This paper looks at the dynamic properties of insurance contracts when insurers have better technology at preventing catastrophic losses than the insured. The prevention technology is owned by the insurers and is permanent. If long-term contracts are not possible, the insured is faced with a commitment problem since he may want to renegotiate the contract or change insurer after his initial insurer has invested in prevention. Because of this hold-up problem, we find that the investment in prevention is delayed.