Medicare Supplement

The Standardized Medigap Plans Available in Brookings

BROOKINGS, S.D. — If you've ever tried to make sense of Medicare Supplement Insurance, you've probably run into a wall of letters: Plan A, Plan G, Plan N, and so on. It looks confusing, but there's actually a tidy system behind it. Here in Brookings, where many neighbors are aging into Medicare each year, understanding those letters can take a lot of stress out of the process.

A quick word from Brookings

This guide explains what Medigap does, how the standardized letters work, and where to get personalized help.

What Medigap actually does

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

A few important points from Medicare.gov:

• You must have Part A and Part B to buy a Medigap policy.
• Medigap only works with Original Medicare. It does not work with Medicare Advantage.
• Medigap policies do not include prescription drug coverage. For that, you'd add a separate Part D plan.
• Each Medigap policy covers one person. Spouses need their own policies.

How the standardized letters work

In most states, Medigap plans are standardized by the federal government. That means a Plan G sold by one company covers the same basic benefits as a Plan G sold by another company. The letters — A, B, C, D, F, G, K, L, M, and N — each represent a different mix of benefits.

A few key rules to know:

• Plans C and F are only available to people who were eligible for Medicare before January 1, 2020.
• Plans K and L have out-of-pocket limits, after which the plan pays 100% of covered costs for the rest of the year.
• Massachusetts, Minnesota, and Wisconsin standardize their Medigap plans a bit differently.

Because benefits within a letter are the same across companies, the differences usually come down to price, customer service, and how the company handles rate increases over time.

When you can buy a Medigap policy

The best window to buy Medigap is 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:

• Companies can't turn you down for health reasons.
• They can't charge you more because of past or current health problems.

Outside that window, insurers in most states can use medical underwriting, which may affect whether you can get a policy or what you'll pay. Some states have extra protections — a local counselor can walk you through South Dakota's specific rules.

Brookings and county-level availability

Medigap is regulated at the state level, and availability isn't tied to your county the way Medicare Advantage and Part D plans are. Brookings is in Brookings County, where residents can shop Medigap policies offered statewide in South Dakota. To see which insurance companies sell Medigap in South Dakota, Medicare.gov has a plan finder tool that lists policies by ZIP code.

If you also want a Part D drug plan or Medicare Advantage plan, those are set at the county level, and the options in Brookings County may differ from other South Dakota counties.

A few 2026 numbers worth knowing

Even if you're focused on Medigap, these program-level figures for 2026 are helpful context:

• Part D out-of-pocket cap: $2,100 for the year.
• Part D maximum deductible: $615.
• The old coverage gap (the "donut hole") is gone as of 2025 — drug coverage now has three phases.
• The Medicare Prescription Payment Plan lets you spread drug costs across the year in monthly payments.
• IRMAA surcharges (extra premiums for higher earners) begin above $109,000 in income for a single filer in 2026.
• Annual Enrollment Period: Oct. 15 – Dec. 7. Medicare Advantage Open Enrollment: Jan. 1 – March 31.