Abstract
The Coasean theory of the firm (Coase in Economica 4:386–405, 1937) has flourished with the theory of incomplete contracts. Transaction costs in the form of enforcement costs have been deemed to be the main determinants of the decision to ‘make’ versus ‘buy’. Surprisingly, this stream of literature has almost neglected that transaction costs may also generate incomplete property rights (Coase in J Law Econ 3:1–44, 1960). As firm’s activities entail both contractual and property rights, these two domains interfere each other on the decision to carry out a transaction within the firm. When property rights are incomplete, potential externalities may increase the cost of using the price mechanism to procure the assets needed in a given transaction. The resulting ‘Coasean firm’ would not only centralize incom- plete contracts under a unified governance system, but it will also aggregate incomplete property rights under a unified ownership structure.