Incomplete Contracts and the Theory of the Firm: What Have We Learned over the Past 25 Years?

Sanford Grossman and Oliver Hart used the theory of incomplete contracts to develop answers to the question "What is a firm, and what determines its boundaries?" in their path-breaking paper on "The Costs and Benefits of Ownership: A Theory of Vertical and Lateral Integration" (<em>Journal of Political Economy</em>, 1986, vol. 94, no. 4). Perhaps the central issue is that economic actors are only boundedly rational and cannot anticipate all possible contingencies. It might well be that certain states of nature or actions cannot be verified by third parties after they arise, like certain qualities of a good to be traded in the future, and thus cannot be written into an enforceable contract. When contracts are incomplete, and consequently not all uses of an asset can be specified in advance, any contract negotiated in advance must leave some discretion over the use of the assets; and the "owner" of the firm is the party to whom the residual rights of control have been allocated at the contracting stage. The optimal allocation of property rights—or governance structure—is one that minimizes efficiency losses. This produces a theory of ownership and vertical integration as well as a theory of the firm. First we spell out Grossman and Hart's argument using a simple numerical example. Then we show how the incomplete contracts approach can be used to analyze the firms' internal organization; the firms' financial decisions; the costs and benefits from privatization; and the organization of international trade between inter- and intrafirm trade. We discuss several criticisms of the incomplete contracts/property rights methodology and review recent developments of the incomplete contracts approach.