The Theory of Optimal Investment in Information Security and Adjustment Costs: An Impulse Control Approach

This paper applies the theory of real options and impulse control to information security investment and derives properties of an optimal investment rule. It also incorporates adjustment costs incurred whenever the level of the investment changes. We observe among others that if firm has opportunity of multiple investments, it behaves so cautiously that the timing is earlier and to invest more. Both adjustment costs and volatility of threat make interval of the investment longer, while vulnerability leads to shorter interval and therefore frequent investment.