Testing Gibrat's law in Italian macro-regions: Analysis on a panel of mechanical companies

The present paper deals with the question whether "Gibrat's law" is applicable to Italian mechanical companies active between 1997 and 1999 or not. The analysis was carried out at a spatial level splitting companies in four macro-regions: North-West, North-East, Centre and South. On the basis of a set of descriptive and inferential tools, we find that firm size, measured by total assets, follows approximately a log-normal distribution in at least two of the four analyzed macro-regions. Nevertheless log-normality is only one necessary but not sufficient condition for the validity of the Gibrat's law. Thus we analyzed the influence of firm size on growth rate finding a negative relation between the two variables in all macro-regions. This is a clear violation of Gibrat's law. Another violation was found by the application of an econometric model which evidences the persistence of growth. © Springer-Verlag 2005.