MMC Benefits Handbook
When to Make Changes
You may apply for domestic partner coverage within 30 calendar days of your first becoming eligible for plan coverage; within 30 calendar days of your first satisfying the domestic partner criteria; or during the Annual Enrollment period for coverage generally effective the next January 1.
Effective Date of Change
Your coverage will be effective on your first day of eligibility when you are Actively-At-Work if you are a Marsh & McLennan Companies or eligible MMA employee, as long as you apply for coverage within 30 calendar days of your first becoming eligible for plan coverage; on the date you first satisfy the domestic partner criteria if you apply within 30 calendar days of becoming eligible and your medical plan permits a mid-year enrollment; or on the next January 1 if you apply during the Annual Enrollment period.