3.2 Missouri Medicare Supplement (Medigap) Regulations

Medigap Open Enrollment Period

A Medicare Supplement (Medigap) policy fills gaps in Original Medicare (deductibles, coinsurance, copays). Missouri follows the federal 6-month open enrollment period (OEP), which begins on the first day of the month in which the beneficiary is BOTH:

• Age 65 or older, AND
• Enrolled in Medicare Part B.

During this one-time 6-month window the applicant has full guaranteed issue rights:

• The insurer must accept the application regardless of health.
• No pre-existing condition waiting period may be imposed if the applicant had 6 months of prior creditable coverage; otherwise a limited look-back applies but is reduced by creditable coverage.
• The applicant cannot be charged more for health conditions and may choose any Medigap plan (A-N) the carrier offers.

Exam trap: The OEP is tied to Part B enrollment at age 65, not to Part A and not to the calendar year. Someone who delays Part B (because they still have employer coverage) does not start the clock until Part B begins.

Missouri's Anniversary Rule (State-Specific)

This is the single most-tested Missouri Medigap fact. Beyond the federal OEP, Missouri uniquely grants an annual guaranteed-issue right known as the anniversary rule. Each year a Medigap policyholder may switch to the same lettered plan (for example, one Plan G to a different carrier's Plan G) on a guaranteed-issue basis during a window that opens 30 days before the policy anniversary and continues 30 days after it—a roughly 60-day window.

Worked example: A Missouri beneficiary bought Plan G effective May 1. From April 1 (30 days before) through May 31 (30 days after) of each year, she may move that Plan G to any other Missouri carrier offering Plan G with no medical questions—often to capture a lower premium.

Other Guaranteed Issue Triggering Events

Outside the OEP and anniversary rule, federal guaranteed-issue protections still apply within 63 days of certain losses:

Standardized Plans A Through N

Missouri requires Medigap policies to follow the federal standardized plan letters. Each letter offers identical core benefits across all carriers, so only price and service differ.

Why C and F closed: The MACRA law barred Medigap plans from covering the Part B deductible for anyone first eligible for Medicare on or after January 1, 2020. C and F both pay that deductible, so new enrollees gravitate to Plan G instead.

Rate Regulation and Pre-Existing Conditions

Missouri permits three rating methods, and the producer must disclose which one applies:

• Attained-age: premium rises as the insured ages (cheapest early, costliest later).
• Issue-age: premium locked to age at purchase; does not rise with age.
• Community-rated: same premium regardless of age.

All rate increases must be filed with DCI. Insurers may not use health status to set rates during a guaranteed-issue period.

A beneficiary moving from a prior plan with at least 6 months of creditable coverage generally faces no waiting period.

Medicare Basics the Exam Assumes

To answer Medigap questions you must know what Medigap supplements. Original Medicare has two parts:

• Part A (hospital): has a per-benefit-period deductible and daily coinsurance after day 60. Medigap can cover these gaps.
• Part B (medical): has an annual deductible plus 20% coinsurance with no out-of-pocket cap. Medigap covers the 20% coinsurance; only pre-2020-eligible plans (C, F) cover the Part B deductible.

Excess charges arise when a provider does not accept Medicare assignment and bills up to 15% above the approved amount; only Plans F and G cover Part B excess charges. Medigap does not include prescription drug coverage—that is Part D, sold separately. A producer who tells a client a Medigap policy includes drug coverage has made a material misrepresentation.

Marketing and Suitability Standards

Missouri enforces NAIC Medigap marketing rules to protect seniors:

Producers must deliver the official "Choosing a Medigap Policy" guide and an outline of coverage, and complete a suitability review so the senior is not sold an unsuitable or duplicate plan.