3.4 Special Enrollment Periods (SEPs) & Qualifying Life Events

Why SEPs Matter on the Exam

Special Enrollment Periods are where AHIP scenario questions get the most specific, because SEPs are not a single rule — they are a whole family of event-triggered windows, each with its own trigger, length, and set of permitted changes. A typical exam question describes a life event ("Mrs. Kim moved to a different county in June" or "Mr. Diaz lost his employer coverage when he retired") and asks you to identify which SEP applies and what it allows. Getting the category of trigger right is the whole skill being tested.

The Core SEP Categories

Dual Eligibility and LIS: The 2025 Change Agents Must Know

For years, full-benefit dually eligible beneficiaries (those with both Medicare and full Medicaid) and beneficiaries receiving the Low-Income Subsidy (LIS / Extra Help) used a quarterly SEP (one election per calendar quarter for the first nine months of the year), a rule that had been in place since 2019. Effective January 1, 2025, CMS replaced that with an integrated, once-per-calendar-month SEP for these populations — they can now enroll in, disenroll from, or switch MA/Part D coverage every single month, with changes effective the first of the following month. This is a current, testable change: older training materials that still describe a quarterly dual-eligible SEP are now out of date.

Worked example: Mr. Thompson is dually eligible for Medicare and full Medicaid. In March, he wants to switch from one D-SNP (Dual-Eligible Special Needs Plan) to another. Under the current rule, he can do this immediately — he does not have to wait for a specific quarter to open, and he can do it again in April if needed.

The Move SEP in Detail

A permanent move outside a plan's service area is one of the most commonly tested SEPs. Key details:

• If the beneficiary tells the plan before moving, the SEP begins the month before the move and runs for 2 months after the move.
• If the beneficiary reports the move after it already happened, the SEP begins the month the plan is notified and runs 2 months after that.
• A move to a new address that is still within the same plan's service area does not trigger this SEP — the plan hasn't actually changed availability.

The Employer Coverage Loss SEP

Losing group health coverage from an employer or union — most often at retirement — opens a 63-day SEP to enroll in Part D or Medicare Advantage. This SEP matters twice over: it lets the beneficiary enroll outside AEP, and if the lost employer coverage was "creditable" (as good as or better than standard Part D), enrolling within this window means the beneficiary avoids the Part D late-enrollment penalty entirely (Section 3.5).

The 5-Star SEP

CMS rates every MA and Part D plan on a 1-to-5 star quality scale annually (see Chapter 6 for Star Ratings). If a 5-star plan is available in a beneficiary's service area, that beneficiary gets a special one-time window — December 8 through November 30 of the following year — to switch into it, regardless of what other enrollment period is or isn't currently open. This SEP can only be used once per that window.

Common Exam Traps

• Treating every life change as an SEP trigger — moving to a new address within the same service area, for example, is not a qualifying event.
• Forgetting that the dual-eligible/LIS SEP is now monthly, not quarterly, as of 2025.
• Confusing the 63-day employer-coverage-loss SEP with the general "loss of any coverage" — the SEP specifically requires the lost coverage to have been employer/union group coverage (or another qualifying source CMS defines) to trigger the window.
• Assuming an SEP allows unlimited changes the way AEP does — most SEPs (aside from the monthly dual/LIS SEP) permit only the single change tied to the triggering event.