감사시간, 감사보수 및 시간당보수의 증가가 조세회피에 미치는 영향

In this paper, we examine whether the increase in audit effort are associated with lesser tax avoidance. The audit hours, audit fees, and audit fees per hours have increased since the implementation of the Standard Audit Hours System (hereafter ‘SAHS’) in 2019 compared to the previous years (e.g., Lee et al. 2021 ；Jung et al. 2022；Park and Jeon 2022 etc.). Moreover, prior studies also show that the increase in audit hours, audit fees, and audit fees per hours could lead to greater audit quality (Kim and Jung 2020；Jung et al. 2022；Sim et al. 2022 ；Park and Jeon 2022；Kim and Park 2023 etc.). Therefore, we test that the increase in audit hours, the increase in audit fees, and the increase in audit fees per hours as a proxy for audit effort are significantly and negatively associated with tax avoidance. For our empirical tests, we use a sample of firms with positive pretax income and data from 2018 through 2022 to construct four tax avoidance measures：the book-tax income differences (BTD), the discretionary BTD (hereafter DDBTD) based on Desai and Dharmapala (2006), the current cash effective tax rate (hereafter CETR), and the GAAP ETR (hereafter GETR). To study the effect of auditor’s audit effort on tax avoidance, we use three audit effort proxies：the increase in audit hours (hereafter ΔAH), the increase in audit fees (ΔAF), and the increase in audit fees per hours (ΔAFH). The final sample in our study is 4,713 firm-year observations in the KOSPI and KOSDAQ listed firms from 2018 to 2022. Our empirical results are as follow. First, we find that ΔAH is negatively and significantly associated with these one alternate proxies of tax avoidance (i.e., CETR) as the dependent variable. In additional tests, we partition the sample into pre- and post-SAHS adoption period, we find that ΔAH is negatively and significantly associated with these three alternate proxies of tax avoidance (i.e., BTD, DDBTD, CETR) is stronger during post-SAHS period. Additionally, we also divided the sample into KOSPI and KOSDAQ, our result is driven by the KOSPI sample. Second, we find that ΔAF is negatively and significantly associated with these three alternate proxies of tax avoidance (i.e., BTD, DDBTD, CETR). Additionally, we partition the sample into pre- and post-SAHS period, we find that ΔAF is negatively and significantly associated with these four alternate proxies of tax avoidance (i.e., BTD, DDBTD, CETR, GETR) is more pronounced in the post-SAHS period. We also divided the sample into KOSPI and KOSDAQ, our results are driven by the KOSPI sample. Lastly, we do not find that ΔAFH is significantly negatively associated with tax avoidance. However, we divided the sample into KOSPI and KOSDAQ, we find that ΔAFH is negatively and significantly associated with these two alternate proxies of tax avoidance (i.e., BTD, DDBTD) has a more pronounced relation with firms listed on the KOSPI. Overall, our results show that the increase in audit hours, the increase in audit fees, and the increase in audit fees per hours as a proxy for audit effort are negatively associated with tax avoidance differs between the pre- and post-SAHS periods, and between KOSPI and KOSDAQ sample and that these association has a more pronounced in the post-SAHS period and the KOSPI sample. Hence, we contribute to this research by documenting that the negative association between audit effort and tax avoidance. Moreover, we are the first to study the role of financial statement audits in constraining corporate tax avoidance through audit effort. As well as we find a negative association between audit effort and tax avoidance, supporting the argument that financial statement audits constrain corporate tax avoidance through greater audit effort, and we also find that the negative association between audit effort and tax avoidance is more pronounced in the post-SAHS period is to empirically present that the implementation of SAHS was effective in improving audit quality as well as lead to reduce tax avoidance. Therefore, it is expected that our findings could provide policy implications for supervisory authorities and policymakers. Furthermore, we contribute to the growing but limited research examining the link between audit effort and tax avoidance.