Abstract

Prior research concludes that tax-expert auditors facilitate tax aggressiveness. However, these studies examine auditors who also provide non-audit tax services to their clients, creating conflicting incentives. We predict that tax-expert auditors, who do not provide non-audit tax services, reduce tax aggressiveness, because tax aggressiveness imposes costs on them. We test our prediction using Chinese data, allowing us to identify Certified Tax Agents as tax-expert auditors. We find that companies are less tax aggressive when their signatory auditor is a tax-expert who does not provide non-audit tax services. Consistent with a causal relation, a decrease in tax rates, which reduces clients’ incentives to be tax aggressive, weakens the effect of tax-expertise on tax aggressiveness. Moreover, tax-expert auditors attenuate the type of tax aggressiveness that results in tax-related misstatements. Overall, by examining auditors who do not provide non-audit tax services, we find that tax-expert auditors curb tax aggressiveness, contrary to prior research.

Introduction

Prior research finds that some potential monitors of tax aggressiveness, including tax-expert auditors, facilitate aggressive tax avoidance ( Bianchi et al., 2019 ; McGuire et al., 2012 ). These studies, however, examine auditors who also provide non-audit tax services to their clients. Performing both audit and non-audit tax services creates conflicting incentives for auditors, making it difficult to interpret their results. As providers of assurance services, auditors have incentives to reduce clients’ tax aggressiveness, because tax aggressiveness increases the risk of adverse outcomes that impose costs on auditors. As providers of non-audit tax services, auditors have incentives to act as advocates for clients’ aggressive tax positions. The purpose of this study is to examine whether signatory auditors with tax expertise, who only perform audit services, curb tax aggressiveness.

Signatory auditors have incentives to curb tax aggressiveness because it is associated with adverse outcomes, including earnings management, fraud, scrutiny from regulators, poor earnings quality, audits by tax authorities, financial reporting opacity and misstatements, and higher crash risk. 1 These adverse outcomes can impose costs on signatory auditors through regulatory scrutiny, sanctions, litigation, reputational harm, reduced compensation, loss of clients, and impaired career advancement. 2 Consistent with tax aggressiveness imposing costs on auditors, prior studies find that tax aggressiveness is associated with a higher incidence of auditor resignations ( Goh et al., 2013 ) and higher audit fees ( Donohoe and Knechel, 2014 ).

While signatory auditors have incentives to curb tax aggressiveness, their ability to detect and prevent client tax aggressiveness is likely to vary. Auditors with tax expertise should have a greater ability to identify aggressive tax strategies that are likely to result in adverse outcomes, and thus are likely to be more effective at curbing aggressive tax planning than auditors without tax expertise. Therefore, we hypothesize that clients of signatory auditors with tax expertise are less tax-aggressive than clients of auditors who lack tax expertise.

Conclusions

We find that clients audited by tax-expert signatory auditors who only provide audit services are less tax aggressive than clients audited by non-tax experts. Consistent with a causal relation, we find that tax aggressiveness declines when mandatory auditor rotation results in switching to a tax-expert auditor. We also find that after an exogenous decrease in tax rates, which reduces clients’ incentives to engage in aggressive tax avoidance, the effect of tax expertise on tax aggressiveness weakens. In addition, while tax aggressiveness increases the incidence of tax-related restatements, tax-expert auditors attenuate this effect, consistent with tax-expert auditors mitigating the type of tax aggressiveness that increases misstatement risk. We also find that higher taxable income and a higher likelihood of tax-related audit adjustments are the channels through which tax-expert auditors constrain clients’ tax aggressiveness. Taken together, our findings fill a void in the literature and suggest that when signatory auditors only provide attestation services, their tax expertise reduces clients’ tax aggressiveness.

We note that our findings may not be directly generalizable to other settings. However, Lennox and Wu (2022) argue that “whether a study is likely to produce generalizable inferences hinges upon the nature of the theory being tested.” Because our theoretical prediction, which is that the engagement auditor’s tax expertise curbs tax aggressiveness, is not contingent upon the availability of the CTA-designation to capture auditors’ tax expertise, the generalizability concern is likely mitigated to some extent.