This paper analyses cyber risk in the financial sector. It identifies and assesses the impact of cyber-attacks on share prices, distinguishing between commercial banks and other financial entities. Event study methodology is used to show that announcements of cyber-attacks led to negative reactions in the global stock market from 1995 to 2015. The most dangerous attacks are those non-confidential, i.e. viruses and worms, Dos-attacks and system breakdowns, rather confidential breaches, i.e. unauthorized access to confidential information. Our results show the need to invest in cyber security measures.
