過去有關會計師產業專家的研究多聚焦於會計師若為產業專家是否能提升會計品質，少有研究探討會計師產業專家的訊息效果。本研究以關係人銷貨來探討此一議題。由於關係人交易的特殊性，當公司擁有大量的關係人交易時，外部投資人對於管理階層是否藉由關係人交易侵害股東權益之疑慮提高，此時公司管理階層為減輕外界疑慮，聘請聲譽良好的會計師(產業專家)來查核其財務報表成為管理者可選擇的方式之一。本研究的實證結果顯示，當公司關係人銷貨比例越高時，公司愈傾向借由聘請會計師產業專家來向外部投資人傳遞其財務報表可靠的訊息，且此一狀況在會計資訊品質較高的公司更為明顯。

Auditor industry expertise has become a popular issue in recent years. Many studies focus on the relationship between auditor industry expertise and audit quality. However, few researchers discuss the signaling function of auditor industry professionals. That is, companies hire auditor industry specialists to validate their financial reports and mitigate the investors’ concern. This study therefore tries to fill this gap. We choose related-party sales as our main test variable. First, we examine whether management prefers to hire an industry specialist when a company has a higher level of related-party sales, in order to audit its financial reports and thereby mitigate outside investors’ concern. The empirical results support this explanation and our findings are the same in both the firm and partner level. In addition, we find when a company has higher accounting information quality, its management is more likely to hire an auditor industry specialist. However, this hypothesis may be weakened if a company has independent director(s) on its board since both the roles of an independent director and a specialist are quite similar. Second, we test market reaction for hiring an auditor industry specialist. The results show when a company has higher accounting information quality and the amount of related-party sales increases, in some situations, hiring an auditor industry specialist can mitigate the negative concern from outside investors.