Medicare Supplement

Medicare Supplement basics for Centennial, Colorado

CENTENNIAL, Colo. — If you've ever tried to make sense of Medicare Supplement insurance, you know the alphabet can feel overwhelming. Plan A, Plan G, Plan N — what do the letters mean, and how do you know what any of them actually cover? Here's a plain-English guide to how Medigap works, what it pays for, and what it does not.

What Medigap actually is

Medicare Supplement Insurance — usually called Medigap — is private insurance you can buy to work alongside Original Medicare (Part A and Part B). Original Medicare pays a big share of your covered hospital and doctor bills, but it doesn't pay everything. You're still responsible for deductibles, coinsurance, and copays, and there is no annual out-of-pocket limit built into Original Medicare.

That's the "gap" Medigap is designed to fill. When you have a Medigap policy, Medicare pays its share of an approved claim first, and then your Medigap plan pays some or all of what's left, depending on the letter you chose.

Medigap is different from Medicare Advantage (Part C). You cannot have both at the same time — Medigap only works with Original Medicare.

How the standardized letters work

In most states, including Colorado, Medigap plans are standardized by the federal government. That means each lettered plan has the same core benefits no matter which insurance company sells it. A Plan G sold by one carrier covers the same basic services as a Plan G sold by another. What can differ is the monthly premium, the company's customer service, and how they set rates as you age.

The plans currently sold are labeled A, B, D, G, K, L, M, and N. (Plans C and F are still held by people who were eligible for Medicare before Jan. 1, 2020, but they aren't sold to newly eligible enrollees anymore.) Massachusetts, Minnesota, and Wisconsin standardize their plans differently.

Because the benefits are set by law, comparing Medigap plans really comes down to two questions: which letter fits how you use care, and which company offers a fair, stable price for that letter.

What Medigap generally helps with — and what it doesn't

Depending on the letter you pick, a Medigap policy may help cover things like:

• Part A hospital coinsurance and an extra 365 hospital days after Medicare benefits end
• Part B coinsurance or copays
• The first three pints of blood each year
• Hospice care coinsurance or copays
• Skilled nursing facility coinsurance
• The Part A deductible (most letters)
• Foreign travel emergency care (some letters, up to plan limits)

What Medigap does not cover is just as important. Medigap policies generally don't pay for prescription drugs, routine dental, vision, or hearing care, eyeglasses, hearing aids, long-term custodial care, or private-duty nursing. For prescriptions, you would enroll in a stand-alone Medicare Part D plan.

What's happening with drug coverage in 2026

Even though Medigap itself doesn't cover prescriptions, it's worth knowing how Part D is changing, because most Medigap enrollees pair the two.

In 2026, Part D has a $2,100 annual out-of-pocket cap on covered drugs — once you hit it, you pay $0 for the rest of the calendar year on covered medications. The maximum Part D deductible is $615. The old "donut hole" coverage gap was eliminated in 2025, so Part D now has three phases instead of four. Anyone enrolled in Part D can also opt into the Medicare Prescription Payment Plan, which spreads your drug costs into level monthly bills instead of hitting all at once at the pharmacy counter.

Higher-income enrollees may pay an IRMAA surcharge on Part B and Part D premiums; in 2026 that starts above $109,000 in income for a single filer.

Timing matters: the Medigap open enrollment window

The single most important date in Medigap is personal, not a national deadline. 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 history.

After that window closes, in most states insurers can use medical underwriting, which means health questions can affect whether you can switch plans or what you'll pay. There are some limited guaranteed-issue rights outside the initial window (for example, if certain coverage ends involuntarily), and a few states have extra protections. Colorado follows the federal framework.

Two other dates to know, though they apply to Medicare Advantage and Part D rather than Medigap: Medicare's Annual Enrollment Period runs Oct. 15 through Dec. 7, and Medicare Advantage Open Enrollment runs Jan. 1 through March 31.

Availability in and around Centennial

Centennial is in Arapahoe County, where multiple insurance companies are licensed to sell standardized Medigap policies. Because the benefits within each letter are set by federal rules, the shopping question locally is really about premiums and company service — not about which carrier "covers more." Colorado's Division of Insurance publishes rate information, and the State Health Insurance Assistance Program (SHIP) — known here as Colorado SHIP — offers free, unbiased help.