Medicare Supplement

How Medigap Standardization Works for Louisville Medicare

LOUISVILLE, Ky. — If you've spent any time reading about Medicare, you've probably run into a wall of letters: Plan A, Plan G, Plan N, Plan K. Those letters belong to Medicare Supplement Insurance, better known as Medigap. And while the alphabet soup can feel overwhelming, the system is actually built to make comparing coverage easier — not harder — once you know how it works.

Here's a plain-English walk-through for Louisville residents who want to understand what Medigap does, what the letters mean, and the common mistakes to sidestep.

What Medigap actually does

Medigap is private insurance that works alongside Original Medicare (Part A and Part B). It doesn't replace Medicare — it helps pay some of the out-of-pocket costs Original Medicare leaves behind, like coinsurance, copayments, and in some cases the Part A deductible.

A few key points to keep straight:

• Medigap only works with Original Medicare. If you're enrolled in a Medicare Advantage plan, you generally can't use a Medigap policy at the same time.
• Medigap does not include prescription drug coverage. For medications, you'd typically add a separate Part D plan.
• You pay a monthly premium for Medigap on top of your Part B premium.

Why the plans come in letters

Medigap plans are standardized by federal law in most states. That means Plan G sold by one insurance company covers the exact same benefits as Plan G sold by another. The letter tells you what's covered. The insurance company sets the price and handles customer service, but they can't change what the plan includes.

There are ten standardized letter plans currently offered: 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.) Kentucky follows the standard federal framework, so what you see on paper in Louisville is what you'd see in most other states.

This standardization is the reason Medigap shopping is different from shopping for other insurance. You're not really comparing benefits company-to-company — you're comparing price and service for the same benefit package.

The best time to enroll (and why timing matters)

The single most important date in Medigap is the start of your Medigap Open Enrollment Period. It begins the month you're 65 or older and enrolled in Part B, and it lasts six months.

During that window, you have what's called guaranteed issue rights. Insurance companies must sell you any Medigap policy they offer at their best available rate, regardless of your health history. Miss that window, and in most cases insurers can use medical underwriting — meaning they can charge more or decline coverage based on your health.

This is where a lot of people trip up. If you delay enrolling in Medigap because you feel healthy, you may not get the same access later. Louisville is in Jefferson County, and the rules here follow the same federal timing framework.

How Medigap fits with Part D and Medicare Advantage

Medigap and Medicare Advantage are two different roads. You pick one:

• Original Medicare + Medigap + a Part D drug plan. More predictable out-of-pocket costs, broad provider access, but you'll pay Medigap premiums.
• Medicare Advantage. Bundles hospital, medical, and usually drug coverage through a private plan, often with network rules.

For 2026, Part D has a hard out-of-pocket cap of $2,100 for covered drugs, and the maximum Part D deductible is $615. The old "donut hole" coverage gap was eliminated in 2025, so drug coverage now moves through three phases instead of four. If monthly drug costs are a strain, ask about the Medicare Prescription Payment Plan, which spreads your yearly drug costs into monthly installments.

Higher earners should also know about IRMAA — an income-related surcharge on Part B and Part D premiums that kicks in above $109,000 for single filers in 2026.

Common Medigap mistakes to avoid

• Assuming all Plan Gs are different. They're not. The benefits are identical by law. Compare price and the company's reputation.
• Waiting past your six-month open enrollment window. Health underwriting can change everything.
• Confusing Medigap with Medicare Advantage. They're separate products with separate rules — and you generally can't hold both.
• Forgetting about drug coverage. Medigap doesn't include Part D. You need to plan for that separately.
• Not revisiting your Part D each fall. The Annual Enrollment Period runs October 15 – December 7, and drug plans change every year.