13.2 Medicare Supplement (Medigap) Policies

Medicare Supplement insurance — commonly called Medigap — is private coverage that pays the deductibles, coinsurance, and copayments left by Original Medicare (Parts A and B). It does not work with Medicare Advantage; a person cannot legally hold both a Medigap policy and a Part C plan at the same time. Medigap pays after Medicare and only for services Medicare approves; it does not add new benefit categories such as dental or long-term custodial care.

Standardization

In most states Medigap plans are standardized into lettered plans (A, B, C, D, F, G, K, L, M, N). Within a letter, benefits are identical across all insurers, so companies compete on price and service, not coverage. Massachusetts, Minnesota, and Wisconsin standardize differently.

Exam Trap: Plans C and F (which cover the Part B deductible) are NOT available to people who became eligible for Medicare on or after January 1, 2020. Plan G is the closest substitute for new enrollees.

Open Enrollment and Guaranteed Issue

The Medigap Open Enrollment Period is a one-time, 6-month window that begins the first month a person is both age 65 or older AND enrolled in Part B. During this window the insurer must use guaranteed issue: it cannot deny coverage, charge more, or impose extended waiting periods based on health.

A pre-existing condition is generally one treated or diagnosed within 6 months before the policy effective date; the look-back/exclusion cannot exceed 6 months and is reduced by prior creditable coverage.

Required Consumer Protections

• Free-look period: at least 30 days to return the policy for a full refund.
• Guaranteed renewable: the insurer cannot cancel for health changes, only for nonpayment or material misrepresentation.
• Replacement rules: producers must avoid unnecessary replacement; selling a second Medigap to someone who already has one (or has Medicaid) is generally prohibited.
• Outline of Coverage: must be delivered at or before application.

Key Point: Outside the 6-month open enrollment window — and absent a guaranteed-issue event such as losing employer coverage — insurers may medically underwrite a Medigap applicant and decline coverage.

Reading the Standardized Plan Grid

The exam expects you to reason about the lettered plans rather than memorize every cell. The logic is simple: every plan must cover the core benefits — the Part A coinsurance and hospital costs up to an additional 365 days after Medicare benefits are exhausted, the Part B coinsurance or copayment, the first three pints of blood, and Part A hospice cost-sharing. Plans then layer on extras such as the Part A deductible, skilled-nursing-facility coinsurance, and foreign travel emergency coverage.

Plans F and G are the most comprehensive; the only meaningful difference between them is that F pays the Part B deductible and G does not, which is exactly why F was closed to anyone first eligible for Medicare on or after January 1, 2020 (it would have covered every dollar of Part B cost-sharing, which the law no longer permits for new enrollees).

Plans K and L are cost-sharing designs: they pay a fixed percentage (75 percent and 50 percent of certain costs, respectively) until the beneficiary reaches an annual out-of-pocket limit, after which the plan pays 100 percent. Plan N keeps premiums low by charging a copay of up to twenty dollars for some office visits and up to fifty dollars for an emergency-room visit that does not result in admission. Understanding this "trade lower premium for some cost-sharing" pattern lets you answer plan-recommendation questions without a chart.

Underwriting, Switching, and Suitability

The single most tested Medigap concept is the six-month open enrollment period and how it differs from a guaranteed-issue event. During open enrollment the insurer must issue any plan it sells regardless of health. Outside that window, the applicant generally faces medical underwriting and can be declined or rated — unless a federal guaranteed-issue right applies, such as losing employer coverage, a Medicare Advantage plan leaving the service area, or the trial-right scenario where a beneficiary who first joined Medicare Advantage at 65 switches back to Original Medicare within twelve months.

For producers, suitability rules prohibit selling a beneficiary a second Medigap policy when an in-force policy already provides the coverage, and they forbid selling Medigap to someone on Medicaid (whose cost-sharing Medicaid already covers). The required replacement notice, the 30-day free look, and the guaranteed-renewable nature of the contract are all consumer protections you should be able to state precisely, because Oregon adopts the NAIC Medigap model and tests these figures directly.