A majority of courts consider the contra proferentem doctrine to be a pillar of insurance law. The doctrine requires ambiguous terms in an insurance policy to be construed against the insurer and in favor of coverage for the insured. A prominent rationale behind the doctrine is that insurance policies are usually standard-form contracts drafted entirely by insurers.
In certain cases, insurers have asserted two reasons for setting aside the contra proferentem doctrine: 1) the insured is a large, 'sophisticated' corporate entity which should not benefit from ambiguity in the policy when it had the bargaining power and/or expertise to modify the language; and 2) the insured actually participated in negotiating or drafting the policy and, therefore, should not benefit from ambiguity, when it is just as responsible as the insurer for any ambiguity that exists.