Medicare Supplement

Medigap in Nashville: covering what Original Medicare leaves

NASHVILLE, Tenn. — If you've ever looked at a Medicare Summary Notice and wondered who pays the leftover 20%, you've bumped into the reason Medicare Supplement insurance exists. Also called Medigap, these policies help pay some of the out-of-pocket costs Original Medicare leaves behind. Here's a plain-English guide to what Medigap does, what it doesn't, and how those confusing letter names actually work.

What Medigap is — and what it isn't

Medigap is private insurance that works alongside Original Medicare (Part A and Part B). After Medicare pays its share of a covered service, your Medigap plan picks up some or all of what's left — things like coinsurance, copayments, and, depending on the plan, the Part A hospital deductible.

A few things Medigap is not:

• It is not Medicare Advantage. Medicare Advantage (Part C) replaces how you get your Original Medicare benefits; Medigap adds to Original Medicare. You can't have both at the same time.
• It doesn't include prescription drug coverage. For that, you'd add a separate Part D plan.
• It generally doesn't cover dental, vision, hearing aids, or long-term care.

For the official rundown, see Medicare's basics page at medicare.gov.

How the standardized letters work

Here's the part that trips people up. Medigap plans are sold by private insurance companies, but the benefits inside each lettered plan are set by federal law. That means Plan G from one company covers the exact same medical benefits as Plan G from another company. The price and the customer service can differ — the covered benefits cannot.

The plans currently sold are labeled with letters: A, B, C, D, F, G, K, L, M, and N. (Plans C and F are only available to people who became eligible for Medicare before January 1, 2020.) Each letter represents a different mix of coverage. Some cover nearly everything Original Medicare leaves behind; others use cost-sharing to keep the premium lower.

Because the benefits are standardized, comparing Medigap policies really comes down to three questions:

1. Which letter plan matches how much cost-sharing you want to handle yourself? 2. What does each insurance company charge for that same lettered plan? 3. How does the company price its plans as you age (community-rated, issue-age, or attained-age)?

The enrollment window that matters most

The single biggest Medigap mistake is missing your Medigap Open Enrollment Period. This is a one-time, six-month window that starts the month you're 65 and enrolled in Part B. During this window, you have a guaranteed right to buy any Medigap plan sold in Tennessee, at the best available rate, regardless of your health history.

Outside that window, insurers in most states — including Tennessee — can use medical underwriting. That means they can charge you more, or turn you down, based on your health. There are a few limited "guaranteed issue" situations later on, but the six-month window at 65 is the cleanest shot most people get.

Note this is different from the Medicare Annual Enrollment Period (Oct. 15 – Dec. 7) and the Medicare Advantage Open Enrollment Period (Jan. 1 – March 31). Those windows are for Part D and Medicare Advantage — not Medigap.

Medigap and drug coverage: keep them separate

Medigap policies sold today do not include prescription drug coverage. If you go the Original Medicare + Medigap route, you'll usually pair it with a stand-alone Part D drug plan.

A few 2026 Part D facts worth knowing:

• The Part D out-of-pocket cap is $2,100 in 2026. Once you hit it, you pay $0 for covered drugs the rest of the year.
• The maximum Part D deductible is $615.
• The old "donut hole" coverage gap was eliminated in 2025; Part D now has three phases.
• The Medicare Prescription Payment Plan lets you spread your drug costs across the year in monthly installments instead of paying big bills at the pharmacy counter.

How this looks in Nashville

Nashville sits in Davidson County, and plan availability in Medicare is set at the county level. Medigap itself isn't sold as county-specific "plans" the way Medicare Advantage is — the lettered plans available in Tennessee are the same statewide. What varies locally is which insurance companies choose to sell here and how they price each lettered plan for your age and ZIP code.

If you want to see what's offered, Medicare's Plan Finder at medicare.gov lets you search Medigap policies by ZIP code and shows the companies licensed to sell each lettered plan.

Common mistakes to avoid

• Assuming Medigap covers drugs. It doesn't. You'll need a Part D plan for that.
• Waiting past your six-month Medigap Open Enrollment. After it closes, insurers can underwrite.
• Comparing letters instead of prices. Once you've picked a letter, the benefits are identical across companies — so shop the premium and the company's reputation.
• Confusing Medigap with Medicare Advantage. They're different products with different rules; you can't be enrolled in both at once.