Before revision:  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:  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 , and that it can instead be true if one restricts to the endowments in the interior. We show however how the endowments on the boundary can give rise to very odd phenomena; for example, an investor with such an endowment would choose not to trade in the derivative even at prices arbitrarily close to some arbitrage price .