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.