Medigap Open Enrollment Period

The Medigap open enrollment period is the six-month window created by 42 U.S.C. 1395ss(s)(2)(A), during which an insurer "may not deny or condition the issuance or effectiveness of a medicare supplemental policy, or discriminate in the pricing of the policy, because of health status, claims experience, receipt of health care, or medical condition." It runs from the first month as of the first day on which the individual is both 65 years of age or older and enrolled for benefits under Part B.

The name is Medicare's rather than the statute's. Congress placed the window inside a subsection headed "Coverage for pre-existing conditions" and never called it an open enrollment period; CMS supplies that label, and states it as a proper term: "Your one-time Medigap Open Enrollment Period starts once you sign up for Part B and lasts for 6 months." It is worth separating from the other windows that share the phrase. Medicare's annual open enrollment in the autumn, the Medicare Advantage open enrollment period in the first quarter, and the Marketplace open enrollment are all different things with different rules, and none of them reopens this one.

Both conditions have to be satisfied at the same time, which is where the surprises come from. The statutory trigger is the first month in which the individual is 65 or older and enrolled in Part B. Someone who came onto Medicare before 65 through disability and has held Part B for years does not have a window running during those years; it opens the month they turn 65. Someone who delayed Part B while covered by an employer plan does not have a window at 65; it opens when Part B begins. Medicare states the second case explicitly, and adds a detail people miss: the period "starts once you sign up for Part B and lasts for 6 months, even if you sign up for Part B while you still have employer coverage." So signing up for Part B early, while intending to keep working, can start and finish the window while the person is not yet shopping for a supplement.

What the protection actually covers. Three separate things are barred, and the third is the one that matters most in practice. An insurer may not refuse to issue the policy. It may not condition the issuance or the effectiveness of the policy. And it may not discriminate in the pricing of the policy on grounds of health status, claims experience, receipt of health care or medical condition, which means the applicant is charged the same premium as any other applicant of their age and location. A guarantee of issuance without a guarantee of price would be worth very little, and the statute closes that door in the same sentence. Subparagraph (E) separately bars the use of genetic information in either the issuance or the pricing of a policy.

Guaranteed issue is not the same as no waiting period, and this is the distinction most consumer material collapses. Subparagraph (B) provides that subparagraph (A) "shall not be construed as preventing the exclusion of benefits under a policy, during its first 6 months, based on a pre-existing condition for which the policyholder received treatment or was otherwise diagnosed during the 6 months before the policy became effective." So an insurer that must sell the policy at the standard price may still decline to pay for a specific known condition for half a year. Two provisions cut that back. Subparagraph (D) credits prior continuous creditable coverage: six months or more of it and the policy "may not exclude benefits based on a pre-existing condition"; less than six months and the exclusion is reduced by the coverage the applicant has. And subparagraph (C) provides that a policy replacing another that has been in force for six months or longer may impose no new waiting period at all for similar benefits. Someone moving from an employer plan straight onto Medicare therefore usually carries enough creditable coverage to remove the exclusion outright.

Missing it is expensive in a way that has no annual fix. Outside this window and outside the specific guaranteed-issue situations the statute creates elsewhere, a Medigap insurer may use medical underwriting: it may ask health questions, charge more, or decline the application. There is no once-a-year opportunity that cures this, which is what makes the Medigap decision different in kind from the Medicare Advantage decision. Someone choosing Medicare Advantage at 65 and expecting to switch later should know that the route back is narrower, and generally runs through a trial right or another guaranteed-issue situation rather than through this window.

Two boundaries on how far the federal rule reaches. Medicare's own guide states that federal law "generally doesn't require insurance companies to sell Medigap policies to people who are under 65," while some states do require it and on their own terms. And several states add rights the federal statute does not contain, such as an annual or birthday period in which existing policyholders may switch without underwriting. Which states, and on what terms, is a question for a state insurance department, and a list assembled from secondary sources goes stale without warning.

1. Find the month both conditions are first true. You are 65 or older, and your Part B coverage is in force. The window begins with that month.

2. Count six months from it. A window beginning in September runs through the end of February. It does not extend, and it does not repeat.

3. Compare policies by letter, then by price. Benefits within a letter are standardized, so the guarantee of price is what makes the comparison genuinely a price comparison during this window.

4. Apply within the window, not merely decide within it. The protection attaches to an application submitted before or during the six months.

5. Establish your creditable coverage. If you are coming off an employer plan, keep the evidence. Six months or more of prior continuous creditable coverage removes the pre-existing-condition exclusion entirely.

6. Buy drug coverage separately. A Medigap policy covers no outpatient prescriptions, so Part D is a separate decision made on its own timetable.

A hypothetical, contrasting two people with the same birthday. Ruth and Wanda both turn 65 in June.

Wanda enrolls in Part B effective 1 June. Both conditions are true that month, so her window runs June through the end of November. She decides she does not need a supplement and does nothing. At 68 she changes her mind; her window closed nearly three years earlier, and unless a guaranteed-issue right applies the insurer may ask health questions, charge more, or decline her.

Ruth keeps working with employer coverage and delays Part B. She retires at 68 and her Part B coverage starts 1 September. Only then are both conditions true for the first time, so her window runs September through the end of February of the following year, at age 68. Her long employer coverage also counts as creditable coverage, so the six-month pre-existing-condition exclusion does not apply to her policy. Same birthday, same age at purchase, entirely different footing, and the difference is when Part B started.

What the window gives you

• Any policy the insurer sells, at the price a healthy applicant of the same age and location pays, whatever your medical history.
• The price protection as well as the issuance protection, which is what makes the guarantee worth having.
• A clean comparison: because benefits within a letter are standardized and health cannot affect the quote, the shopping problem reduces to price and the insurer's rating method.
• Prior creditable coverage carried into the policy, which for most people removes the pre-existing-condition exclusion outright.

Its limits

• It happens once. There is no annual reopening, and no penalty-free way back in after it closes.
• It can open at a moment the person is not thinking about supplements, such as when they sign up for Part B while still working.
• It does not stop a six-month benefit exclusion for a condition treated or diagnosed in the six months before the policy took effect, unless prior creditable coverage removes it.
• Federal law generally does not require insurers to sell to people under 65, so a beneficiary on Medicare through disability may have no federal window until 65.
• It says nothing about price increases later. A policy issued without underwriting can still be repriced along with everyone else's in the same rating class.