On average, which of the following types of investors has the shortest investment horizon?

Property and casualty insurers may need to distribute funds at any time if a disaster occurs. Endowment funds have a very long horizon, as they are often expected to operate in perpetuity with only annual distributions representing a relatively small percentage of the fund value. Defined benefit plans have an investment horizon based on the years to retirement of currently covered workers and the years they (and their beneficiaries) are expected to live after retirement.