En español | Medicare’s open enrollment period (Oct. 15 to Dec. 7) is only for people who wish to change the regular Medicare coverage that they receive through the original Medicare program, a Medicare Advantage plan or a Part D prescription drug plan. It is not for people who wish to buy, or change, Medigap supplemental insurance, which is not a government program but private insurance that people can choose to buy separately to cover some of their out-of-pocket Part A and Part B expenses in original Medicare. 

(Note: The following information applies only to people with Medicare who are 65 or older. If you are under 65 and have Medicare on the basis of disability, the rules that determine your ability to buy or change Medigap policies depend on the laws of your state. Check with your state department of insurance.) 

Medigap policies can be bought, or changed, at any time of the year. But it is only at special times that you can buy a policy with federal protections known as “guaranteed issue.” These important protections prohibit insurance companies from denying coverage or charging higher premiums based on health status or preexisting conditions if you buy Medigap policies during certain periods. Outside of those periods, they can do both — unless you live in one of the few states that allow you to buy Medigap with guaranteed issue at any time of the year. 

The most common time for buying Medigap with guaranteed issue is within six months of your Medicare Part B coverage going into effect. (This six-month time frame is also referred to as “open enrollment” for Medigap, which is why it is often confused with Medicare’s open enrollment period.) 

But be careful. In most cases, this six-month period is a once-only opportunity.  So if you have employer coverage after age 65 — and that coverage is primary — but you still sign up for Part B at 65, you will not be entitled to this period of guaranteed issue if you want Medigap insurance after you retire.  

The exception here is if your employer insurance is secondary to Medicare — which it might be if the employer has fewer than 20 employees and requires you to sign up with Part B on turning 65. In this situation, you are entitled to federal protections when you retire, provided that you buy a Medigap policy within 63 days of the employer coverage ending. 

Other circumstances in which you can buy a Medigap policy with guaranteed issue include: 

• If you have any type of employer or union insurance that is secondary to Medicare (pays only for services that it covers but Medicare doesn’t), including retiree health benefits and COBRA coverage. (In this situation, you can buy a Medigap policy no later than 63 days after the date the coverage ends or you find out that the coverage has ended.)
• If you’re in a Medicare Advantage plan (such as an HMO or PPO) but move outside of its service area and you return to original Medicare instead of joining another Advantage plan. (No later than 63 days after the plan’s coverage ends.)
• If you’re in a Medicare Advantage plan that withdraws service from your area or closes down, and you return to original Medicare. (No later than 63 days after the plan’s coverage ends.)
• If you dropped a Medigap policy to join a Medicare Advantage plan, you can return to original Medicare and get your Medigap policy back on the same terms provided that this is the first Advantage plan you’re ever had and you’ve been in it for no longer than 12 months. (This first year in a Medicare Advantage plan counts as a trial period.)
• If you live in one of the few states that allow residents to buy Medigap policies with guaranteed issue at any time in any year or once a year during your birthday month. (Check state law with your state department of insurance.)

Note that if you have Medicare under age 65 due to disability, when you turn 65 you will be entitled to another six-month period to buy the Medigap policy of your choice with guaranteed issue. This is a legal right under federal law — regardless of whether you’ve had a Medigap policy before, or whether you already have Part B coverage, or where you live. This six-month period begins when you turn 65 and become eligible for Medicare based on age instead of disability.

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