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.