關係人交易是集團企業經常採用之方式，正常之關係人交易可以提升經營績效。然而，不當之關係人交易，卻是集團企業管理者操弄財務報表的工具。集團企業之會計師若能瞭解關係人交易的內容與特性，將有助於其判斷關係人交易的合理性，進而能抑制不當之關係人交易。本文發現整體而言，國內大部分集團企業仍然委託不同事務所查核，會計師因無法完整瞭解關係人交易，故集團企業會利用營業外活動，進行不當之關係人交易，導致財務報表的盈餘持續性較低。然而，相較於委託不同事務所查核，當集團企業委託同一事務所查核，其營業活動外關係人交易較不會降低盈餘持續性。而此結果僅限於集團企業委託同一大型事務所查核，或是集團企業屬於大型者。

Related party transactions are conducted between components within an affiliated business group and these transactions in the normal course of operations are beneficial for the improvement of the operating performance of the group. However, abnormal related party transactions can be used by managers of the group to manipulate financial statements. If auditors of the group can better understand the content and characteristics of related party transactions, then they can determine the rationality of the transactions and further inhibit improper transactions more accurately. The findings of this study indicate that most components of an affiliated business group are audited by auditors from different CPA firms that do not fully understand the nature of related party transactions. As such, affiliated business groups may conduct related party transactions by means of nonoperating activities, which could decrease earnings persistence. Yet, when components of the affiliated business group are audited by the same firm, as opposed to being audited by different firms, earnings persistence would not be decreased. It is noteworthy that the results have to do with the significance of the companies under discussion for the following: either the CPA firm conducting the audits is big or the affiliated business group itself is big.