本研究以台灣2020年8月所爆發之康友案來探討審計失敗是否在會計師事務所和會計師個人層面存在蔓延效果。本研究前半部分以事件研究法來檢測康友事件後，其簽證會計師事務所之客戶是否有較顯著之負累積異常報酬，並再進一步將康友簽證事務所之客戶區分為康友會計師簽證之客戶和其他會計師簽證之客戶；後半部分的研究則是以迴歸分析來檢測康友案後公司之債務資金成本變化，資訊風險會增加並影響債權人對公司之風險評估，進而要求更多補償，使得事件後康友簽證事務所其他客戶之債務資金成本增加，且康友簽證會計師之其他客戶會面臨更高的債務資金成本。
研究結果顯示康友案後僅在事件日二其簽證會計師事務所之客戶出現顯著之負累積異常報酬，且康友簽證會計師之客戶也在同日較同事務所其他會計師之客戶有明顯之負累積異常報酬趨勢，在事件日一與事件日三則未發現康友簽證事務所或會計師之其他客戶有顯著之負累積異常報酬，顯示康友案之蔓延效果主要集中於事件日二，代表審計失敗的確會影響投資人對事務所及會計師個人的看法，不過此蔓延效果的影響時間有限，部分符合預期。此外，實證結果發現康友案後其簽證事務所其他客戶之債務資金成本增加，不過並未觀察到康友簽證會計師之其他客戶有更高的債務資金成本，部分支持審計失敗會對債權人造成影響。

This study takes Pharmally as an example to explore whether contagion effect of audit failures exists at the audit firm and individual partner level. In the first half of this study uses the Event Study method to examine whether the clients of the Pharmally’s certified accounting firm had significant negative cumulative abnormal returns after the scandal, and further differentiated the clients of the Pharmally’s certified accounting firm into the clients of Pharmally’s audit partner and the clients of other audit partner. The second half of the study uses regression analysis to examine changes in the company's cost of debt after the scandal. The information risk will increase and affect the creditor's risk assessment of the company, and then they will ask more compensation, which will increase the cost of debt for other clients of Pharmally’s certified accounting firm, and other clients of Pharmally’s audit partner will have higher cost of debt.
The empirical result shows that only on the second event day, the clients of the Pharmally’s certified accounting firm had significant negative cumulative abnormal returns. In addition, the clients of Pharmally’s audit partner also had a significant negative cumulative abnormal returns trend compared with the clients of other audit partner in the same firm on the same day. On the first event day and third event day no significant negative cumulative abnormal returns were found for the clients of the Pharmally’s certified accounting firm or the clients of Pharmally’s audit partner. It shows that the contagion effect of the Pharmally Scandal is mainly focus on the second event day, which means that the audit failure will indeed affect investors' views on accounting firms and individual accountants. However, the impact time of this contagion effect is limited, and some of them are in line with expectations. The results of the regression analysis show that the cost of debt of other clients of Pharmally’s certified accounting firm increased after the Scandal, which proves that the audit failure will indeed have an impact on the creditors, but it is not observed that the other clients of the Pharmally’s audit partner have higher cost of debt.

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PressPlay 專欄作家 船長 (2020年8月12日)，康友董事長黃文烈二年前賣股、今年8月失聯，公司到底藏有什麼不可告人的祕密？。經濟日報。檢自：https://money.udn.com/money/story/5607/4777045。
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陳蕙綾 (2020年9月29日)，康友-KY涉掏空財報不實 勤業兩會計師遭停業二年 13年來最重懲處。鉅亨網。檢自：https://news.cnyes.com/news/id/4528739。
謝幸恩 (2020年8月10日)，〈獨家〉董座黃文烈債留康友 搬走7億文件曝光【股后窒息1】。毅傳媒。檢自：https://yimedia.com.tw/judicial/46350/?_trms=5e7979f7d5354c7a.1640678317979。
謝幸恩 (2020年8月10日)，老董神隱總座閃辭 康友慘入全額交割【股后窒息2】。毅傳媒。檢自：https://yimedia.com.tw/breaking-news-2/46353/

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