Medicare Supplement

Medigap in Illinois for 2026: the rules Chicago shoppers should know

Chicago — As Medicare's fall enrollment season runs through Dec. 7 and 2026 plan pricing settles in, Illinois residents who buy or shop Medicare Supplement Insurance — better known as Medigap — should know that a few things are shifting for the new year. The plan letters themselves are the same, but the numbers plugged into them (like the Part B deductible that Plans G and N are built around) reset every January, and insurers refile their rates with the state on their own schedules. Here is what Chicago readers should watch for.

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What's actually changing for 2026

The Medigap plan letters — A, B, D, G, G-HD, K, L, M, and N for anyone newly eligible today — are not changing. What changes each January are the Medicare cost figures that some of these plans are designed around. Plan G, for example, pays almost everything Original Medicare leaves behind except the annual Part B deductible, and that deductible resets every year. Plan N works the same way, plus small copays for some office and ER visits.

CMS publishes the new Part B deductible amount each fall. Once it's official, that new number is what Plan G and Plan N enrollees will pay out of pocket before those plans kick in for Part B services in 2026.

Plans C and F: still closed to newly eligible

This rule isn't new, but it still trips people up. If you became eligible for Medicare on or after Jan. 1, 2020, you cannot buy Plan C or Plan F — the two plans that used to cover the Part B deductible. People who were already eligible before that date can keep those plans or, in some cases, still buy them.

For everyone else, Plan G is the closest equivalent, and the high-deductible version of Plan G (G-HD) offers similar coverage after a higher yearly out-of-pocket amount.

Rate-adjustment season in Illinois

Medigap premiums are not set by Medicare. Each insurer files rates with the Illinois Department of Insurance, and those filings are reviewed at the state level. Rate changes can take effect at different times of year depending on the carrier, so two neighbors on the same plan letter can see increases in different months.

Because Illinois is not one of the handful of states with a "birthday rule" or annual guaranteed right to switch Medigap plans, moving to a cheaper policy after your initial 6-month Medigap Open Enrollment window usually means going through medical underwriting. That doesn't mean you can't switch — it means an insurer can ask health questions and decide whether to accept you.

If your renewal notice for 2026 shows a higher premium, it's worth calling around to see what other insurers would charge for the same plan letter before you decide.

How to see which insurers sell Medigap in Chicago

Chicago is in Cook County, and Medigap availability in Illinois is set at the state level rather than the county level — but premiums for the same plan can vary by ZIP code. Three tools will give you the current list:

• Medicare.gov's Medigap policy search. Enter your ZIP code and it will show every insurer selling each plan letter in your area, with sample premiums.
• The Illinois Department of Insurance Medigap rate comparison guide. The state publishes a guide that lists licensed Medigap insurers and their rates by age and ZIP.
• Illinois SHIP (Senior Health Insurance Program). Free, unbiased counseling from trained volunteers who can walk you through your options one on one.

If an insurer stops offering a Medigap plan in Illinois, current policyholders are generally allowed to keep their coverage; the plan is simply closed to new applicants.

What to do before Dec. 7 (and after)

Dec. 7 is the deadline for Medicare Advantage and Part D changes — not for Medigap. Medigap can be shopped at any time of year. That said, fall is a natural moment to review the whole picture:

• If you have a Medigap policy plus a stand-alone Part D drug plan, use Medicare Plan Finder during Oct. 15–Dec. 7 to check that your Part D plan still fits your prescriptions for 2026.
• If you're thinking about moving from Medicare Advantage back to Original Medicare plus Medigap, know that once you leave your initial Medigap Open Enrollment window, most Illinois insurers can underwrite.
• Note the 2026 Part D figures that affect drug costs regardless of your Medigap plan: a $2,100 out-of-pocket cap, a maximum $615 deductible, and the optional Medicare Prescription Payment Plan that lets you spread drug costs across the year.