The power of financial accounting to shape corporate behavior is underappreciated. Advocates of positive accounting theory have argued that even cosmetic changes in reported earnings can affect share value, not because market participants are unable to see through such changes to the underlying fundamentals, but because of implicit or explicit contracts that are based on reported earnings and transaction costs. However, agency theory suggests that accounting choices and corporate responses to accounting standard changes will not necessarily be those that maximize share value. For a number of reasons, including the fact that executive compensation is often tied to reported earnings, managerial preferences for high earnings generally will exceed shareholder preferences, leading to share value reducing tradeoffs between reported earnings and net cash flows. Empirical evidence supporting the detailed predictions of these theories is mixed, but the evidence firmly establishes the power of accounting to shape corporate behavior. The power of accounting and the divergence of interests have many implications for courts and policy makers. For example, consideration of proposals to increase conformity between tax an d financial accounting rules as a means of combating tax sheltering and/or artificial earnings inflation must take into account the incentive properties of accounting standards and recognize that narrowing the gap between tax and book income will have economic consequences however the gap is narrowed This Article considers this and other implications of the behavioral effects of accounting standards, including the possibility of setting accounting standards instrumentally as a means of regulating corporate behavior, an alternative to tax incentives, mandates, or direct subsidies.