Before revision: In this paper we ask whether  arbitrage-free prices are obtained by utility maximization. This is found to be true for any given investor , provided that one considers the marginal utility-based prices relative to all initial endowments with finite utility  .
After revision: In this paper we ask whether arbitrage-free prices at which an utility-maximizing agent would always want to buy the derivative, irrespectively of his own initial endowment of derivatives and cash. We prove that this is false for any given investor , provided that one considers the marginal utility-based prices relative to all initial endowments with finite utility .