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...

This paper is motivated by the empirical regularity that industries differ greatly in the level of firm turnover, and that entry and exit rates are positively correlated across industries. Our objective is to investigate the effect of sunk costs and, in particular, market size on entry and exit...

This Paper develops a model of endogenous product selection by firms. The theory is motivated by new evidence we present on the importance of product switching by US manufacturers. Two-thirds of continuing firms change their product mix every five years, and product switches involve more than...

This paper studies the extensive and intensive margins of firms' global sourcing decisions. We develop a quantifiable multi-country sourcing model in which heterogeneous firms self-select into importing based on their productivity and country-specific variables. The model delivers a simple...

Researchers typically invoke theoretical assumptions to estimate mark-ups. Instead, we directly obtain mark-ups by surveying Pakistani soccer-ball producers. We document six facts: (1) Mark-ups are more dispersed than costs; (2) Mark-ups and costs increase with firm size; (3) The mark-up...

This paper provides evidence that learning about demand is an important driver of firms' dynamics. We present a simple model with Bayesian learning in which firms are uncertain about their idiosyncratic demand parameter in each of the markets they serve, and update their beliefs as noisy...

Preventives are sold ex ante, before disease status is realized, while treatments are sold ex post. Even if the mean of the ex ante distribution of consumer values is the same as that ex post, the shape of the distributions may differ, generating a difference between the surplus each product can...

We present evidence from 260,000 online auctions of second-hand cars to identify the impact of public reserve prices on auction outcomes. We exploit multiple discontinuities in the relationship between reserve prices and vehicle characteristics to present causal RD estimates of reserve price...

Reduced form approaches to estimate markups typically exploit variation in observed input and output. However, these approaches ignore the presence of fixed input factors, which may result in an overestimation of the price-cost margins. We first propose a new methodology to simultaneously...