In insurance, the insurance policy is a contract (generally a standard form contract) between the insurer and the insured, known as the policyholder, which determines the claims which the insurer is legally required to pay. In exchange for an initial payment, known as the premium, the insurer promises to pay for loss caused by perils covered under the policy language.
Insurance contracts are designed to meet specific needs and thus have many features not found in many other types of contracts. Since insurance policies are standard forms, they feature boilerplate language which is similar across a wide variety of different types of insurance policies.
The insurance policy is generally an integrated contract, meaning that it includes all forms associated with the agreement between the insured and insurer. In some cases, however, supplementary writings such as letters sent after the final agreement can make the insurance policy a non-integrated contract. One insurance textbook states that generally "courts consider all prior negotiations or agreements ... every contractual term in the policy at the time of delivery, as well as those written afterwards as policy riders and endorsements ... with both parties' consent, are part of written policy". The textbook also states that the policy must refer to all papers which are part of the policy. Oral agreements are subject to the parol evidence rule, and may not be considered part of the policy if the contract appears to be whole. Advertising materials and circulars are typically not part of a policy. Oral contracts pending the issuance of a written policy can occur.
The insurance contract or agreement is a contract whereby the insurer will pay the insured (the person whom benefits would be paid to, or on behalf of), if certain defined events occur. Subject to the "fortuity principle", the event must be uncertain. The uncertainty can be either as to when the event will happen (e.g. in a life insurance policy, the time of the insured's death is uncertain) or as to if it will happen at all (e.g. in a fire insurance policy, whether or not a fire will occur at all).
Insurance contracts were traditionally written on the basis of every single type of risk (where risks were defined extremely narrowly), and a separate premium was calculated and charged for each. Only those individual risks expressly described or "scheduled" in the policy were covered; hence, those policies are now described in retrospect as "individual" or "schedule" policies. This system of "specific risk" or "named perils" coverage proved to be unsustainable in the context of the Second Industrial Revolution, in that a typical large conglomerate might have dozens of types of risks to insure against. For example, in 1926, an insurance industry spokesman noted that a bakery would have to buy a separate policy for each of the following risks: manufacturing operations, elevators, teamsters, product liability, contractual liability (for a spur track connecting the bakery to a nearby railroad), premises liability (for a retail store), and owners' protective liability (for negligence of contractors hired to make any building modifications).