Barriers to entry are regarded as major impediments to the working of markets. Entry must not necessarily actually take place - the perceived threat of entry may encourage incumbent firms to behave as if they are in a competitive market, even if they are not. We present empirical evidence on...

Theory predicts a positive relationship between market concentration and profitability in most scenarios. In empirical work, however, this relation is frequently not found or only a weak connection is observed. We compare the performance of concentration and market share variables, which are...