3.2 DC Medicare Supplement (Medigap) Regulations

Medicare Supplement Basics

Medicare Supplement insurance (Medigap) is private coverage that pays the deductibles, coinsurance, and copayments that Original Medicare (Parts A and B) leaves to the beneficiary. It is sold only to people enrolled in Parts A and B and does not coordinate with a Medicare Advantage (Part C) plan — by federal law it is illegal to sell a Medigap policy to someone in a Medicare Advantage plan unless they are disenrolling.

DC follows the federal standardized plan framework administered through the NAIC model and CMS, so a Medigap product is identified by a letter, and the benefits behind each letter are identical across every carrier.

Because benefits are standardized, the only legitimate reasons to compare two carriers' identical-letter plans are price, financial strength, and service — a point the exam tests as a consumer-protection principle. Plans C and F (which pay the Part B deductible) are closed to anyone who became eligible for Medicare on or after January 1, 2020; an applicant who turned 65 in 2026 cannot buy a new Plan F.

The 6-Month Open Enrollment Window

The single most tested Medigap rule is the 6-month 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, and it runs for six months. During this one-time window the applicant has powerful rights:

• Guaranteed issue — the carrier must accept the applicant regardless of health.
• No health underwriting — the insurer cannot ask medical questions to decline coverage or surcharge.
• No pre-existing condition exclusion beyond a limited federal look-back (and that look-back is waived if the applicant had at least 6 months of prior creditable coverage).
• Standard (community-like) rating — the applicant pays the same rate a healthy person of the same age pays.

Worked example: a man enrolls in Part B effective the month he turns 65 in February 2026. His OEP runs February through July 2026. If he applies for Plan G in May, the carrier must issue it with no medical questions. If he waits until September, the OEP has closed and the insurer may medically underwrite and decline or rate him up.

Guaranteed-Issue Triggers After OEP

DC follows the federal list of guaranteed-issue (GI) situations that re-open guaranteed acceptance after the OEP ends:

No Birthday Rule; Required Disclosures

DC does NOT have a 'Birthday Rule.' States like California and Oregon let beneficiaries switch each year to a same-or-lesser plan during a window around their birthday without underwriting — DC offers no such ongoing switch right. Outside OEP and a GI trigger, a DC beneficiary who wants to change Medigap plans is subject to medical underwriting.

Producers must also follow strict marketing rules: deliver the 'Choosing a Medigap Policy' buyer's guide and an outline of coverage at or before application, complete a replacement notice when replacing existing Medigap, and never sell duplicate Medicare coverage. High-pressure tactics, misrepresenting standardized benefits, and "twisting" a beneficiary out of suitable coverage are prohibited unfair practices. When two answer choices look plausible, choose the one that gives the beneficiary clearer disclosure and avoids replacing coverage without informed consent.

Medigap vs. Medicare Advantage on the Exam

Candidates lose points by blurring Medigap with Medicare Advantage (Part C). Medigap supplements Original Medicare by paying its cost-sharing and lets the beneficiary see any provider who accepts Medicare nationwide; it charges a monthly premium on top of the Part B premium and carries no networks. Medicare Advantage replaces the way Original Medicare is delivered, bundling Parts A and B (often with Part D drug coverage) through a private plan with provider networks and an annual out-of-pocket maximum, frequently at a low or $0 premium.

A beneficiary cannot meaningfully use both at once, and it is illegal to sell Medigap to someone who intends to stay in Medicare Advantage.

Premium Rating Methods

Medigap premiums in DC may be filed under three rating structures, and the exam tests how each ages:

Attained-age plans often look cheapest at 65 but climb steeply later, so a thorough producer discloses the long-run cost path rather than just the entry premium — again the consumer-protection theme DISB enforces. All three methods may still rise with general inflation and medical trend.