This paper provides a framework for addressing the question of when transactions should be carried out within a firm and when through the market. Following Grossman and Hart, we identify a firm with the assets that its owners control. We argue that the crucial difference for party 1 between owning a firm (integration) and contracting for a service from another party 2 who owns this firm (nonintegration) is that, under integration, party 1 can selectively fire the workers of the firm (including party 2), whereas under nonintegration he can "fire" (i.e., stop dealing with) only the entire firm: the combination of party 2, the workers, and the firm's assets. We use this idea to study how changes in ownership affect the incentives of employees as well as those of owner-managers. Our framework is broad enough to encompass more general control structures than simple ownership: for example, partnerships and worker and consumer cooperatives all emerge as speical cases.

It is sometimes asserted that rational speculative activity must result in more stable prices because speculators buy when prices are low and sell when they are high. This is incorrect. Speculators buy when the chances of price appreciation are high, selling when the chances are low. Speculative activity in an economy in which all agents are rational, have identical priors, and have access to identical information may destabilize prices, under any reasonable definition of destabilization. It takes extremely strong conditions to ensure that speculative activity (of the commodity storage variety) "stabilizes" price, even in a very weak sense.

Our theory of costly contracts emphasizes the contractual rights can by of two types: specific rights and residual rights. When it is costly to list all specific rights over assets in the contract, it may be optimal to let one party purchase all residual rights. Ownership is the purchase of these residual rights. When residual rights are purchased by one party, they are lost by a second party, and this inevitably creates distortions. Firm 1 purchases firm 2 when firm 1's control increases the productivity of its management more than the loss of control decreases the productivity of firm 2's management.

We consider an economy that has to decide how assets are to be used. Agents have ideas, but these ideas conflict. We suppose that decision‐making authority is determined by hierarchy: each asset has a chain of command, and the most senior person with an idea exercises authority. We analyze the optimal hierarchical structure given that some agents coordinate and other specialize. Among other things, our theory explains why coordinators should typically be senior to specialists and why pyramidal hierarchies may be optimal. Our theory also throws light on the optimal degree of decentralization inside a firm and on firm boundaries.

This paper provides a framework for addressing the question of when transactions should be carried out within a firm and when through the market. Following Grossman and Hart, we identify a firm with the assets that its owners control. We argue that the crucial difference for party 1 between owning a firm (integration) and contracting for a service from another party 2 who owns this firm (nonintegration) is that, under integration, party 1 can selectively fire the workers of the firm (including party 2), whereas under nonintegration he can "fire" (i.e., stop dealing with) only the entire firm: the combination of party 2, the workers, and the firm's assets. We use this idea to study how changes in ownership affect the incentives of employees as well as those of owner-managers.

A general equilibrium model of optimal employment contracts is developed where firms have better information about labor's marginal product than workers. It is optimal for the wage to be tied to the level of employment, to prevent the firm from falsely stating that the marginal product is low and cutting the wage. It is shown that an observed aggregate shock that leads to an interindustry shift in labor demand and that would have no effect on total employment under symmetric information leads to a reduction in employment when firms and workers have asymmetric information.

Our theory of costly contracts emphasizes that contractual rights can be of two types: specific rights and residual rights. When it is costly to list all specific rights over assets in the contract, it may be optimal to let one party purchase all residual rights. Ownership is the purchase of these residual rights. When residual rights are purchased by one party, they are lost by a second party, and this inevitably creates distortions. Firm 1 purchases firm 2 when firm 1's control increases the productivity of its management more than the loss of control decreases the productivity of firm 2's management.

A general equilibrium model of optimal employment contracts is developed where firms have better information about labor's marginal product than workers. It is optimal for the wage to be tied to the level of employment, to prevent the firm from falsely stating that the marginal product is low and cutting the wage. It is shown that an observed aggregate shock that leads to an interindustry shift in labor demand and that would have no effect on total employment under symmetric information leads to a reduction in employment when firms and workers have asymmetric information.

It is sometimes asserted that rational speculative activity must result in more stable prices because speculators buy when prices are low and sell when they are high. This is incorrect. Speculators buy when the chances of price appreciation are high, selling when the chances are low. Speculative activity in an economy in which all agents are rational, have identical priors, and have access to identical information may destabilize prices, under any reasonable definition of destabilization. It takes extremely strong conditions to ensure that speculative activity (of the commodity storage variety) "stabilizes" price, even in a very weak sense.

Insolvency practitioners from 88 countries describe how debt enforcement will proceed against an identical hotel about to default on its debt. We use the data on time, cost, and the likely disposition of the assets (preservation as a going concern vs. piecemeal sale) to construct a measure of the efficiency of debt enforcement in each country. This measure is strongly correlated with per capita income and legal origin and predicts debt market development. Several characteristics of debt enforcement procedures, such as the structure of appeals and availability of floating charge finance, influence efficiency.