Medicare Supplement

How standardized Medigap letters function in Brookings

BROOKINGS, S.D. — If you've been reading about Medicare and keep bumping into terms like "Plan G," "Plan N," or "Medigap Plan K," you're not alone. Medicare Supplement insurance — usually called Medigap — is one of the most misunderstood pieces of the Medicare puzzle. Here's a plain-language look at what it does, what it doesn't, and how those standardized letter plans actually work.

What Medigap is (and isn't)

Medigap is private insurance that helps pay some of the out-of-pocket costs Original Medicare (Part A and Part B) leaves behind — things like coinsurance, copayments, and deductibles. It's designed to work alongside Original Medicare, not replace it.

A few important points:

• Medigap is not Medicare Advantage. Medicare Advantage (Part C) is a different way to get your Medicare benefits, and you can't have both a Medigap policy and a Medicare Advantage plan at the same time.
• Medigap doesn't include prescription drug coverage. If you want help with drug costs, you'll need a separate Part D plan.
• Medigap doesn't cover long-term care, most dental, vision, hearing aids, or private-duty nursing.

If you live in Brookings, you'd buy a Medigap policy from a private insurer licensed in South Dakota. Availability of specific carriers and pricing varies, but the plans themselves are standardized across most states.

How the letter plans work

Here's where a lot of the confusion comes in. In most states — South Dakota included — Medigap plans are standardized by the federal government and labeled with letters: A, B, C, D, F, G, K, L, M, and N.

The key idea: Plan G from one company covers the same basic benefits as Plan G from another company. The letter tells you what's covered. The company you buy from sets the price and the customer service experience.

That means when you're comparing Medigap policies, you're really comparing:

1. Which letter plan fits your needs, and 2. Which insurer offers it at a fair price with good service.

Plans C and F are only available to people who became eligible for Medicare before January 1, 2020. If you turned 65 after that date, those two are off the table for you.

What the letters actually cover

Every standardized Medigap plan covers at least a core set of benefits, including Part A hospital coinsurance and an extra year of hospital coverage after Medicare benefits are used up. From there, plans differ in how much they cover for things like:

• Part B coinsurance and copays
• The first three pints of blood
• Skilled nursing facility coinsurance
• Part A and Part B deductibles
• Foreign travel emergency care (up to plan limits)

Some plans (like K and L) cover a percentage of certain costs rather than 100%, and they include a yearly out-of-pocket limit. Plan N has small copays for some office and emergency room visits.

Medicare.gov publishes a side-by-side chart of what each letter covers — it's the clearest way to compare before you shop.

The best time to buy — and why it matters

The single biggest mistake people make with Medigap is missing their Medigap Open Enrollment Period. This is a six-month window that starts the month you're 65 or older and enrolled in Part B.

During that window, you have a guaranteed right to buy any Medigap policy sold in your state, at the best available rate, regardless of your health history. Insurers can't turn you down or charge you more because of a pre-existing condition.

After that six months? In most cases, insurers can use medical underwriting. That means they can ask health questions, charge more, or even deny coverage. A few limited "guaranteed issue" situations exist later on, but they're the exception.

If you're approaching 65 in Brookings, mark that window on your calendar. It doesn't come back.

How Medigap fits with the rest of Medicare

A common setup looks like this:

• Part A + Part B (Original Medicare) — your foundation.
• A Medigap policy — helps cover the gaps in Parts A and B.
• A stand-alone Part D plan — for prescription drugs.

For 2026, Part D has some important updates worth knowing: the out-of-pocket cap for covered drugs is $2,100, the maximum Part D deductible is $615, and the old "donut hole" coverage gap has been eliminated (Part D now has three phases instead of four). There's also the optional Medicare Prescription Payment Plan, which lets you spread your drug costs across the year in monthly payments.

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

Brookings is in Brookings County, where Medicare Advantage and Part D plan availability is set at the county level. If you're weighing Medigap versus Medicare Advantage, county-level plan counts matter for the Advantage side — but the Medigap letter plans themselves are the same statewide.