Medicare Supplement

Turning 65 in St. Louis? How Medigap rules apply

ST. LOUIS — As 2026 approaches, Medicare Supplement (Medigap) shoppers in St. Louis are looking at a familiar set of moving parts: which standardized plan letters they can buy, how the Part B deductible reset flows through Plans G and N, and when insurers file their new rates with the state. None of the standardized letters are going away this year, but the details around them are worth a fresh look before you sign anything.

What is (and isn’t) changing with plan letters

The standardized Medigap plan letters are set by federal law, and for 2026 they look the same as this year. If you are newly eligible for Medicare, you can shop Plans A, B, D, G, high-deductible G, K, L, M and N. Plans C and F — the two that once paid the Part B deductible for you — are still closed to anyone who became eligible for Medicare on or after January 1, 2020. If you were eligible before that date, you can still buy or keep them.

That “eligibility cutoff” trips people up every year in St. Louis, which is in the City of St. Louis and borders St. Louis County. A spouse who turned 65 in 2019 may have options a spouse turning 65 in 2026 does not. It is worth confirming your own eligibility date before you compare letters.

The Part B deductible reset and why Plans G and N care

Plan G and Plan N are the two letters most new enrollees compare, and both are designed around the Part B deductible. With Plan G, you pay that deductible yourself each calendar year, and the plan picks up Part B coinsurance after that. Plan N works similarly, with some office-visit and emergency-room copays layered on top.

Every January 1, the Part B deductible resets — meaning the meter starts at zero again, and Medicare publishes the new dollar amount for the year. Because we can’t quote the 2026 figure here, the cleanest place to see it is medicare.gov once CMS posts it. If you already have Plan G or N, nothing about your coverage changes at the reset; you simply meet the new-year deductible the first time you use Part B services.

High-deductible Plan G (G-HD) follows the same reset logic but with a much larger yearly deductible set by CMS before the plan starts paying. It’s the same trade-off as always: lower premium, more out-of-pocket exposure up front.

Rate-adjustment season in Missouri

Medigap premiums are not set by Medicare. In Missouri, each insurer files its rates with the Missouri Department of Commerce and Insurance, and those filings drive the renewal notices that land in mailboxes each year. Rates can change based on your age (in some pricing methods), medical inflation, and the insurer’s own claims experience.

A few practical points for St. Louis readers:

• Your renewal letter is the single most important document. It tells you your new premium and effective date.
• If your premium jumped, that does not automatically mean a different insurer will be cheaper — but it is a reasonable time to shop.
• Outside your six-month Medigap Open Enrollment Period (which starts when you’re 65 and enrolled in Part B), insurers in Missouri can generally use medical underwriting. That means switching isn’t always guaranteed.
• Missouri has an “anniversary” rule that lets many Medigap policyholders switch to the same lettered plan with another insurer around their policy anniversary. Your local SHIP counselor (CLAIM in Missouri) can walk you through whether it applies to you.

For current rate guides and filings, the Missouri Department of Commerce and Insurance is the official source.

Who sells Medigap in Missouri

Availability of Medigap in Missouri remains wide. The table below lists every insurer and the specific plan letters each one offers, from AARP – UnitedHealthcare Insurance Company through Wisconsin Physicians Service Insurance Corporation. Familiar names include Aetna Health and Life Insurance Company, AFLAC, Blue Cross and Blue Shield of Kansas City, Humana (Humana Insurance Company), Mutual of Omaha (United World Life Insurance Company), State Farm Mutual Automobile Insurance Company and USAA Life Insurance Company, among others.

Two reminders when you read the table:

• Every insurer selling the same lettered plan must cover the same standardized benefits. A Plan G is a Plan G. What differs is price, customer service, and how each company handles rate increases over time.
• Not every insurer sells every letter. If you have your heart set on Plan D or Plan M, for example, your choices are narrower than for Plan G or N.

How this fits with the rest of Medicare in 2026

Medigap is separate from Part D drug coverage, but many St. Louis readers make both decisions in the same season. For 2026, Part D has a $2,100 out-of-pocket cap, a maximum deductible of $615, and the old “donut hole” is gone — replaced by a three-phase design that started in 2025. There’s also the Medicare Prescription Payment Plan, which lets you spread drug costs across the year in monthly amounts. IRMAA surcharges (which can affect Part B and Part D premiums) begin above $109,000 in income for a single filer in 2026.

Medicare Advantage and Part D changes happen during the Annual Enrollment Period, October 15 – December 7, with a separate Medicare Advantage Open Enrollment Period from January 1 – March 31. Medigap, by contrast, has no single national enrollment window — you apply when you’re eligible, and after that, rules like underwriting and Missouri’s anniversary provision come into play.