A Note on Instability and Indeterminacy in Search and Matching Models

We demonstrate the possibility of indeterminacy and non-existence of equilibrium dynamics in a standard business cycle model with search and matching frictions in the labor market. Our results arise for empirically plausible parametrizations and do not rely upon a mechanism such as increasing returns.

Theoretical Foundations of Buffer Stock Saving

"Buffer-stock" versions of the dynamic stochastic optimizing model of saving are now standard in the consumption literature. This paper builds theoretical foundations for rigorous understanding of the main characteristics of buffer stock models, including the existence of a target level of wealth and the proposition that aggregate consumption growth equals aggregate income growth in a small open economy populated by buffer stock consumers.

Some Foundations for Multiplicative Habits Models

While consumption models with multiplicative habits are becoming increasingly popular, some important theoretical questions about these models have not yet been addressed. This paper fills three such gaps: Existence of an optimal consumption path; satisfaction, by that path, of the consumption Euler equation; and convergence of that path to the stationary (steady state) path.

Cartel Pricing Dynamics with Cost Variability and Endogenous Buyer Detection

This paper characterizes collusive pricing patterns when buyers may detect the presence of a cartel. Buyers are assumed to become suspicious when observed prices are anomalous. We find that the cartel price path is comprised of two phases. During the transitional phase, price is generally rising and relatively unresponsive to cost shocks. During the stationary phase, price responds to cost but is much less sensitive than under non-collusion or simple monopoly. The length of the transition phase is decreasing in the variance of cost shocks. It is also shown that the cartel price path may overshoot its long-run level so that price converges from above.

On-the-Job Search and the Cyclical Dynamics of the Labor Market

We develop a dynamic general equilibrium model where workers can engage in search while on the job. We show that on-the-job search is a key component in explaining labor market dynamics in models of equilibrium unemployment. The model predicts fluctuations of unemployment, vacancies, and labor productivity whose relative magnitudes replicate the data. A standard search and matching model suggests much lower volatitilities of these variables. Intuitively, in a boom, rising search activity on the job avoids excessive tightening of the labor market for expanding firms. This keeps wage pressures low, thus further increasing firms’ incentives to post new jobs. Labor market tightness as measured by the vacancy-unemployment ratio is as volatile as in the data. The interaction between on-the-job search and job creation also generates a strong internal propagation mechanism.

The Interest Rate, Learning, and Inventory Investment

Economic theory predicts a negative relationship between inventories and the real interest rate, but previous empirical studies (mostly based on the older stock adjustment model) have found little evidence of such a relationship. We derive parametric tests for the role of the interest rate in specifications based on the firm’s optimization problem. These Euler equation and decision rule tests mirror earlier evidence, finding little role for the interest rate. We present a simple and intuitively appealing explanation, based on regime switching in the real interest rate and learning, of why tests based on the stock adjustment model, the Euler equation, and the decision rule – all of which emphasize short-run fluctuations in inventories and the interest rate – are unlikely to uncover a relationship. Our analysis suggests that inventories will not respond much to short-run fluctuations in the interest rate, but they should respond to long-run movements (regime shifts; e.g., between low real rates in the 1970s and high rates in the early 1980s). Both simple and sophisticated tests confirm our predictions and show a highly significant long-run relationship between inventories and the interest rate, with an elasticity of about -1.5. Furthermore, a formal model of our explanation yields a distinctive, testable implication. This implication is supported by the data.

Monetary Policy and the Dangers of Deflation: Lessons from Japan

This paper investigates how monetary policy can help to avoid the liquidity trap by studying the experience of Japan. First, I analyze how the Bank of Japan conducted interest rate policy over the 1990s as the economy entered a deflationary slump. I use a new method of estimating the policy rule with a time-varying inflation target and a time-varying natural rate of interest. The estimation strategy reveals that the Bank’s implicit inflation target declined to about 1% in the 1990s from about 2.5% in the 1980s. I also find that the policy rule respects the Taylor principle and is forward looking. Such a Taylor rule does not depart from what was perceived as current best practice. It thus seems that the problem arose because of a series of adverse shocks and not because of an extraordinary monetary policy mistake. Next, I investigate whether an alternative monetary policy rule could have avoided the liquidity trap despite these shocks. I find that targeting a higher rate of inflation of 2-3% would not have provided much protection against hitting the zero bound on nominal interest rates. Similarly, a policy of responding more aggressively to the inflation gap while keeping the low inflation target would have provided little improvement in economic performance. The economy also still enters the trap under a nonlinear policy rule that commits the central bank to keeping interest rates at zero even after the economy begins to recover. However, I find that a rule that combined both (i) a higher inflation target of about 3%, and (ii) a more aggressive response to the inflation gap would have improved the economy’s performance and avoided the zero bound.

Collusion under Monitoring of Sales

Collusion under imperfect monitoring is explored when firms’ prices are private information and their quantities are public information; an information structure consistent with several recent price-fixing cartels such as those in lysine and vitamins. For a class of symmetric duopoly games, it is shown that symmetric equilibrium punishments cannot sustain any collusion. An asymmetric punishment is characterized which does sustain collusion and it has the firm with sales exceeding its quota compensating the firm with sales below its quota. In practice, cartels have performed such transfers through sales among the cartel members.

Disinflations in Latin America and the Caribbean: A Free Lunch?

This paper challenges the conventional view according to which disinflations in LAC-even from low and moderate peaks-have been carried out at no cost to output. After suggesting a new methodology that allows for long-lived effects and inflation inertia when measuring costs of disinflations, large sacrifice ratios are obtained for the 1970s and 80s. Nevertheless, a new puzzle arises: disinflation costs in the 90s are negative, even with the new methodology. It is shown that an unusual combination of circumstances-i.e. capital inflows, structural reforms and the peculiar recent inflation history-can explain that fortunate result. Moreover, it is shown that LAC episodes exhibit a larger speed than G7 experiences. That speed differential explains why disinflation costs in developed nations are on average larger than LAC’s.