Medicare is the federal health insurance program for individuals aged 65 and older and those with certain disabilities. Navigating this program requires beneficiaries to understand a specific calendar of enrollment periods. These defined windows ensure individuals have regular opportunities to match their health coverage to their medical and financial needs. The Annual Enrollment Period (AEP) is the most important yearly event for current Medicare beneficiaries to review and adjust their plans.
Defining the Annual Enrollment Period (AEP)
The Annual Enrollment Period (AEP) is a fixed, yearly window that runs from October 15th through December 7th. This timeframe is the primary annual opportunity for millions of current Medicare beneficiaries to make changes to their health and prescription drug coverage for the upcoming calendar year. The structure and rules governing this period are established by the Centers for Medicare & Medicaid Services (CMS).
The AEP allows beneficiaries to account for any changes in plan costs, coverage, and provider networks that private insurers implement each year. All Medicare Advantage and Part D plans must send an Annual Notice of Change (ANOC) by the end of September, which alerts enrollees to these modifications. Beneficiaries can use the AEP to shop for new plans if their current coverage will no longer meet their needs or if they find a more affordable option.
This period is specifically for individuals who are already enrolled in Medicare Part A and/or Part B to adjust their existing coverage choices. If a beneficiary is satisfied with their current plan and it is still available, they do not need to take any action, and their coverage will generally renew.
Permitted Actions During AEP
The AEP allows beneficiaries to make significant changes involving Medicare Advantage (Part C) and Medicare Prescription Drug (Part D) coverage options. This ensures coverage aligns with an individual’s changing health status, prescriptions, and financial situation.
One common action is switching from Original Medicare (Part A and Part B) to a Medicare Advantage Plan (Part C). Conversely, a person enrolled in a Medicare Advantage Plan may choose to disenroll and return to Original Medicare. This move often involves enrolling in a separate Medicare Prescription Drug Plan (Part D) to ensure continued drug coverage.
Beneficiaries can also switch from one Medicare Advantage Plan to a different Part C plan offered by the same or a different private insurer. Since private plans change their benefits, premiums, and networks annually, the AEP provides the opportunity to move. Furthermore, beneficiaries are able to join, switch between, or drop a stand-alone Medicare Prescription Drug Plan (Part D).
Distinguishing AEP from Other Enrollment Periods
The AEP is distinct because it is a fixed, annual event for existing beneficiaries to review their current coverage. Other enrollment periods are typically triggered by specific personal circumstances or are for first-time enrollment. Confusing these timeframes can lead to coverage gaps or late enrollment penalties.
Initial Enrollment Period (IEP)
The IEP is the seven-month window surrounding an individual’s 65th birthday or the 25th month of receiving disability benefits, used for enrolling in Medicare for the first time. Unlike the AEP, the IEP is unique to each person based on their eligibility date. Missing the IEP for Part B enrollment can result in a late enrollment penalty and may require waiting for the General Enrollment Period (GEP).
General Enrollment Period (GEP)
The GEP runs annually from January 1st through March 31st for individuals who missed their IEP and want to enroll in Original Medicare Part B. Changes made during the GEP do not take effect until July 1st of that same year, creating a delay in coverage. This differs from the AEP, which covers changes to Part C and Part D and has an earlier effective date.
Special Enrollment Periods (SEP) and Open Enrollment Period (OEP)
Special Enrollment Periods (SEP) are triggered by specific life events, such as moving out of a plan’s service area or losing employer-sponsored coverage. The duration and scope of an SEP depend entirely on the qualifying event. The Medicare Advantage Open Enrollment Period (OEP), which runs from January 1st to March 31st, only allows those already on a Medicare Advantage plan to switch to another Part C plan or switch back to Original Medicare.
When New Coverage Takes Effect
The effective date of any coverage changes made during the AEP is standardized. Regardless of when a beneficiary makes a selection between October 15th and December 7th, the new plan or change will not become active immediately. All enrollment changes processed during the AEP become effective on January 1st of the following calendar year.
A person’s current Medicare coverage remains in place throughout the remainder of the year. Individuals must continue using their existing insurance for healthcare services until the January 1st start date of their new plan. This standardized effective date ensures a seamless transition of coverage.