We analyze entry, pricing, and product design in a model with differentiated products. Market equilibrium can be “separating,” with multiple sellers and a sorting of heterogeneous consumers across goods, or “exclusionary,” with one seller serving all customer types. Entry into an initially monopolized market can occur because of cost reductions or product improvements, but entry need not lower the incumbent’s price, improve efficiency, or raise consumer welfare. Postentry design incentives favor a softening of price competition and stronger market segmentation, whereas exclusionary design changes typically raise consumer welfare. Potential, as distinct from actual, entry always benefits consumers.

We study the link between market forces, cross-sectional inequality, and intergenerational mobility. Emphasizing complementarities in the production of human capital, we show that wealthy parents invest, on average, more in their offspring than poorer ones. As a result, economic status persists across generations even in a world with perfect capital markets and without differences in innate ability. In fact, under certain conditions, successive generations of the same family may cease to regress toward the mean. We also consider how short- and long-run mobility are affected by changes in the returns to human capital.