题  目：Does Delayed Disclosure of Cybersecurity Breaches Influence Short Selling and

Insider Trading?

报告人：袁歆，纽约城市大学巴鲁克分校，博士研究生

时  间：2019年9月25日（星期三），15：00-16：30

地  点：嘉庚一404室

主持人：杜兴强  教授

参 加 者：对会计、财务研究有兴趣的师生

论文摘要：We examine the impact of delayed disclosure of cybersecurity breaches on short selling and insider trading. Our study shows, first, that when US public companies become aware of a cybersecurity breach, they delay its disclosure for an average 21 trading days. Second, delayed breach disclosures are followed by a two-day stock market reaction averaging 138 negative basis points. Therefore, such delay can provide a profitable opportunity for short sellers and company insiders. We further find significant shifts before breach disclosures in two types of stock trading, i.e. a 15% average increase in short interest ratios and an 89% average decrease in insider stock purchases. However, we do not find that company insiders take advantage of their foreknowledge by selling stocks during the same period. Overall, our study shows that US public companies are inclined to delay disclosure of cybersecurity breaches, thus benefiting investors with advance knowledge of breaches.