Abstract:We survey companies and find that many use incorrect tax rate inputs into important corporate decisions. Specifically, many companies use an average tax rate (the GAAP effective tax rate, ETR) to evaluate incremental decisions, rather than using the theoretically correct marginal tax rate. We find evidence consistent with behavioral biases (heuristics, salience) and managers' educational backgrounds affecting these choices. We estimate the economic consequences of using the theoretically incorrect tax rate and find that using the ETR for capital structure decisions leads to suboptimal leverage choices and using the ETR in investment decisions makes firms less responsive to investment opportunities. This paper is the winner of the American Accounting Association 2015 FARS Midyear Meeting Best Paper Award. We thank John Barrios for sharing data on the LinkedIn profiles of our survey respondents. We appreciate helpful comments from Robin Greenwood (the editor), two anonymous referees, Mary Barth, James Chyz, Bryan Cloyd, Russ Lundholm, Lil Mills (discussant), Richard Sansing, Joel Slemrod (discussant), seminar participants at the Baruch College, Columbia Law School, INSEAD conference, International Institute for Public Finance (IIPF) Annual Congress (Dublin), MaTax Conference in Germany, Stanford Summer Camp, University of California, Davis, University of Tennessee, and Virginia Tech University. Thanks to the following people for helpful comments on the development of survey questions: Jennifer Blouin, Merle Erickson, Ken Klassen, Ed Maydew, Peter Merrill, Lil Mills, Sonja Rego, Richard Sansing, Stephanie Sikes, Joel Slemrod, and Ryan Wilson. We also appreciate the support of PricewaterhouseCoopers (especially Peter Merrill) and the Tax Executives Institute (especially Tim McCormally) in asking firms to participate and in reviewing the survey document. We are grateful for the discussions with several tax executives about their role in their company. Finally, each author is grateful for the financial support of the Fuqua School of Business, Paton Accounting Fund at the University of Michigan, MIT Junior Faculty Research Assistance Program, and the Paul Merage School of Business at the University of California-Irvine. All errors are our own.
1Taxes represent a significant cost for most profitable corporations and, thus, are an important input into many corporate decisions (see Shackelford and Shevlin (2001), Graham (2003), and Hanlon and Heitzman (2010) for reviews). According to theory, the marginal tax rate (MTR), defined as the present value of additional taxes paid on an additional dollar of income earned today (Scholes et al., 2014), is the appropriate rate to use to evaluate incremental corporate decisions (MacKie-Mason, 1990; Graham, 1996a, b;Brealey, Myers, and Allen, 2014;and Scholes et al., 2014). Consistent with this theory, prior research finds that the MTR is correlated with firms' capital structure decisions (e.g., Graham, 1996a;Heider and Ljungqvist, 2015). However, prior research also finds...