Lesson 2.5 — Special Enrollment Period (SEP)

A Special Enrollment Period applies when Medicare enrollment is delayed because of coverage under a large employer group plan based on active employment.

For Part B, and Part A if you also delayed this benefit, your enrollment period starts the day you turn 65 and ends eight months after losing employer coverage. While you are provided with more time to enroll in Part B, it may not be wise and could lead to coverage gaps. Note that if the large employer offers COBRA, Medicare becomes the primary payor.

For Part D, the window is much shorter — only 63 days after losing “credible” drug coverage.

Because these timelines differ, many people unintentionally miss one while meeting the other. Understanding both deadlines is critical to avoiding penalties and gaps in coverage.

Three Key Points

1. SEP applies to people covered by large employer plans.
2. Part B and Part D deadlines are different.
3. Enroll before your plan ends to prevent coverage gaps.