Coase theorem a non-formal insight by Ronald Coase (Nobel Prize in Economics, 1991): assuming that there are no (transaction) costs involved in exchanging rights for money, then no matter how rights are initially distributed, rational agents will buy and sell them so as to maximize individual returns. In jurisprudence this proposition has been the basis for a claim about how rights should be distributed even when (as is usual) transaction costs are high: the law should confer rights on those who would purchase them were they for sale on markets without transaction costs; e.g., the right to an indivisible, unsharable resource should be conferred on the agent willing to pay the highest price for it. See also PHILOSOPHY OF ECONOMIC. A.R.