by reducing pension benefits. Second, I study optimally chosen retirement decisions and I show that the socially optimal policy involves a shorter working life than the private optimum. The social optimum can be implemented by the use of a PAYG system that combines an actuarial and a flat pension.

We study production functions with capital and labor as arguments that exhibit positive, yet diminishing marginal products and constant returns to scale. We show that such functions satisfy the Inada conditions if (i) both inputs are essential and (ii) an unbounded quantity of either input leads to unbounded output. This allows for an alternative characterization of the neoclassical production function that altogether dispenses with the Inada conditions. Although this proposition generalizes to the case of n > 2 factors of production, its converse does not hold: 2n Inada conditions do not imply that each factor is essential.

We develop a model with financial frictions and sovereign default risk wherein the maturity of public debt is allowed to be larger than one period. When the debt portfolio has longer average maturities, public debt increases less in the event of a crisis, reducing the size of the subsequent fiscal consolidation through distorsionary taxes or public spending, with positive effects on welfare. In addition, we provide some results suggesting that optimized fiscal responses to a crisis depend on the average maturity of the debt portfolio.

There is no consensus on the existence of welfare gains from international monetary policy cooperation. This study adds to the debate by providing a new open macroeconomics model with incomplete exchange rate pass-through. We find that, from a global perspective, the welfare gains from international monetary policy cooperation arise with incomplete exchange rate pass-through. Furthermore, the country’s incentive for cooperation increases with its degree of exchange rate pass-through. Cooperation benefits small countries with high pass-through; however, it is disadvantageous to large countries with low pass-through. In addition, when there is in the absence of cooperation, fixed exchange rate regime is preferred for a country suffering from monetary uncertainty, particularly for small economies with high exchange rate pass-through.

This paper shows, in an overlapping-generations economy à la Diamond [American Economic Review 55, 1126–1150 (1965)], that when savings in an unbacked asset (e.g., fiat money) bear some risk of becoming suddenly worthless, the market does not implement the best steady state attainable with that asset. Nonetheless, in the absence of absolutely riskless fiat money and excluding resorting to redistributive fiscal policies that would make it possible to attain the first-best steady state, this best monetary steady state can be implemented as a competitive equilibrium with the adequate policy of taxes on returns to capital, subsidies to returns to monetary savings, and lump-sum transfers. The policy is, at the steady state, balanced every period and nonredistributive.

The fiscal theory of the price level says that the price level can be made determinate if the government uses fiscal policies such that government liabilities explode unless the price in the first period is at the “right” level. The policy implications are disturbing, as they call for rather adventurous fiscal policies. We show that these disturbing policy implications are specific to the “Ricardian” models that have been used to develop the theory. By moving to non-Ricardian models, we see that price determinacy is consistent with reasonable fiscal policies.

Growth in total factor productivity (TFP) in the USA has slowed down significantly since the mid-2000s, reminiscent of the productivity slowdown of the 1970s. This paper investigates the implications of a productivity slowdown on macroeconomic variables using a standard real business cycle (RBC) model, extended with regime-switching in trend productivity growth and Bayesian learning regarding the growth regime. I estimate the Markov-switching parameters using US data and maximum-likelihood methods, and compute the model solution using global projection methods. Simulations reveal that, while adding a regime-switching component to the standard RBC setup increases the volatility in the system, further incorporating incomplete information and learning significantly dampens this effect. The dampening is mainly due to the responses of investment and labor in response to a switch in the trend component of TFP growth, which are weaker in the incomplete information case as agents mistakenly place some probability that the observed decline in TFP growth is due to the transient component and not due to a regime switch. The model offers an objective way to infer slowdowns in trend productivity, and suggests that macroeconomic aggregates in the USA are currently close to their potential levels given observed productivity, while counterfactual simulations indicate that the cost of the productivity slowdown to US welfare has been significant.

By studying complete and incomplete dynamic financial markets, I show that if some agents are money-illusioned and neglect inflation, the rational agents who are aware of inflation are driven out of the market in the long run, in the sense that the money-illusioned agents consume the economy's entire endowment. The reason for this finding is that with inflation, the money-illusioned agents always believe that the return on their savings is higher than it actually is. Because these agents trade financial assets in markets with the rational agents, the rational agents end up being borrowers and the money-illusioned agents lenders. Because the rational agents' debt accumulates over time, they become so indebted that the money-illusioned agents eventually consume the economy's entire endowment. If there is deflation, the opposite is true, and the rational agents evolutionarily dominate.

I analyze the impact of intellectual property and product market competition regulations on innovation and long-run growth in an endogenous growth model with two R&D performing sectors. I show that strengthening intellectual property rights and competition in a sector increases its R&D investments. However, these policies adversely affect R&D investments in the other sector because of increased factor competition between the sectors. As a result, the overall impact of such policies on economic growth is ambiguous. I perform a numerical exercise in an attempt to resolve this ambiguity. This exercise suggests that strengthening intellectual property rights increases economic growth, but higher competition has a very limited effect on growth.

One usually identifies bubble solutions to linear rational expectations models by extra components (irrelevant lags) arising in addition to market fundamentals. Although there are still many solutions relying on a minimal set of state variables, i.e., relating in equilibrium the current state of the economic system to as many lags as initial conditions, there is a conventional wisdom that the bubble-free (fundamentals) solution should be unique. This paper examines the existence of endogenous stochastic sunspot fluctuations close to solutions relying on a minimal set of state variables, which provides a natural test for identifying bubble and bubble-free solutions. It turns out that only one solution is locally immune to sunspots, independently of the stability properties of the perfect-foresight dynamics. In the standard saddle-point configuration for these dynamics, this solution corresponds to the so-called saddle stable path.

This paper studies how search externalities and wage bargaining distort vacancy creation and the allocation of workers to jobs in markets with two-sided heterogeneity. To do so, I propose a model of a frictional labor market where heterogeneous workers decide which job to look for and firms decide which technology to adopt. At equilibrium, there is perfect segmentation across sectors, which is determined by a unique threshold of workers' productivity. This threshold is inefficient because of participation and composition externalities. The Pigouvian tax scheme that decentralizes optimal sorting shows that these externalities have opposite signs. Furthermore, their relative strength depends on the distribution of workers' skills, so that when there are many (few) skilled workers, too many (few) high-technology jobs are created.

This paper analyzes whether the Fed had the ability through its conventional monetary policy to affect key economic and financial variables, and, in particular, the term structure of interest rates, during the recent financial crisis. This departs from the empirical literature that focuses mainly on the effectiveness of unconventional monetary policies during this episode, although these policies are appropriate only to the extent that the conventional policy was ineffective in the first place. Our identification strategy based on the conditional heteroskedasticity of the structural innovations allows us to specify a flexible structural vector auto-regressive process that relaxes the identifying assumptions commonly used in earlier studies. Comparing our results obtained from samples excluding and including the financial crisis, we find that the conventional monetary policy has lost its effectiveness shortly after the beginning of the financial turmoil. This result suggests that the Fed's use of unconventional policies was appropriate, at least, with the objective of changing the term structure of interest rates.

Much empirical evidence finds that governments react to fiscal imbalances in a nonlinear way, through an increasing marginal response of primary surpluses to changes in debt. This paper shows that nonlinear fiscal regimes alter equilibria under active and passive monetary–fiscal policies. The Fisher equation combined with nonlinear fiscal policies leads to multiple steady states. Under passive interest rate rules, even if the steady state in which fiscal policy is active is locally saddlepath stable, there exist infinite equilibrium paths originating in the neighborhood of that steady state that converge into a high-debt trap. Under active interest rate rules, even if the steady state at which fiscal policy is active is locally unstable, there exists a saddle connection with the high-debt equilibrium along which inflation is uniquely determined.

This paper provides a closed-form solution to a standard asset pricing model with habit formation when the growth rate of endowment follows a first-order Gaussian autoregressive process. We determine conditions that guarantee the existence of a stationary bounded equilibrium. The findings are useful because they allow to evaluate the accuracy of various approximation methods to nonlinear rational expectation models. Furthermore, they can be used to perform simulation experiments to study the finite sample properties of various estimation methods.

Many recent digital innovations (like video games) augment the value of leisure time, which is not captured by Gross Domestic Product. Therefore, the productivity impact of such innovations may be understated. I develop the theoretical foundations for measuring the value of leisure when it is produced using the household’s leisure time and recreational durable goods. I apply this framework to estimate the value of US leisure from 1948 to 2016. While the value of leisure is large, it has become less important over time. I find that productivity growth of leisure time has slowed in the digital era. Household stocks of digital goods are small, so have relatively little impact on leisure value. I conclude that mismeasurement due to household digital goods is not a first-order cause of the recent productivity slowdown.

We build a two-country model of endogenous growth to study the welfare effects of taxes on tradable primary inputs when countries engage in asymmetric trade. We obtain explicit links between persistent gaps in productivity growth and the incentives of resource-exporting (importing) countries to subsidize (tax) domestic resource use. The exporters' incentive to subsidize hinges on slower productivity growth and is disconnected from the importers' incentive to tax resource inflows—i.e., rent extraction. Moreover, faster productivity growth exacerbates the importers' incentive to tax, beyond the rent-extraction motive. In a strategic tax game, the only equilibrium is of Stackelberg type and features, for a wide range of parameter values, positive exporters' subsidies and positive importers' taxes at the same time.

In this paper, we study the positive and normative implications of financial shocks in a standard New Keynesian model that includes banks and frictions in the market for bank capital. We show how such frictions influence materially the effects of bank liquidity shocks and the properties of optimal policy. In particular, they limit the scope for countercyclical monetary policy in the face of these shocks. A fiscal policy instrument can complement monetary policy by offsetting the balance-sheet effects of these shocks, and jointly optimal policies attain the same equilibrium that monetary policy (alone) could attain in the absence of equity-market frictions.