In an economy with complete markets, the owners of a firm will unanimously desire the firm to maximize profits if it is a perfect competitor. We generalize this result to an economy with incomplete markets. We show that if competitive conditions prevail--that is, if each firm is negligible relative to the aggregate economy--a firm's shareholders will want the firm to maximize the (net) market value of its shares. This result holds whether or not the so-called spanning condition is satisfied. However, while there may be agreementabout what goal the firm should pursue, there may be disagreement among shareholders about how best to pursue this goal.