The Coase theorem, developed by Ronald Coase and labeled as such by George Stigler, states that private transactions are efficient as long as property rights exist, only a small number of parties are involved, and transactions costs are low. Additionally, this efficiency will take place regardless of who owns the property rights. This theory comes from a section of Coase's Nobel prize-winning work "The Problem of Social Cost". While the assumptions of low transactions costs and a small number of parties involved may not always be applicable in real-world markets, Coase's work changed the long-held belief that the owner of property rights was a major determining factor in whether or not a market would fail. The Coase theorem points out when one would expect the market to function properly even when there are externalities.