  DDoS attacks are increasingly used by `hackers' and `hacktivists' for various
purposes. A number of on-line tools are available to launch an attack of
significant intensity. These attacks lead to a variety of losses at the
victim's end. We analyse the impact of Distributed Denial-of-Service (DDoS)
attack announcements over a period of 5 years on the stock prices of the victim
firms. We propose a method for event studies that does not assume the
cumulative abnormal returns to be normally distributed, instead we use the
empirical distribution for testing purposes. In most cases we find no
significant impact on the stock returns but in cases where a DDoS attack
creates an interruption in the services provided to the customer, we find a
significant negative impact.
