SOX後會計師變更對審計品質的影響

Abstract

沙賓法案本身立法的目的是為了提高公司財務報表的品質，並且提振投資人對於公司財務報表資訊的信心。然而，在後沙賓時期卻有眾多的公司更換會計師，尤其大多從四大會計師事務所換成非四大會計師事務所，似乎與沙賓法案立法目的背道而馳。本文試圖釐清沙賓法案實施後會計師更換與審計品質間之關連性。本文以二個研究議題探討會計師變更對於審計品質的影響。第一、眾多從四大會計師事務所更換非四大會計師事務所的公司是否試圖進行盈餘管理？第二、分析師對於企業盈餘預測的準確度與離散程度，是否會因為企業更換會計師而有所不同。研究結果顯示，若以裁決性應計數作為審計品質的代理變數，在沙賓法案通過後，審計品質確實有所提升，但會計師變更與否則對審計品質無顯著影響，表示無足夠的證據說明後沙賓時期不同型態之會計師變更與盈餘管理有關。若以分析師盈餘預測品質作為審計品質的代理變數進行分析，也並無發現足夠的證據說明沙賓法案通過後之會計師變更對審計品質有所影響。

The Sarbanes-Oxley Act (hereafter referred as SOX) was enacted with the legislative intent to improve the quality of listed company’s financial statements so as to build up the investors’ confidence in the information obtained from such financial statements. The switching/changing of their audit firms by a number of listed companies after the passing of the SOX, however, seems to go against its legislative intent, resulting in the weakening of the company’s reporting quality. This study investigates whether the switch has caused adverse effects on audit quality. Specifically, I test the following two questions. First, does the quality of financial statements suffer as firms change their auditors from a Big 4 firm to a non-Big 4 firm? Second, what are the impacts of the auditor change on analysts’ forecast quality? Does the auditor change cause differences in analyst earnings forecast accuracy and/or forecast dispersion? This study uses two proxy variables for audit quality, i.e., degree of earnings management and analyst’ forecast quality, to investigate the influence of auditor change on audit quality in the post-SOX period. The result shows that discretionary accruals have significantly decreased after SOX, that is, the audit quality has indeed improved after the passing of SOX. However, no sufficient evidence is found to support that there is an adverse impact on the audit quality when companies change their auditor after the passing of SOX.