We present a model with firms selling (homogeneous) products in two imperfectly segmented markets (a "high-demand" and a "low-demand" market). Buyers are mobile but restricted by transportation costs, so that imperfect arbitrage occurs when prices differ in both markets. We show that equilibria...

We analyze the efficiency defense in merger control. First, we show that the relationship between exogenous efficiency gains and social welfare can be non-monotone. Second, we consider both endogenous mergers and endogenous efficiencies and find that merger proposals are largely aligned with a...

We analyze how consumer preferences for one-stop shopping affect the bargaining relationship between a retailer and its suppliers. One-stop shopping preferences create "demand complementarities" among otherwise independent products which lead to two opposing effects on upstream merger...