Market Size, Entrepreneurship, and Income Inequality

We develop a monopolistic competition model with two sectors and heterogeneous agents who self-select into entrepreneurship, depending on entrepreneurial ability. The effect of market size on the equilibrium share of entrepreneurs crucially hinges on properties of the lower-tier utility function for differentiated varieties – its elasticity of substitution and its Arrow-Pratt index of relative risk aversion. We show that the share of entrepreneurs, and the cutoff for self-selection into entrepreneurship, can increase or decrease with market size. The properties of the underlying ability distribution largely determine how income inequality changes with market size.