UK: As premiums are payable in advance it follows that at any one time, e.g. end of the financial year, most policies will have an unexpired term to complete. The premium earned is the pro rata share of the premium relating to the period that has expired.
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Portion of the premium for a single Policy or group of policies, that an Insurer is entitled to recognize as earned revenue because a similar portion of the coverage period has elapsed. For example, under an annual Policy, one-third of the total premium is earned after the first four months of coverage.
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That part of a premium that relates to so much of the period of insurance as has already run.