本文以合夥型會計師事務所為對象，並將其按有／無承辦公開發行公司財務簽證業務而區分為大／小型會計師事務所，以探討其「市場佔有率—利潤」間是否存在正相關，及取消審計公費下限是否會影響會計師事務所之利潤與「市場佔有率－利潤」之關係。使用我國財政部1992-2003 年「會計師事務所服務業調查報告」之普查資料進行實證，結果顯示，合夥型會計師事務所之市場佔有率愈高，經營利潤愈高，且審計公費下限取消後，大型會計師事務所之市場佔有率與利潤間的正相關更為顯著。取消審計公費下限之事件中，當媒體傳播「會計師公會訂定酬金標準違法」，對合夥型會計師事務所之利潤造成顯著下降的影響，但後續之事件，即「會計師公會修正酬金標準規定，以取消會計師對其嚴格的遵守」，則未對事務所之經營利潤造成顯著影響。

This paper examines the relationship between market share and profitability of
partnership public accounting firms. Furthermore, the effects of the cancellation of audit
fee floor on profit and on the relationship between market share and profitability are
investigated. For those accounting firms offering services to the public companies, we
define them as large firms. Public accounting firms offering services to private companies
are then defined as small firms. Data are obtained from the 1992~2003 Census Report of
Public Accounting Firms in Taiwan. Empirical results reveal positive relationship between
market share and profitability. After the cancellation of audit fee floor, the above
relationship is much significant for the large public accounting firms. After the media
reporting that the audit fee floor established by the Taiwan Institute of Certified Public
Accountant was illegal, the operating profit of public accounting firms declined. However,
the cancellation of audit fee floor by the Taiwan Institute of Certified Public Accountant
had no effect on the operating profit of public accounting firms.