Medicare Supplement

How Medigap's Letter Plans Work — and Why It Matters

MANCHESTER, N.H. — If you're new to Medicare, the alphabet soup of Medigap plans can feel confusing. Plan A, Plan G, Plan N — what do the letters mean, and why do they matter? The good news: Medicare Supplement Insurance (Medigap) is one of the more predictable corners of Medicare, thanks to a system of standardized plans set by federal law.

Here's a plain-English guide to what Medigap does, how the letters work, and the mistakes to avoid when you're comparing your options in Manchester and across Hillsborough County.

What Medigap actually does

Medigap is private insurance that works alongside Original Medicare (Part A and Part B). It helps pay some of the out-of-pocket costs that Original Medicare leaves behind — things like coinsurance, copayments, and deductibles.

A few important points to keep in mind:

• Medigap only works with Original Medicare. You cannot use a Medigap policy with a Medicare Advantage plan.
• Medigap does not include prescription drug coverage. For that, you'd add a separate Part D plan.
• You pay a monthly premium to the private insurer, in addition to your Part B premium.

Why the letters are "standardized"

Since 1990, federal law has required Medigap plans to be standardized. That means Plan G sold by one company covers exactly the same Medicare-approved benefits as Plan G sold by another company. The letter tells you the benefit package.

In most states, including New Hampshire, Medigap plans are labeled with letters: A, B, C, D, F, G, K, L, M, and N. (Massachusetts, Minnesota, and Wisconsin use their own systems.)

Because the benefits within a letter are identical from company to company, the main differences among insurers offering the same letter plan are:

• The monthly premium
• Customer service and billing experience
• How the company sets future rate increases

What each letter covers (in broad strokes)

Every standardized Medigap plan covers a core set of benefits, including Part A hospital coinsurance. From there, plans layer on additional coverage. For example:

• Plan A covers the basics.
• Plans K and L share costs with you up to an annual out-of-pocket limit.
• Plan N has some copays for office and emergency room visits.
• Plan G is one of the more comprehensive options available to people newly eligible today.

Two plans — Plan C and Plan F — cover the Part B deductible, but they're only available to people who became eligible for Medicare before January 1, 2020. If you turned 65 after that date, those two letters are off the table for you.

For the official side-by-side chart, see the Medigap section at medicare.gov.

Timing matters — a lot

The single biggest Medigap mistake people make is missing their Medigap Open Enrollment Period. This is a one-time, six-month window that starts the month you're 65 or older and enrolled in Part B.

During that window, you have a "guaranteed issue" right. Insurers must sell you any Medigap plan they offer, at their best available rate, and they cannot turn you down or charge you more because of your health history.

Outside that window, in most states insurers can use medical underwriting — meaning they can review your health and either deny coverage or charge higher premiums. New Hampshire has some additional protections in certain situations, but the safest bet is to understand your rights before your window closes.

How this looks locally

Manchester is in Hillsborough County, where residents on Original Medicare can shop Medigap plans offered by insurers licensed in New Hampshire. Because the letters are standardized, the shopping comparison is mostly about price and the company behind the policy — not the benefit list.

If you're weighing Original Medicare plus Medigap against a Medicare Advantage plan, that's a bigger decision that involves how you like to access care, whether you travel, and how you handle prescription drug coverage. A licensed counselor at New Hampshire's State Health Insurance Assistance Program (SHIP), called ServiceLink, can walk you through it at no cost.

Common mistakes to avoid

• Assuming Medigap covers drugs. It doesn't. You'll need a separate Part D plan.
• Waiting past your six-month open enrollment window. You may lose your guaranteed right to buy.
• Thinking a higher-priced Plan G is "better" than a lower-priced Plan G. The benefits are identical by law.
• Trying to use Medigap with a Medicare Advantage plan. It's not allowed.