Medicare Supplement

Medigap, Explained: What Those Plan Letters Really Mean

ESSEX JUNCTION, Vt. — If you've ever looked at Medicare Supplement insurance — also called Medigap — and felt confused by all the letters, you're not alone. Plans labeled A, B, D, G, K, L, M, and N sound like an eye chart, not health coverage. But there's a logic behind them, and once you understand what Medigap is designed to do, the letters get a lot easier to sort out.

Making sense of Medicare Supplement insurance

Here's a plain-language guide to how Medigap works, what it covers, and what it doesn't.

What Medigap is (and isn't)

Medigap is private insurance you can buy to help pay some of the out-of-pocket costs that Original Medicare — Part A (hospital) and Part B (medical) — leaves behind. Think of costs like the Part A hospital deductible, Part B coinsurance, and certain hospital charges after Medicare's coverage runs out.

A Medigap policy only works alongside Original Medicare. It does not work with a Medicare Advantage (Part C) plan. You cannot have both at the same time.

A few other things Medigap generally does not cover:

• Prescription drugs (you'd need a separate Part D plan)
• Routine dental, vision, or hearing care
• Long-term care, like a nursing home stay
• Private-duty nursing

Why the standardized letters exist

Since 2010 in most states, Medigap plans have been standardized by the federal government. That means a Plan G sold by one company covers the same core benefits as a Plan G sold by another company. The price and customer service can differ, but the benefits inside each lettered plan are set by law.

That standardization is meant to make shopping easier. You're comparing apples to apples on benefits, and then looking at price, company reputation, and how the insurer handles rate increases over time.

The currently sold plans are A, B, D, G, K, L, M, and N. Plans C and F are still held by people who had them before, but they're no longer sold to people who became eligible for Medicare on or after January 1, 2020, because those plans covered the Part B deductible.

Vermont is one of a handful of states (along with Massachusetts, Minnesota, and Wisconsin) with its own approach to standardizing Medigap. Vermonters should check with the state's insurance department or their local SHIP counselor for details specific to plans sold here.

What the letters generally cover

Every standardized Medigap plan covers a core set of benefits, including Part A coinsurance and hospital costs for an extra 365 days after Medicare benefits end. From there, the letters add different pieces:

• Plan A — the most basic set of benefits.
• Plan B — adds the Part A deductible.
• Plan G — one of the most comprehensive plans available to newly eligible enrollees; it covers nearly everything except the Part B deductible.
• Plans K and L — cost-sharing plans that pay a percentage (K pays 50%, L pays 75%) of certain costs, with an annual out-of-pocket limit.
• Plan M — covers half of the Part A deductible.
• Plan N — covers Part B coinsurance but may leave small copays for office visits and emergency room trips.

For the full official benefit chart, see the "Compare Medigap plan benefits" tool on medicare.gov.

When you can buy a Medigap policy

Timing matters more with Medigap than many people realize. Your Medigap Open Enrollment Period 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 can't turn you down or charge you more because of your health.

Outside that window, in most states, insurers can use medical underwriting. That means they can look at your health history and decide whether to sell you a policy and at what price. Some states have extra protections, so it's worth checking Vermont's rules if you're considering switching later.

How this fits with the rest of Medicare in 2026

Medigap sits alongside a few other 2026 Medicare updates worth knowing:

• Part D prescription drug plans have a new $2,100 out-of-pocket cap for covered drugs.
• The Part D maximum deductible is $615.
• The old coverage gap, or "donut hole," is gone — Part D now has three phases.
• The Medicare Prescription Payment Plan lets you spread drug costs across the year in monthly amounts, if you choose to opt in.
• IRMAA income-related surcharges for Part B and Part D start above $109,000 for a single filer in 2026.
• The Annual Enrollment Period for Part D and Medicare Advantage runs October 15 – December 7. Medicare Advantage Open Enrollment runs January 1 – March 31.

Medigap does not follow the October-to-December calendar the way Part D and Advantage do — you can apply for a Medigap policy at other times of year, but medical underwriting may apply outside your open enrollment window or a guaranteed-issue situation.

What availability looks like around Essex Junction

Essex Junction is in Chittenden County, where residents can look at both Medicare Advantage plans and Medigap policies. Availability of specific Medigap plan letters and the companies that offer them is set at the state and county level. Medicare's Plan Finder at medicare.gov will show which policies are offered where you live.