A meta-analysis of the factors influencing the impact of security breach announcements on stock returns of firms

Concurrent with the increase in organizations’ reliance on IT systems for conducting business with their consumers and partners, there have been increases in the risk and instances of security breaches of IT systems. As a result, a large body of research has been conducted to study the financial consequences of such security breaches in general and stock market reactions using the event study methodology in particular. Notwithstanding the significant contributions of the extant studies on the topic, inconsistencies could be observed about the existence and magnitude of shareholders’ reactions to announcements of security breaches by firms. As such, this paper addresses this gap through a meta-analysis of 63 studies (with a total of 20,936 instances of security breach announcements). The results suggest that a significant relationship exists between announcements of security breach and a drop in the experiencing firms’ stock returns. In addition, this relationship is impacted by the type of security breach, time of the security breach event, the country in which the experiencing firms operate, and the size of those firms.