投資人決定是否依賴財務報表來判斷公司經濟實質的重要關鍵在於審計品質。當財務報表經由具備高審計品質之會計師事務所查核簽證時,則投資人預期會計資訊能真實反應經濟實質,對會計盈餘較具信心,盈餘與股價報酬間之相關性越高,進而增加盈餘資訊性。故本研究以盈餘與報酬間之關聯性,探討審計品質對盈餘資訊性之影響,以及受到博達事件之衝擊後,不同審計品質對盈餘資訊性之影響是否產生變化。實證結果顯示審計品質對盈餘資訊性有正面影響,即經由四大會計師事務所查核簽證之公司,其盈餘資訊性越高。而博達事件後(2004年後),會計師面對與日俱增之訴訟風險,聘請四大會計師事務所查核簽證之公司,相對於博達事件爆發前,其盈餘資訊性較高。
Audit quality is on of the key consideration factors whether investors would rely on financial statements to understand the economic reality of the firms. Higher quality auditors are more likely to deter and detect questionable accounting practices and also report those material errors and irregularities. Financial statements audited by higher quality auditors are more credible by investors. The purpose of this study is to examine the impact of audit quality on informativeness of earnings by way of testing the relationship between earning and stock price. We use audit firms’ size as a surrogate for audit quality. The results indicate that informativeness of earnings of Big 4 clients are much higher than those of non-Big 4 clients. These findings implied that audit quality has positive effect on informativeness of earnings. We also find that the impact of audit quality on earnings informativness is different before and after Promp Scandal (year 2004). That is, the impacts of audit quality are stronger after 2004.