Market concentration ratios are popular statistics for characterizing the extent of marketdominance in an imperfectly competitive market, but these ratios may not agree whencomparing two markets. Neither do they necessarily agree with the Herfindahl-Hirschman orentropy indices. This letter...

Our context involves Cournot oligopolists producing NM products at constant marginal costs when preferences are quasi-linear. We identify relationships between second moments of unit costs and second moments of firm-level production. For example, a larger variance in unit costs of a product...