Medicare Advantage

Medigap Plan Letters in 2027: A Rapid City Guide

RAPID CITY, S.D. — If you've spent any time looking at Medicare Supplement Insurance — the coverage most people call Medigap — you've probably run into a wall of letters: A, B, D, G, K, L, M, N. It can feel like alphabet soup. But those letters are actually one of the more consumer-friendly parts of Medicare, once you know how they work.

Rapid City readers, here's what those Medigap letters actually mean

Here in Rapid City and across Pennington County, folks turning 65 often ask the same question: What does Medigap really do, and how do I compare one letter to another without getting lost? Let's walk through it plainly.

What Medigap is — and what it isn't

Medigap is private insurance that works alongside Original Medicare (Part A and Part B). It helps pay some of the out-of-pocket costs Original Medicare leaves behind — things like coinsurance, copayments, and some deductibles.

A few things Medigap is not:

• It is not Medicare Advantage. Medigap and Medicare Advantage are two different roads. You generally can't have both at the same time.
• It does not include prescription drug coverage. For that, you'd add a separate Part D plan.
• It does not cover long-term care, dental, vision, or hearing.

Medigap simply fills in gaps in Original Medicare. That's it — and that's why the plans are lettered rather than branded around extra perks.

Why the letters are standardized

Here's the part that trips people up. Medigap plans are standardized by the federal government. That means Plan G sold by one insurance company covers the exact same core benefits as Plan G sold by another company. Same with Plan N, Plan K, and the rest.

According to Medicare.gov, in most states there are up to 10 standardized Medigap plans, each labeled with a letter. Massachusetts, Minnesota, and Wisconsin standardize things a little differently, but South Dakota follows the common federal lettering.

So when you're comparing Plan G from Company 1 to Plan G from Company 2, the benefits are identical. What can differ is the price, the customer service, and how the company handles rate increases over time.

Also worth knowing: Plans C and F are no longer available to people who became newly eligible for Medicare on or after January 1, 2020. If you were eligible before that date, you may still be able to get them.

How to read a Medigap benefits chart without a headache

Medicare.gov publishes a standardized comparison chart. When you look at it, focus on a few key rows:

• Part A hospital coinsurance — covered by every Medigap plan.
• Part B coinsurance or copayment — covered fully by some letters, partly by others (Plan N, for example, uses small copays).
• Part A deductible — covered by most letters, but not all.
• Part B deductible — only covered by the older Plans C and F, and only if you were eligible before 2020.
• Foreign travel emergency — included in several letters, up to plan limits.

Plans K and L work a bit differently. They cost less up front but ask you to pay a percentage of certain costs until you hit an annual out-of-pocket limit, after which the plan pays 100% for the rest of the year.

Timing matters more than most people realize

The single biggest mistake we see in the Rapid City area isn't picking the "wrong" letter — it's missing the Medigap Open Enrollment Period.

That window is a one-time, six-month period that starts the month you're 65 and enrolled in Part B. During that window, you have a guaranteed issue right — insurers can't deny you coverage or charge you more because of your health history.

Miss that window, and outside of a few special situations, insurers in most states (including South Dakota) can use medical underwriting. That means they can look at your health and decide whether to offer you a policy and at what price.

This is separate from Medicare's Annual Enrollment Period (Oct. 15 – Dec. 7) and the Medicare Advantage Open Enrollment Period (Jan. 1 – March 31), which apply to different types of coverage.

A quick word on 2027 costs you'll hear about

Medigap doesn't cover prescription drugs, but many people pair it with a stand-alone Part D plan. For 2027, a few program-level figures are worth knowing:

• The Part D out-of-pocket cap is $2,100 in 2026 and $2,400 in 2027.
• The Part D maximum deductible is $615 in 2026 and $700 in 2027.
• The old "donut hole" coverage gap is gone as of 2025 — Part D now has three phases.
• The Medicare Prescription Payment Plan lets you spread drug costs across the year in monthly installments if you choose.
• IRMAA — the income-related surcharge on Part B and Part D — starts above $109,000 in income for a single filer in 2026.

These figures apply nationwide, not just in Pennington County.