Competitive Cross-Subsidization

This paper analyzes competitive pricing policies by multiproduct firms facing heterogeneous buying patterns. We show that cross-subsidization arises when firms have comparative advantages on different products but are equally efficient overall: Firms earn a profit from multi-stop shoppers by charging positive margins on their strong products but, as price competition for one-stop shoppers drives total margins down to zero, they price weaker products below cost. Banning below-cost pricing leads to higher profits and higher prices for one-stop shoppers, and may reduce consumer surplus as well as total social welfare.