供應鏈聘任相同會計師對公司租稅規避程度之影響

The Effects of Sharing the Same Supply Chain Auditor on Corporate Tax Avoidance

本文係探討供應鏈聘任相同會計師事務所對我國上市櫃公司租稅規避之影響。結果顯示當公司與供應鏈之主要公司聘任相同會計師事務所時，永久性財稅差異較高。且該影響會因客戶重要性的增加而減弱，即客戶重要性愈高時，會計師將採取更保守的租稅規劃策略，避免公司採行激進之租稅規劃。此外，本文進一步探討供應鏈聘任相同會計師事務所對公司租稅規避程度之影響是否因供應鏈所屬階段而不同。結果發現，當公司與主要上游供應商或下游客戶聘任相同會計師事務所時，皆有較大之永久性財稅差異，惟公司同時僅與其上游及下游皆聘任同一會計師事務所時，未發現有較激進之租稅規劃。本文提供會計師事務所影響供應鏈相關公司之租稅規劃的實證證據，除延伸供應鏈相關之研究之外，亦可作為管制機關未來抽查公司稅負之參考。

With a sample drawn from listed companies in Taiwan, this study examines the effect of appointing the same supply chain auditor on tax avoidance. Our results indicate that companies exhibit greater permanent book-tax differences when they engage the same audit firm within their supply chain. Besides, we find that the effect of engaging the same audit firm on tax avoidance diminishes with an increase in client importance. It suggests that higher client importance prompts supply chain auditors to adopt aggressive tax planning strategies for their clients. Furthermore, we investigate whether the effect varies across channel partners with which a company shares the same audit firm. We find that no matter when companies engage the same audit firm as their major suppliers or customers, they all have greater permanent book-tax differences. However, such an effect diminishes when companies simultaneously engage the same audit firm as both their major suppliers and customers. In addition to extending prior research on supply chain auditors, our study also could provide insights to the tax authorities in conducting tax inspections and tax audits.