This article presents a System Dynamics model that determines the optimal level in which to invest in information security and wish to reflect delay which can happen between factors and analyze information security investment effect. We Look into how investment of information security can have an effect on information security while analyzing the causal factors in information secure industry. Finally, research feedback loop which decreases necessity of information secure when satisfaction is fully enough because of information security investment.

Keywords: information security (IS), investment of IS, side effect, optimum level of IS, System Dynamics.