What is the Medicare Advantage OEP?

The Medicare Advantage open enrollment period, or MA OEP, is a Medicare enrollment period that runs from January 1 through March 31 each year. The MA OEP gives beneficiaries who are enrolled in a Medicare Advantage plan a chance to change their coverage. Changes are effective the first of the following month. Unlike the annual enrollment period, or AEP, the MA OEP is only available to some Medicare beneficiaries.