This paper introduces an internal capital market into a two-factor model of multi-segment firms. It features empire building by managers and informational frictions within the organization. The headquarters knows less about a segment’s true cost than its divisional managers do, so managers can over-report their costs and receive more capital than optimal. Our novel theory, which enables us to endogenize the cost structure of multi-segment firms, shows that international trade imposes discipline on divisional managers and improves the capital allocation between divisions, thereby lowering the conglomerate discount. The theory can explain why exporters exhibit a lower conglomerate discount than non-exporters. We exploit the China shock as an exogenous change to competition to confirm the model’s predictions with data on US companies.