Medicare Glossary

Annual Enrollment Period (AEP)

The period each year from October 15 through December 7 when Medicare beneficiaries can change their Medicare Advantage or Part D drug plans. Changes take effect January 1 of the following year.

Also known as: Fall Open Enrollment

Annual Notice of Change (ANOC)

A document that Medicare Advantage and Part D plans must send to enrollees by September 30 each year. It outlines any changes to the plan's costs, coverage, or service area that will take effect January 1.

Also known as: ANOC

Disenrollment

The process of leaving a Medicare Advantage or Part D plan. You can only disenroll during specific enrollment periods, such as the Annual Enrollment Period or a Special Enrollment Period. When you disenroll from a Medicare Advantage plan, you return to Original Medicare.

Evidence of Coverage (EOC)

A detailed description of what your Medicare Advantage or Part D plan covers, how much it costs, and how the plan works. Plans must send you an EOC each year by October 15.

Also known as: EOC

Late Enrollment Penalty

A higher premium added permanently to your Part B or Part D premium if you don't sign up for coverage when you are first eligible and don't have other qualifying coverage. The Part B penalty is 10% for each full 12-month period you were eligible but didn't enroll. The Part D penalty is 1% of the national base premium per month.

Also known as: LEP

Open Enrollment Period (OEP)

For Medicare Advantage, the period from January 1–March 31 each year when enrolled MA beneficiaries can switch to a different MA plan or return to Original Medicare (with Part D if desired). Changes take effect the first of the following month.

Also known as: OEP, Medicare Advantage OEP

Summary of Benefits

A standardized document that Medicare Advantage and Part D plans must provide that summarizes the plan's costs, covered benefits, and important rules. It is a shorter, easier-to-read version of the Evidence of Coverage.

ZIP Code Enrollment

The process of using your ZIP code to find Medicare Advantage or Part D plans available in your area. Plan availability, provider networks, and premiums can vary significantly based on your geographic location.