Medicare Supplement

Frederick Medicare Supplement: What Each Plan Letter Covers

FREDERICK, Md. — If you've started shopping for a Medicare Supplement policy, you've probably noticed something curious: the plans are labeled with letters. Plan A, Plan B, Plan G, Plan N, and a few others. It can feel like alphabet soup, but there's a good reason behind it — and understanding the system can save you a lot of confusion.

Here's a plain-English guide to what Medigap does, how the letter system works, and where Frederick-area readers can turn for personalized help.

What Medigap Actually Does

Medicare Supplement Insurance — better known as Medigap — is private insurance that works alongside Original Medicare (Part A and Part B). It's designed to help pay some of the out-of-pocket costs that Original Medicare leaves behind, like coinsurance, copayments, and in some cases deductibles.

Medigap is not the same as a Medicare Advantage plan. Advantage plans (Part C) replace the way you get your Original Medicare benefits and often bundle in extras. Medigap, on the other hand, sits on top of Original Medicare — you keep your red, white, and blue card, and the Medigap policy picks up its share after Medicare pays first.

You cannot have both a Medicare Advantage plan and a Medigap policy at the same time.

Why the Letters Exist

Before 1990, Medigap policies varied wildly from one insurance company to the next, and shoppers had a hard time comparing them. Congress stepped in and required the plans to be standardized, meaning each lettered plan offers the exact same set of benefits, no matter which insurance company sells it.

In most states, including Maryland, Medigap plans are labeled A, B, C, D, F, G, K, L, M, and N. (Massachusetts, Minnesota, and Wisconsin have their own standardized systems.)

Here's the key point: Plan G from one company covers exactly the same core benefits as Plan G from another company. What can differ is the monthly premium, the company's customer service, and how they set future rate increases.

What the Letters Cover — In Broad Strokes

Each lettered plan covers a different combination of gaps in Original Medicare. Some cover almost everything; others cover less in exchange for a lower premium. Common benefits Medigap plans may help with include:

• Part A hospital coinsurance and extra hospital days
• Part B coinsurance or copayments
• The first three pints of blood
• Skilled nursing facility coinsurance
• Part A and Part B deductibles (varies by plan)
• Foreign travel emergency care (varies by plan)

Plan F and Plan C, which covered the Part B deductible, are no longer sold to people who became eligible for Medicare on or after January 1, 2020. If you were eligible before that date, you may still be able to buy them.

Medigap does not cover prescription drugs. For that, you'd need a separate Part D plan.

Where You Live Matters — a Little

Frederick is in Frederick County, where Medigap plans are regulated at the state level by the Maryland Insurance Administration. That means the letter definitions are the same you'd see anywhere else in Maryland, but the companies licensed to sell them — and the prices they charge — can vary.

Unlike Medicare Advantage and Part D, Medigap availability is not tied to a specific county-by-county service area in the same way. Still, premiums and underwriting rules can differ, so it pays to compare.

The Best Time to Buy

There's one timing rule every Medicare beneficiary should know: your Medigap Open Enrollment Period. It's a six-month window that starts the month you're 65 or older and enrolled in Part B.

During this window, insurance companies can't turn you down or charge you more based on your health. Outside of it, in most cases, they can — and often do — use medical underwriting. Missing this window is one of the most common and costly Medicare mistakes.

This is separate from the fall Annual Enrollment Period (October 15 – December 7), which is for Medicare Advantage and Part D changes, not Medigap.

A Quick Note on 2026 Costs

While Medigap itself doesn't change year to year in terms of what each letter covers, some of the underlying Medicare numbers do. For 2026, the Part D out-of-pocket cap is $2,100, and the Part D deductible can be as high as $615. The coverage gap, or "donut hole," has been eliminated as of 2025, replaced by a simpler three-phase drug benefit. IRMAA surcharges — extra premiums for higher-income beneficiaries — start above $109,000 for a single filer in 2026.

None of those figures come out of your Medigap policy, but they affect the bigger picture of what Medicare costs you overall.