自民國77年起考選部大幅提高會計師錄取率後，審計市場中執業會計師人數與事務所開業家數均大增，導致整個產業之利潤率逐年下降。同時，財政部證券暨期貨管理委員會積極鼓勵事務所合併，希望能藉以提升審計品質，復見美國跨國性之八大會計師事務所逐漸合併成為五大，遂引發本文擬以財政部統計處78年至87年的「會計師事務所服務業調查報告」普查資料，採超越對數 (Translog) 成本函數，探討會計師錄取政策開放前後之會計師事務所成本函數之規模經濟課題。實證結果顯示，Translog 成本函數模型配通情形頗佳， 期間效果顯著為正，亦即後期全體會計師事務所總成本明顯較高，足見前、後二段期間會計師事務所成本結構確實有別。復作逐年迴歸分析，並據以計算各年度之平均規模經濟值，發現自民國81年度之規模經濟值1.175逐年下降至87年的1.098，顯見大量的新科會計師驟然湧入審計市場，造成中、小型會計師事務所林立，確實為競爭環境帶來衝擊。

In the late 1980s, the Ministry of Examination, responsible for conducting CPA exam affairs, determined to loosen the passing threshold of CPA examination in response to the increasing demand for accounting services. That led to a large amount of qualified CPAs flooding into the audit market and promoted competition in the profession. However, the regulation authority managed to improve audit quality and thus encouraged local accounting firms expanding their operating scale by merger. Meanwhile, the Big 8 accounting firms in the US merged into the Big 6 after the audit market restructured. Observing these contradicting phenomena, the authors of this study intend to estimate the cost functions for the accounting firms during the period of 1989 to 1998 by applying the Translog cost function model, proposed by Christensen, Jorgensen, and Lau (1973), on Taiwan's official survey data. Specifically, this paper estimates the range of the economies of scale for accounting firms in order to examine the effect that the government lifted the entry barrier on the firms' cost structure. The empirical results show the cost structure changes significantly and its mean value of economies of scale decreases after CPA passing threshold loosened, especially from 1.175 for 1992 to 1.098 for 1998. Consequently, CPA firms revise their respective competition strategies in response to such drastic changes of the whole industry.