The Action Theory of Exchanges is based on three main assumptions: i) an exchange is motivated by people having convergent preferences, ii) people exchange actions, and iii) offers and acceptances are crucial parts of an exchange and they bring about rights and obligations. The main aim of this paper is to discuss three aspects of this theory to better understand its ontological implications and, possibly, improve it. I first examine the expression “transferring the ownership” by showing an ontological issue behind (...) it; after that, I propose an interpretation that might solve this issue. I then show that convergent preferences are not enough to motivate an exchange; accordingly, one has to introduce two more preferences possessed by the agents. I finally propose a characterization of buying and selling (and buyer and seller) which, in addition to being compatible with the Action Theory of Exchanges, has the advantage of accounting for both monetary and non-monetary exchanges. (shrink)