Coordination of benefits, or COB, establishes the order in which multiple health plans pay when an insured is covered by more than one plan. For a dependent child covered by both married parents’ group health plans, the common “birthday rule” generally makes primary the plan of the parent whose birthday occurs earlier in the calendar year. The rule compares the month and day of birth, not the year. If both birthdays are the same, the plan that has covered the parent longer is generally primary.
The primary plan pays first according to its own policy terms. The secondary plan then considers the remaining eligible expense and may pay an additional amount, subject to its coordination-of-benefits provision. COB is intended to prevent duplicate recovery exceeding the actual covered expense while still allowing the insured to receive the benefit of multiple coverages.
Special rules can apply in divorce, custody, court-order, active-versus-retired employee, Medicare, and other situations. The producer should never assume that one generic rule governs every family arrangement. Plan documents and applicable law control. For examination purposes, the birthday rule is the standard answer when the parents are married and no special circumstance is stated.
References/topics from the Study Guide: Coordination of Benefits; Primary and Secondary Coverage; Birthday Rule; Group Health Insurance; Dependent Coverage.
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