Medicare Supplement

Medigap in Sioux Falls: which plan letters South Dakota lets you buy

If you live in Sioux Falls and you are pairing Original Medicare with a Medicare Supplement policy — what most people call Medigap — the first thing to know is that the letters on the shelf are set by federal rules, not by any one company. That means a Plan G from one insurer covers the same federally standardized benefits as a Plan G from another. What can differ is price, customer service, and how the company handles rate changes over time.

Medicare SupplementSioux Falls, SD

Sioux Falls sits in Minnehaha County, and the Medicare.gov Medigap policy search shows 27 insurers offering coverage in the local ZIP area, across Plans A, B, C, D, F, F-HD, G, G-HD, K, L and N.

What Medigap is (and what it is not)

Medigap is private insurance that helps pay some of the out-of-pocket costs Original Medicare leaves behind — things like the Part A hospital deductible, coinsurance, and Part B coinsurance. It does not replace Medicare. It rides alongside it.

A few points that trip people up:

• Medigap does not work with Medicare Advantage. If you have an Advantage plan, you cannot use a Medigap policy at the same time.
• Medigap does not include prescription drug coverage. You buy a separate Part D plan for that.
• Medigap does not usually cover dental, vision, hearing aids or long-term care.

The plan letters you can buy in South Dakota

South Dakota follows the federal standardized Medigap chart (only Massachusetts, Minnesota and Wisconsin use their own systems). For people newly eligible for Medicare today, that means these letters are on the shelf:

A, B, D, G, G-HD, K, L, M and N.

Plans C and F are still sold, but only to people who were eligible for Medicare before January 1, 2020. If you turned 65 or otherwise became eligible after that date, those two letters are closed to you by federal law.

Within each letter, benefits are identical from company to company. A Plan N sold by one carrier covers the same federally set items as a Plan N sold by another. That is what makes shopping the same letter across insurers a fair, apples-to-apples comparison.

How Medigap pairs with Part D

Because Medigap sold today does not include drug coverage, most Sioux Falls residents on Original Medicare pair it with a stand-alone Part D plan. A few 2026 program facts worth keeping in mind as you plan:

• Part D has a $2,100 annual out-of-pocket cap for 2026.
• The Part D deductible is capped at $615 for 2026 (plans may charge less).
• The old coverage gap, or "donut hole," has been eliminated as of 2025 — Part D now has three phases.
• The Medicare Prescription Payment Plan lets you spread your drug costs across the calendar year in level monthly amounts instead of paying them all at the pharmacy counter.
• IRMAA income surcharges on Part B and Part D begin above $109,000 for a single filer in 2026.

Who sells Medigap in the Sioux Falls area

Twenty-seven insurers show up in the Medicare.gov search for a Sioux Falls ZIP (57103). They range from national names to South Dakota–based carriers. Rather than repeat the whole list here, the table below shows every insurer and the letters each one offers. A few examples of the range you will see:

• Some carriers offer nearly every letter — for instance, AARP - UnitedHealthcare Insurance Company, Humana (Humana Insurance Company) and United American Insurance Company each list a broad menu.
• Some focus on a narrower set — Heartland National Life Insurance Company lists Plans A, G and N; South Dakota Farm Bureau Health Plans lists A, D, G and N.
• Regional carriers active in the state include Avera Health Plans, Inc. and Wellmark BlueCross BlueShield of South Dakota.

Because benefits within a letter are the same, what you are really comparing between companies is price, rate history, and how each one treats customers over time.

The state rules that shape your choice

Two federal rules matter most when you first sign up:

• Medigap Open Enrollment. The one-time, 6-month window that starts the month your Part B is effective and you are 65 or older. During this window, any insurer selling Medigap in South Dakota must sell you a policy at their standard rate, regardless of your health.
• Guaranteed issue rights. Federal law gives you the right to buy certain Medigap plans without medical underwriting in specific situations — for example, if your Medicare Advantage plan leaves the area, or your employer coverage ends.

Outside those windows, South Dakota generally allows insurers to use medical underwriting, which means they can ask health questions and decide whether to offer you a policy and at what rate. Some states have added extra rights (like "birthday rules" that let you switch each year without underwriting); whether South Dakota adds any protections beyond federal law is a question best answered by the South Dakota Division of Insurance or your local SHIINE counselor (South Dakota's State Health Insurance Assistance Program, or SHIP).

How to compare without getting lost

A simple approach that works for most people:

1. Pick the letter first (A, B, D, G, G-HD, K, L, M or N) based on how much cost-sharing you want to hand off to the insurer. 2. Then compare that same letter across the insurers in the table below. 3. Ask each insurer how often they have raised rates in South Dakota, and how they calculate premium changes as you age. 4. Add a stand-alone Part D plan to cover your prescriptions.