The Persistence of Profits in the Long Run: A New Approach

We present a trend-based alternative to the standard first-order autoregression model in persistence of profits studies. This is motivated by reservations over the interpretation of the standard model, and rests on a different concept of dynamic competition. A nine-category taxonomy of long-run persistence stereotypes is developed. Structural time series estimates are presented for a sample of UK companies. We find the null of long run competitive equilibrium not rejected in nearly a third of cases, but non-eroding persistence to be present in around 60%.