理論上，會計盈餘與課稅所得應為正相關。但是公司是否會在會計盈餘與課稅所得之間加以取捨，以從事盈餘管理，是一個尚待驗證的問題。當公司向上(向下)管理盈餘時，若課稅所得亦隨之增加(減少)，則表示其無法兼顧會計盈餘與課稅所得。即公司必須在盈餘與租稅之間「權衡取捨」。當公司向上(向下)管理盈餘時，課稅所得卻減少(增加)，則表示其可以兼顧會計盈餘與課稅所得，本文稱為「雙重盈餘管理」。本文以台灣的上市公司為研究對象，驗證台灣是權衡取捨或雙重盈餘管理。本文發現台灣的公司存在雙重盈餘管理之現象。本文進一步測試台灣的資本市場是否能夠「看穿」企業雙重盈餘管理之行為，及台灣的會計師面對企業進行雙重盈餘管理的方法。本文發現台灣的資本市場不是完全效率市場，而且台灣會計師對課稅所得的重視程度高於會計盈餘。 The relationship between accounting earning and taxable income should be positive in theoretical perspective. It is an interesting question to test corporations conduct dual earnings management or trade off between accounting earning and taxable income. When corporations raise (decrease) accounting earning by earnings management, and their taxable income decrease (raise). It means that corporations are able to manipulate both accounting earning and taxable income in the same time. We define it “dual earnings management.” Otherwise, we name it “trade-off strategy.” In this study, we use the TEJ data to test dual earnings management or trade-off relationship between accounting earning and taxable income in Taiwanese corporations. We also tested whether Taiwanese capital market can see through the phenomenon of dual earnings management. Moreover, we study Taiwanese CPAs’ audit quality if they face earnings management of corporations. We find that there are dual earning management from companies and the capital market is not efficient in Taiwan. Moreover, CPAs take care more for taxable income than accounting earning.
