Juan Carlos Cordoba

A GENERALIZED GIBRAT'S LAW*

Many economic and non-economic variables such as income, wealth, firm size, or city size often distribute Pareto in the upper tail. It is well established that Gibrats law can explain this phenomenon, but Gibrats law often does not hold. This note characterizes a class of processes, one that includes Gibrats law as a special case, that can explain Pareto distributions. Of particular importance is a parsimonious generalization of Gibrats law that allows size to affect the variance of the growth process but not its mean. This note also shows that under plausible conditions Zipfs law is equivalent to Gibrats law. Copyright

COLLATERAL CONSTRAINTS IN A MONETARY ECONOMY

The purpose of this paper is to analyze the role of collateral constraints as a transmission mechanism of monetary shocks. We do this by introducing money in the heterogeneous-agent real economy of Kiyotaki and Moore (1997). Money enters in a cash-in-advance constraint and is injected via open-market operations. In the model, a one-time exogenous monetary shock generates persistent movements in aggregate output, whose amplitude depends on the degree of debt indexation. Monetary expansions can trigger a large upward movement in output, while monetary contractions give rise to a smaller downward movement. This asymmetry occurs because full indexation of debt contracts can only be effective following a monetary contraction. In contrast, following a monetary expansion indexation can only be partial because debtors end up paying back just the market value of the collateral. Due to the existence of both cash-in-advance and collateral constraints, monetary shocks generate a highly persistent dampening cycle rather than a smoothly declining deviation.

Intergenerational Transfers and the Fertility–Income Relationship

Evidence from cross‐sectional data reveals a negative relationship between family income and fertility. This article argues that constraints to intergenerational transfers are crucial for understanding this relationship. If parents could legally impose debt obligations on their children to recover the costs incurred in raising them, then fertility would be independent of parental income. A relationship between fertility and income arises when parents are unable to leave debts because of legal, enforcement or moral constraints. This relationship is negative when the intergenerational elasticity of substitution is larger than one, a case in which parental consumption is a good substitute for childrens consumption.

Supply Side Structural Change

The interest rate and the rate of economic growth are often regarded as roughly constant as economies grow. Moreover, the share of agriculture in production and the share of rural population typically shrink. We show that an otherwise standard growth model that includes a backward and an advanced sector can account for these regularities. The mechanism works as follows: as the economy accumulates capital, labor flows from the backward sector to the advanced one. This migration prevents the usual diminishing marginal returns of capital. As a result, the interest rate and the growth rate of the economy remain constant during the transition to the steady state.