3.2 South Dakota Medicare Supplement Regulations

The 6-Month Open Enrollment Period

A Medicare Supplement policy ("Medigap") pays the gaps in Original Medicare — deductibles, coinsurance, and copays. South Dakota adopts the federal NAIC Medicare Supplement Insurance Minimum Standards Model, so the rules track national law with state enforcement by the Division of Insurance.

The single most-tested fact is the 6-month Medigap Open Enrollment Period (OEP). It begins on the first day of the month in which the applicant is both age 65 or older AND enrolled in Medicare Part B. During these six months the carrier must:

This window is once-per-lifetime and does not reset. A person who delays Part B because of active employer coverage gets the OEP later, when Part B starts. Outside the OEP, the insurer may require a medical exam, decline the applicant, or impose up to a 6-month pre-existing condition waiting period — unless a guaranteed-issue event applies.

Guaranteed-Issue ("Trial Right") Situations

Federal law grants guaranteed-issue rights outside the OEP in specific circumstances, including:

• A Medicare Advantage plan leaves the service area or the carrier goes bankrupt.
• The beneficiary moves out of the plan's service area.
• A Medicare Advantage trial right: someone who joined an MA plan at 65 and disenrolls within 12 months may return to Medigap.
• An employer group retiree plan ends.

In these cases the applicant generally must apply within 63 days of losing the prior coverage. The exam loves to pair the 6-month OEP with the 63-day guaranteed-issue window — keep them distinct.

How Medigap Fits With the Rest of Medicare

To answer Medigap questions correctly you must place the policy within Original Medicare. Part A covers inpatient hospital care (subject to a deductible per benefit period and coinsurance after day 60); Part B covers physician and outpatient services (annual deductible plus 20% coinsurance with no out-of-pocket cap). Medigap exists precisely to pay those gaps. By contrast, Part C (Medicare Advantage) replaces Original Medicare through a private plan, and Part D covers prescription drugs separately — modern Medigap plans do not include drug coverage, so a beneficiary needs a standalone Part D plan.

A producer who tells a client a Plan G covers prescriptions is giving false information and risks an unfair-trade-practice violation.

Standardized Plan Letters

Medigap benefits are federally standardized, so a Plan G from any insurer covers the identical benefits — only premium and service differ. This standardization is the core consumer protection: it lets buyers compare on price and company stability, not benefit fine print.

Closed plans: Plans C and F cover the Part B deductible, so they are no longer sold to anyone who became eligible for Medicare on or after January 1, 2020. People eligible before that date may keep or still buy them. High-deductible F and G exist as variants.

Marketing, Replacement, and Prohibited Practices

South Dakota and federal rules tightly control how Medigap is sold to seniors:

• 30-day free look: the buyer may return the policy within 30 days for a full premium refund.
• Replacement notice: replacing an existing Medigap or health policy requires a signed Notice to Applicant Regarding Replacement; the producer must compare benefits and avoid churning.
• No duplicate coverage: it is illegal to knowingly sell a Medigap policy that duplicates coverage the applicant already has, or to sell Medigap to someone enrolled in Medicaid or a Medicare Advantage plan (Medigap does not work with MA).
• No high-pressure or misleading sales: cold-lead advertising, twisting, and fear tactics aimed at beneficiaries are prohibited unfair trade practices.

Worked Example

A man turns 65 on March 12 and enrolls in Part B effective March 1. His Medigap OEP runs March 1 through August 31. If he applies in July, the insurer must issue Plan G at the standard rate with no health questions. If he waits until the following January, the carrier may underwrite, decline, or impose a 6-month pre-existing waiting period.

Common Traps

• The OEP starts with Part B enrollment plus age 65 — not Part A, and not the Initial Enrollment Period.
• Plan F is closed to newly eligible beneficiaries; do not recommend it to a 2026 new enrollee.
• A Medigap policy cannot be sold to coordinate with a Medicare Advantage plan.