Abstract
In this paper, we estimate the cost of a data breach using the number of compromisedrecords. The number of such records is predicted by means of a machine learning model,particularly the Random Forest. We further analyse the fat tail phenomena which capturethe underlying dynamics in the number of affected records. The objective is to calculatethe maximum loss in order to answer the question of the insurability of cyber risk. Ourresults show that the total number of affected records follow a Frechet distribution, andwe then estimate the Generalized Extreme Value (GEV) parameters to calculate the valueat risk (VaR). This analysis is critical because it gives an idea of the maximum loss thatcan be generated by an enterprise data breach. These results are usable in anticipatingthe premiums for cyber risk coverage in the insurance markets.