Insurance, in law and economics, is a form of risk management primarily used to hedge against the risk of a contingent, uncertain loss. Insurance is defined as the equitable transfer of the risk of a loss, from one entity to another, in exchange for payment. An insurer is a company selling the insurance; an insured or policyholder is the person or entity buying the insurance policy. The insurance rate is a factor used to determine the amount to be charged for a certain amount of insurance coverage, called the premium. Risk management, the practice of appraising and controlling risk, has evolved as a discrete field of study and practice.

The transaction involves the insured assuming a guaranteed and known relatively small loss in the form of payment to the insurer in exchange for the insurer's promise to compensate (indemnify) the insured in the case of a large, possibly devastating loss. The insured receives a contract called the insurance policy which details the conditions and circumstances under which the insured will be compensated.

Insurance involves pooling funds from many insured entities (known as exposures) in order to pay for relatively uncommon but severely devastating losses which can occur to these entities. The insured entities are therefore protected from risk for a fee, with the fee being dependent upon the frequency and severity of the event occurring. In order to be insurable, the risk insured against must meet certain characteristics in order to be an insurable risk. Insurance is a commercial enterprise and a major part of the financial services industry, but individual entities can also self-insure through saving money for possible future losses.

Global insurance premiums grew by 3.4% in 2008 to reach $4.3 trillion. For the first time in the past three decades, premium income declined in inflation-adjusted terms, with non-life premiums falling by 0.8% and life premiums falling by 3.5%. The insurance industry is exposed to the global economic downturn on the assets side by the decline in returns on investments and on the liabilities side by a rise in claims. So far the extent of losses on both sides has been limited although investment returns fell sharply following the bankruptcy of Lehman Brothers and bailout of AIG in September 2008. The financial crisis has shown that the insurance sector is sufficiently capitalised. The vast majority of insurance companies had enough capital to absorb losses and only a small number turned to government for support.

Advanced economies account for the bulk of global insurance. With premium income of $1,753bn, Europe was the most important region in 2008, followed by North America $1,346bn and Asia $933bn. The top four countries generated more than a half of premiums. The US and Japan alone accounted for 40% of world insurance, much higher than their 7% share of the global population. Emerging markets accounted for over 85% of the world’s population but generated only around 10% of premiums. Their markets are however growing at a quicker pace.