Expanding the Gordon-Loeb Model to Cyber-Insurance

We present an economic model for decisions on competing cyber-security and cyber-insurance investment based on the Gordon-Loeb model for investment in information security. We consider a one-period scenario in which a firm may invest in information security measures to reduce the probability of a breach, in cyber-insurance or in a combination of both. The optimal combination of investment and insurance under the assumptions of the Gordon-Loeb model is investigated via consideration of the costs and benefits of investment in security alongside purchasing insurance at an independent premium rate. Under both exponential (constant absolute risk aversion) and logarithmic (constant relative risk aversion) utility functions it is found that when the insurance premium is below a certain value, utility is maximised with insurance and security investment. These results suggest that cyber-insurance is a worthwhile undertaking provided it is not overly costly. We believe this model to be the first attempt to integrate the Gordon-Loeb model into a classical microeconomic analysis of insurance, particularly using the Gordon-Loeb security breach functions to determine the probability of an insurance claim. The model follows the tradition of the Gordon-Loeb model in being accessible to practitioners and decision makers in information security