Medicare Supplement

Understanding Medigap: How the Plan Letters Actually Work

PORTLAND, Maine — If you've ever tried to shop for a Medicare Supplement plan, you've probably run into a wall of letters: Plan A, Plan G, Plan N, Plan K. It can feel like alphabet soup. But those letters actually make your life easier once you know what they mean. Here's a plain-language guide to how Medigap works and what the standardized letters really tell you.

What Medigap does (and doesn't do)

Medigap — the nickname for Medicare Supplement Insurance — is a private policy you can buy to help pay some of the costs Original Medicare (Part A and Part B) leaves behind. That includes things like coinsurance, copayments, and in some cases the Part A deductible.

A few important points from Medicare.gov:

• Medigap only works with Original Medicare. It does not work with Medicare Advantage.
• Medigap does not cover prescription drugs. For that, you'd add a separate Part D plan.
• Medigap does not cover long-term care, dental, vision, hearing aids, or private-duty nursing.
• You pay a monthly premium to the insurance company on top of your Part B premium.

Think of it as a cushion for the gaps in Original Medicare — hence the name.

Why the letters exist

Here's the part that trips people up. In most states, Medigap plans are standardized by the federal government. That means Plan G sold by one company covers the exact same benefits as Plan G sold by another company. The letter defines the benefits.

What can differ between companies?

• The monthly premium
• Customer service and how the company handles claims
• Extras some carriers throw in (like gym memberships), which aren't part of the standardized benefits

So the letter tells you what's covered. The company you buy from affects what you pay and how you're treated.

Massachusetts, Minnesota, and Wisconsin have their own standardized systems — but Maine follows the federal lettering.

The letters you'll see

Today, new enrollees can generally choose from these plans: A, B, D, G, K, L, M, and N. There's also a high-deductible Plan G and a high-deductible Plan F.

A few notes worth knowing:

• Plans C and F are no longer available 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.
• Plan G has become the most comprehensive option available to newly eligible enrollees.
• Plans K and L have lower premiums but include out-of-pocket limits and cost-sharing.
• Plan N typically has lower premiums than Plan G but may include small copays for office and ER visits.

Every plan with the same letter covers the same core benefits, no matter which company sells it. That's the whole point of standardization — you can compare on price and service instead of decoding fine print.

The best time to buy: your Medigap Open Enrollment Period

This is where people make expensive mistakes, so please read carefully.

Your Medigap Open Enrollment Period is a one-time, 6-month window that starts the month you're 65 and enrolled in Part B. During this window:

• You have a guaranteed issue right — insurers must sell you any Medigap policy they offer.
• They can't charge you more or turn you down because of health problems.

Outside of that window, in most states insurers can use medical underwriting. That means they can ask about your health, charge you more, or deny coverage entirely. Maine has some additional consumer protections, but the safest bet is to make your Medigap decision during that initial 6-month window.

Medigap vs. Medicare Advantage — not the same thing

This is another common mix-up. You cannot have both a Medigap policy and a Medicare Advantage plan. They're two different roads:

• Original Medicare + Medigap (+ Part D): You use your red, white, and blue Medicare card at any provider that accepts Medicare. Medigap helps pay your share.
• Medicare Advantage (Part C): A private plan that replaces how you get your Original Medicare benefits, usually with a network and often bundled with drug coverage.

Portland is in Cumberland County, and, as with the rest of Maine, residents can choose between Original Medicare (with or without Medigap) and the Medicare Advantage plans offered in the county. Which path fits depends on your doctors, your medications, your budget, and how much predictability you want.

A quick note on 2026 numbers

Even if you have Medigap, drug coverage is separate. For 2026, a few Part D facts to keep in mind:

• The Part D out-of-pocket cap is $2,100.
• The Part D maximum deductible is $615.
• The old coverage gap (“donut hole”) has been eliminated since 2025 — Part D now has three phases.
• The Medicare Prescription Payment Plan lets you spread your drug costs across the year in monthly amounts if that helps your budget.
• IRMAA surcharges (higher premiums for higher incomes) begin above $109,000 for a single filer in 2026.