The Coase theorem on social cost
With clear property rights and zero bargaining costs, parties negotiate efficient outcomes regardless of who holds the right. Externalities become a problem of transaction costs.
The firm, the market, and the law
7 ideas
Economics grounded in real institutions
Coase insists on studying how firms, contracts, and law actually operate, not idealized models. Institutional friction is central, not incidental.
Sturges v. Bridgman: confectioner versus doctor
In this 1879 English case, a confectioner had used noisy mortars and pestles for years. A doctor then built a consulting room against the confectioner's wall and found the noise made it unusable, and the court granted him an injunction. Coase showed that if bargaining were costless, the outcome would not depend on the ruling. Either the confectioner would pay the doctor to tolerate the noise, or the doctor would pay the confectioner to stop, depending on which use was worth more. The court decided only who paid whom.
The margin that sets firm boundaries
A firm expands until the cost of organizing one more transaction inside it equals the cost of carrying out that transaction on the open market, or the cost of having another firm organize it. Organizing costs rise with size, as managerial mistakes pile up and resources are misallocated. Anything that lowers internal coordination costs, such as better communication technology, makes firms larger. Anything that lowers market transaction costs makes them smaller.
Harm is reciprocal, not one-sided
When one party's activity harms another, stopping A from harming B inflicts harm on A. The real question is which harm is worse, not who is at fault. Reframing a nuisance this way shifts the analysis from assigning blame to comparing the total value produced under each alternative arrangement.
When bargaining is costly, rights allocation decides outcomes
If transactions were costless, parties would bargain to the most valuable use of a resource no matter how the law assigned rights. Real transaction costs often exceed the gains from renegotiating, so the initial assignment of rights sticks and shapes what actually gets produced.
Firms exist because markets cost money
Using the price mechanism has costs: finding counterparties, discovering relevant prices, and negotiating and enforcing a separate contract for every exchange. A firm replaces many such contracts with one employment relation in which an entrepreneur directs resources by command. The firm therefore exists where coordinating by authority is cheaper than coordinating by repeated market transactions.