Missouri's Medigap anniversary rule, explained

If you live in Missouri and already have a Medicare Supplement (Medigap) policy, you can usually switch to the same plan letter with a different insurance company each year, without answering health questions, in a window around your policy's anniversary date. That window is commonly described as the 30 days before and the 30 days after the anniversary.

By Nick Heyse, independent licensed insurance agent (NPN 20605586) · Last reviewed October 2026

How it works

• It's tied to your policy, not your birthday. The anniversary is the date your current Medigap policy started each year.
• Same plan letter only. You can move from one company's Plan G to another company's Plan G, for example — not from Plan N to Plan G.
• Why people use it: premiums for the same plan letter can differ between companies, and rates change over time. The coverage for a given letter is standardized, so comparing is mostly about price and the company.

What it doesn't do

• It doesn't let you move from Medicare Advantage to a Medigap policy without health questions. Separate federal "guaranteed issue" rules cover some of those cases.
• It doesn't replace your one-time six-month Medigap Open Enrollment Period when you first get Part B.

Kansas is different

Kansas has no comparable rule. If you live on the Kansas side of the metro, read Medigap in Kansas instead.