Home/Glossary/Medicare Advantage Open Enrollment (MA-OEP)Glossary · EnrollmentMedicare Advantage Open Enrollment (MA-OEP)January 1 – March 31 each year. Allows one change from Advantage to Original Medicare or to a different Advantage plan.Related TermsInitial Enrollment Period (IEP)Annual Election Period (AEP)General Enrollment PeriodSpecial Enrollment Period (SEP)SHIPLate Enrollment PenaltyCOBRAEmployer Group Health Plan← Back to glossary index