Who really matters in corporate tax?

Internal and external parties meaningfully shape corporate tax outcomes. However, we lack a holistic understanding of the major parties involved and their comparative effects. Using proprietary IRS data for public and private firms, we identify the top executives, corporate accountants, external accounting firms, and individual tax preparers and examine the comparative importance of these parties on corporate tax outcomes. We find that external individual tax preparers matter much more than the accounting firms that employ them. Internal actors (top accountants and executives) explain more of the variation in corporate tax outcomes than external actors (individual tax preparers and accounting firms). We also find some evidence that individuals’ characteristics are associated with the tax behavior of the corporations they serve. Overall, we conclude that some of the actors who are unobservable in public data play a greater role in corporate tax outcomes than parties that are a focus of prior research.