Annuities provide a stream of payments and are generally classified as insurance because they are issued by insurance companies, are regulated as insurance, and require the same kinds of actuarial and investment management expertise that life insurance requires. Annuities and pensions that pay a benefit for life are sometimes regarded as insurance against the possibility that a retiree will outlive his or her financial resources. In that sense, they are the complement of life insurance and, from an underwriting perspective, are the mirror image of life insurance.
In the United States, economists and consumer advocates generally consider insurance to be worthwhile for low-probability, catastrophic losses, but not for high-probability, small losses. Because of this, consumers are advised to select high deductibles and to not insure losses which would not cause a disruption in their life. However, consumers have shown a tendency to prefer low deductibles and to prefer to insure relatively high-probability, small losses over low-probability, perhaps due to not understanding or ignoring the low-probability risk. This is associated with reduced purchasing of insurance against low-probability losses, and may result in increased inefficiencies from moral hazard.
When insured parties experience a loss for a specified peril, the coverage entitles the policyholder to make a claim against the insurer for the covered amount of loss as specified by the policy. The fee paid by the insured to the insurer for assuming the risk is called the premium. Insurance premiums from many insureds are used to fund accounts reserved for later payment of claims – in theory for a relatively few claimants – and for overhead costs. So long as an insurer maintains adequate funds set aside for anticipated losses (called reserves), the remaining margin is an insurer's profit.