Medicare Supplement

Why Medigap Letters Are Standardized in Round Rock

ROUND ROCK, Texas — If you're new to Medicare, or helping a parent sort through the mail piling up on the kitchen table, you've probably seen the words "Medicare Supplement" and "Medigap" used side by side. They mean the same thing. And once you understand what Medigap does — and just as importantly, what it doesn't do — the rest of your Medicare choices get a lot easier to think through.

Here's a plain-English guide to how Medigap works, how the standardized letter plans are set up, and the small mistakes that can cost people real money.

What Medigap actually is

Medigap is private insurance that helps pay some of the costs Original Medicare leaves behind — things like the Part A hospital deductible, the Part B 20% coinsurance, and other out-of-pocket amounts.

It only works alongside Original Medicare (Part A and Part B). You can't use a Medigap policy with a Medicare Advantage plan. That's one of the biggest points of confusion, so it's worth repeating: Medigap fills gaps in Original Medicare. It is not an add-on to Medicare Advantage.

Medigap also does not cover prescription drugs. For that, most people with Original Medicare add a stand-alone Part D drug plan.

How the standardized letter plans work

Medigap plans are labeled by letter: 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.)

Here's the part that surprises people: within each letter, the benefits are standardized by federal law. A Plan G sold by one company covers the same things a Plan G sold by another company covers. What changes between companies is the price, the customer service, and sometimes extras like a gym benefit.

That means shopping Medigap is mostly about:

• Picking the letter that matches how much cost-sharing you want to handle yourself, and
• Comparing prices among the companies that sell that letter in Texas.

Massachusetts, Minnesota, and Wisconsin standardize their plans a little differently, but Texans use the standard letter system.

The enrollment window that matters most

Under federal rules, you get a Medigap Open Enrollment Period that lasts six months and starts the month you're 65 or older and enrolled in Part B. During that window, insurers can't turn you down or charge you more because of your health.

Miss that window, and in most states — Texas included — companies can use medical underwriting. That means they can ask health questions, and they can decline you or raise the price. This is the single most common Medigap mistake: waiting, then trying to buy later after a health issue shows up.

There are a few special situations (called "guaranteed issue rights") that reopen protections, such as losing certain coverage through no fault of your own. But the safest path is enrolling during that first six-month window.

What Medigap doesn't cover

Even a generous Medigap plan won't help with:

• Prescription drugs — you need a Part D plan for that.
• Routine dental, vision, or hearing care.
• Long-term care in a nursing home.
• Hearing aids, eyeglasses, or private-duty nursing.

For 2026, it's also worth knowing what's changing on the drug side, since drug costs sit outside Medigap. Part D has a new $2,100 annual out-of-pocket cap, a maximum deductible of $615, and the old "donut hole" coverage gap is gone — replaced with a simpler three-phase design. Medicare's optional Prescription Payment Plan lets you spread your drug costs across the year in monthly amounts instead of paying big bills at the pharmacy counter.

Higher-income beneficiaries may also owe IRMAA surcharges on Part B and Part D; for a single filer in 2026, those begin above $109,000 in income.

How Medigap fits with the rest of Medicare in Round Rock

Round Rock is in Williamson County, where residents choose between two broad paths: Original Medicare (often paired with a Medigap plan and a Part D drug plan), or a Medicare Advantage plan that bundles hospital, medical, and usually drug coverage together. Medicare Advantage plan availability is set at the county level, so what's offered in Williamson County may differ from a neighboring county.

Neither path is universally "better." Medigap tends to appeal to people who want predictable out-of-pocket costs and the freedom to see any provider nationwide that accepts Medicare. Medicare Advantage appeals to people who like bundled extras and a network-based structure. The right fit depends on your doctors, your medications, your travel patterns, and your budget.

Remember the calendar:

• Annual Enrollment Period: October 15 – December 7 (for Part D and Medicare Advantage changes).
• Medicare Advantage Open Enrollment: January 1 – March 31.
• Medigap Open Enrollment: the six months starting when you're 65 and enrolled in Part B — a one-time window for most people.