The Optimal Relationship Between Taxable Income and Financial Accounting Income: Analysis and a Proposal

Abstract

The persistence of the book-tax gap, or excess of companies' reported financial accounting income over their taxable income, suggests that accounting manipulation and tax sheltering remain significant problems, even in the aftermath of the "Enron era." Some have therefore suggested making the United States a "one-book" country, in which the same income measure would be used for both purposes. This Article offers the first systematic exploration of the optimal relationship between the two income measures, based on the distinct purposes they serve and the significance of two distinct sets of incentive problems: those pertaining to corporate managers, and to the political decisionmakers who make the rules. Absent these incentive problems, the two ideal measures would differ, reflecting that allocating tax burdens is not the same exercise as informing investors. The incentive problems cut in favor of uniformity, however, by supporting the creation of a "Madisonian" offset between managers' and politicians' twin quests for high accounting income and low taxable income. But this offset has more promise as a device to constrain managers than politicians, given the difficulty of binding Congress and the existing partial insulation of accounting rules from direct political influence. In light of the political incentive issues, pure one-book and two-book approaches may both be inferior to partial conformity, such as that which would result from generally requiring a 50 percent adjustment by large, publicly traded companies of taxable income towards financial accounting income.