Persistence in Corporate Performance? Empirical Evidence from Panel Unit Root Tests

Persistence in corporate performance is analyzed in the framework of empirical tests of unit root behavior concerning firm profits. Data for firm-specific rates of return is applied in a set of panel unit root tests to address the question of persistence in profits both at firm level and for the aggregate level of industry-specific profits. The firm data all reject a null hypothesis of random walk behavior of profits but when smoothing profit rates at a two-digit NACE-code level for industries, the empirical evidence is more mixed as most industries show up with a unit root in aggregate rates of return, i.e. indicating persistence in corporate performance. [PUBLICATION ABSTRACT]