OEP (Medicare Advantage Open Enrollment Period)
The January 1 – March 31 window during which MA enrollees can make a one-time switch to another MA plan or back to Original Medicare + PDP.
Full Definition
The Medicare Advantage Open Enrollment Period (MA OEP) runs January 1 through March 31 each year. MA OEP is not the same as AEP. During MA OEP, beneficiaries already enrolled in a Medicare Advantage plan can make ONE change: either switch to a different MA plan or disenroll from MA back to Original Medicare (and add a standalone PDP). MA OEP does NOT permit Original Medicare enrollees to move into MA for the first time. CMS strictly prohibits agents from marketing to beneficiaries for the purpose of prompting OEP changes — all OEP contact must be beneficiary-initiated. OEP is therefore a "service window" more than a prospecting window, though inbound leads remain valuable.
Example
A beneficiary enrolled an MA-PD during AEP, discovered in January that their cardiologist is out-of-network, and calls their agent in February to switch MA plans. The switch is an OEP-permitted change.
Related Terms
- AEP (Annual Enrollment Period) — The October 15 – December 7 annual window during which Medicare beneficiaries can enroll in, switch, or drop Medicare Advantage and Part D plans.
- Medicare Advantage (Part C) — Private insurance plans that deliver Medicare Part A and B benefits (and usually Part D) as an alternative to Original Medicare.
- IEP (Initial Enrollment Period) — The 7-month window around a consumer's 65th birthday during which they can first enroll in Medicare Parts A, B, C, and D.
- SEP (Special Enrollment Period) — A year-round enrollment window triggered by qualifying life events — loss of coverage, move, marriage, income change — that allows enrollment outside OEP.
- MCMG (Medicare Communications & Marketing Guidelines) — The CMS rulebook that governs how Medicare Advantage and Part D plans, FMOs, TPMOs, and agents may market and communicate with beneficiaries.