Pairwise trade and coexistence of money and higher-return assets

A new theory of coexistence of money and higher-return assets is set out. It applies to any setting in which some trade involves an exchange of goods for assets and occurs between two people—a buyer and a seller. We show that there exists a function mapping the portfolios of the buyer and the seller to the trade that occurs such that (i) the trade is in the buyer–seller core and (ii) some people are induced to enter the buyer–seller meeting with money.