Medicare Supplement

What Medicare Supplement covers alongside Original Medicare in Killeen

KILLEEN, Texas — If you're new to Medicare, or helping a parent sort it out, you've probably run into the word "Medigap." It sounds like jargon, but the idea is simple: Original Medicare doesn't pay for everything, and Medigap is one way to help cover what's left.

Here's a plain-English look at what Medicare Supplement insurance does, what the lettered plans mean, and how to think through the choice.

What Medigap actually does

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

A few things to know up front:

• Medigap only works with Original Medicare. You can't use it with a Medicare Advantage plan.
• Medigap does not include prescription drug coverage. If you go the Medigap route, you'll usually add a stand-alone Part D drug plan.
• It doesn't cover long-term care, dental, vision, or hearing aids.
• You pay a monthly premium to the Medigap insurer, on top of your Part B premium.

For the official basics, Medicare.gov's Medigap section is the source of truth.

How the standardized letters work

Medigap plans are standardized by the federal government. That means a Plan G sold by one company covers the same Medicare-approved costs as a Plan G sold by another company. The letters — A, B, C, D, F, G, K, L, M, and N — describe the level of coverage.

A few highlights of how the letters differ:

• Plans A and B cover a core set of benefits, like Part A coinsurance and Part B coinsurance.
• Plan G is one of the more comprehensive options available to people newly eligible today. It covers most gaps except the Part B deductible.
• Plan N typically has lower premiums but asks you to pay small copays for some office and ER visits.
• Plans K and L have lower premiums and use cost-sharing with an annual out-of-pocket limit.
• Plans C and F 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.

Massachusetts, Minnesota, and Wisconsin standardize their Medigap plans differently, but in Texas the federal lettered plans apply.

The enrollment window that matters most

The single most important date in Medigap isn't in the fall — it's your Medigap Open Enrollment Period. It's 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 "guaranteed issue" rights. Insurers can't turn you down or charge you more because of your health history. Miss it, and outside of a few special situations, insurers in most states can use medical underwriting — meaning your health can affect whether you're accepted and what you pay.

That's a big deal, and it's often where people trip up.

How Medigap compares to Medicare Advantage

Medigap and Medicare Advantage are two different paths, not two flavors of the same thing.

• Original Medicare + Medigap + Part D: You can see any provider in the U.S. who accepts Medicare. You pay a monthly Medigap premium, and your remaining out-of-pocket costs are usually more predictable.
• Medicare Advantage: A private plan that bundles Part A, Part B, and usually Part D, often with extra benefits. Plans have networks and their own rules.

Killeen is in Bell County, where a range of Medicare Advantage and stand-alone Part D plans are offered each year — but Medigap availability is a separate question handled through private insurers licensed in Texas. Neither path is universally better; it depends on your doctors, your prescriptions, your budget, and how you feel about networks versus premiums.

A few 2026 program facts worth knowing

Even if you go with Medigap, the rest of Medicare still applies to you:

• Part D has a new $2,100 out-of-pocket cap on covered drugs for 2026.
• The Part D maximum deductible is $615 in 2026.
• The old coverage gap (the "donut hole") was eliminated in 2025; Part D now has three phases.
• The Medicare Prescription Payment Plan lets you spread drug costs across the year in monthly installments if you choose.
• IRMAA — income-related surcharges on Part B and Part D — begin above $109,000 in income for a single filer in 2026.
• Annual Enrollment runs October 15 – December 7. Medicare Advantage Open Enrollment runs January 1 – March 31. Neither of these is your Medigap window.