The value of cybersecurity : Stock market reactions to security breach announcements

Sammanfattning: Companies around the world invest an increasing amount of money trying to protect themselves from cybercrime and unauthorized access of valuable data. The nature of these covert threats makes it seemingly impossible to quantify the risk of getting attacked. While it is possible to estimate the tangible costs of a security breach it is much harder to asses what a company stands to lose in terms of intangible costs. This thesis uses the Event Study methodology to determine the intangible losses of listed American companies who suffered data breaches. On average, the companies in the dataset loses 0.21% of their market cap after a security breach which, although not being statistically significant, translates to $267 million. Despite looking at several parameters to find significant predictors, only one turned out to be statistically significant, namely the number of records breached. These weak correlation is a result in itself; because of the low impact of a breach perhaps the companies lack proper incentives to protect their users' data.