How Do You Determine Which Health Insurance Is Primary? 
In the increasingly rare situations where people have double health insurance coverage these days then the birthdate rule comes into play . For example , ahusband and wife are both employed at different companies and both are covering each other as spousal dependents on their respective employer 's group health plans . The health insurance plan of the spouse whose date of birth comes first in the year is designated as the `` primary '' plan that pays first and then the other spouse 's plan pays in a secondary capacity . 