客戶重要性與非審計服務是否影響審計品質？Enron後的觀察

Abstract

本研究旨在探討客戶重要性與非審計服務是否影響審計品質，並且為Enron後的觀察。過去文獻指出，客戶重要性或非審計服務與高估盈餘呈正相關，顯示審計品質受到危害；然而，Enron審計失敗導致簽證功能受到質疑，會計師在維持聲譽與限制法律責任的誘因下，審計決策可能有所不同。本研究以2002年與2003年由五大事務所查核之上市、上櫃公司共計1605筆觀察值為樣本，實證結果發現，客戶重要性與異常應計數的幅度呈顯著負相關，而這種關係主要是由於會計師越會限制重要客戶向上操縱盈餘所導致。若比較Enron前後期間，可發現Enron後會計師對於重要客戶更重視聲譽維護效果而傾向於採取保守的審計決策。至於非審計服務與異常應計數並不存在顯著關係，但「重大」非審計服務則可能因為較強烈的經濟依賴或藉由其他影響會計師獨立性之因素，使得會計師對於重要客戶傾向維護聲譽的誘因被弱化。

This study aims to examine whether the client importance and nonaudit services affect audit quality after the Enron fraud. Prior literature shows that client importance or nonaudit services are positively associated with earnings overstatements, which implies audit quality is impaired. However, due to audit failure in Enron, the attestation function has been challenged by the public. Under the incentives of reputation protection and legal liability restriction, the auditors’ decisions may change. With a sample of 1,605 observations audited by Big 5 in 2002 and 2003, we find that client importance has a significantly negative association with abnormal accruals, which is driven by auditors’ tendency to limit larger clients’ income increasing-accruals. Compare to pre-Enron period, auditors tend to adopt a more conservative strategy due to more focus on reputation protection in the post-Enron period. In addition, nonaudit services do not significantly associate with abnormal accruals. However, material nonaudit services may affect audit quality through stronger economic dependence or other threats to auditor independence, thus weaken auditors’ tendency to limit larger clients’ income-increasing accruals.