We characterize optimal product market policy in an unequal economy in which firm ownership is concentrated and markups increase with firm market shares. We study the problem of a utilitarian regulator who designs revenue-neutral interventions in the product market. We show that optimal policy increases product market concentration. This is because policies that encourage larger producers to expand improve allocative efficiency, increase the demand for labour and equilibrium wages. We derive these results both in a static Mirrleesian setting in which we impose no constraints on the shape of interventions, as well as in a dynamic economy with wealth accumulation. In our dynamic economy optimal policy reduces wealth and income inequality by redistributing market share and profits from medium-sized businesses, which are primarily owned by relatively rich entrepreneurs, to larger diversified corporate firms.

Many households hold little wealth. In standard precautionary savings models, these households should not only display higher marginal propensities to consume (MPCs) but also higher future consumption growth. In contrast, we see from the Panel Study of Income Dynamics that such “hand-to-mouth” households do not display higher growth in spending. They also exhibit greater volatility of spending and adjust their spending to a greater extent through the number of categories consumed. Consistent with a role for preference heterogeneity, the panel data show that it is persistent differences across households, not current assets, that predict low consumption growth and other spending differences for the hand-to-mouth households. To identify the extent of preference heterogeneity, we consider the model of Kaplan and Violante with both liquid and illiquid assets, but allow heterogeneity in preferences. To match the data, many poor hand-to-mouth must be relatively impatient and have a high inter-temporal elasticity of substitution. The model shows that preferences predominantly explain the higher MPCs for low-asset households. Preference heterogeneity notably increases the spending impact of fiscal transfers, but only if targeted, while reducing that from interest rate cuts.