Are Multinational Corporate Tax Rules as Important as Tax Rates?

Previous research has documented the influence of statutory tax rates on international firms' effective tax rates, or ETRs. We add to this body of research by examining common factors of the income tax base, which affects ETRs. Specifically, this study examines the determinants of effective tax rates for publicly traded companies based in European Union (EU) countries. The time period examined is after 2004, when all EU firms were required to use standardized accounting principles under International Financial Reporting Standards (IFRS). We find that, across EU countries, such factors are relatively consistent with factors found in studies of U.S. companies' effective tax rates, which include inventory, leverage, depreciation tax shield, and R&D intensity. We also find that the presence of country book-tax conformity rules increases effective rates. Importantly, our finding that such tax base (or rule) effects are at least as important as rate effects adds to the international debate about uneven tax structures around the globe.