What turns the taxman on? Audit opinion and tax return adjustments in a voluntary audit environment

Abstract

Using a large proprietary data set obtained from the Finnish Tax Administration, we examine the factors that trigger adjustments by the tax authority to the taxable income reported by around 25,000 small private companies in their tax returns. After controlling for tax aggressiveness and other relevant factors, we find that having a voluntary audit with an unqualified audit opinion decreases the likelihood of the tax authority not accepting taxable income as reported. At the same time, it moderates the otherwise significant positive effect of tax aggressiveness on the likelihood of tax authority making adjustments.