Medicare Supplement plans, commonly called Medigap, are regulated on two levels. The federal government, through the Centers for Medicare & Medicaid Services, sets minimum benefit standards under Section 1882 of the Social Security Act. State insurance departments handle the day-to-day work: licensing insurers, approving policy forms, reviewing premium increases, and responding to consumer complaints. Your rights depend on both layers, and in some areas on which state you live in.
What CMS and Federal Law Control
CMS administers the federal framework for Medigap under 42 U.S.C. ยง 1395ss. The statute requires every state to run a regulatory program at least as strict as the standards developed by the National Association of Insurance Commissioners, and it authorizes CMS to step in when a state falls short.1Office of the Law Revision Counsel. 42 US Code 1395ss – Certification of Medicare Supplemental Health Insurance Policies Federal rules set the floor. States build on top of it.
Standardized Benefit Packages
The most visible federal rule is standardization. Every Medigap policy carries a letter designation, and every policy with the same letter offers identical benefits no matter which company sells it. The currently available plans are A, B, C, D, F, G, K, L, M, and N.2Medicare. Compare Medigap Plan Benefits Two Plan G policies from different insurers differ only in price.
Plans C and F are closed to anyone who became eligible for Medicare on or after January 1, 2020. Both covered the Part B deductible, and Congress ended that option for new beneficiaries. If you were eligible before that date but didn’t enroll, you may still be able to buy them.2Medicare. Compare Medigap Plan Benefits
Three states run their own standardization systems instead of using the letters. Massachusetts offers a Core Plan and two Supplement tiers. Minnesota uses a Basic Plan and an Extended Basic Plan with optional riders. Wisconsin sells one Basic Plan with optional riders.3National Association of Insurance Commissioners (NAIC). Choosing a Medigap Policy The federal protections still apply in those states; the packaging just looks different.
Open Enrollment and Guaranteed Issue
Federal law gives you a single six-month Medigap open enrollment period. It starts the first month you are both 65 or older and enrolled in Medicare Part B. During that window, any insurer selling Medigap in your state must sell you any policy it offers, cannot charge you more because of your health history, and cannot deny you coverage.4Medicare. Get Medigap Basics It’s a one-time window that does not repeat.
Outside that window, federal law still creates guaranteed issue rights in a few situations where you lose coverage through no fault of your own. Common triggers include your Medicare Advantage plan leaving your service area, your employer group plan ending, or your Medigap insurer going out of business. There is also a Medicare Advantage trial right: if you join a Medicare Advantage plan for the first time and want to leave, you can return to Original Medicare and buy any Medigap policy within 12 months of joining, with full guaranteed issue protection.5Medicare. Trial Right to Buy Medigap
Guaranteed Renewability
Once you have a policy, federal law protects you from losing it. Your insurer must renew each year as long as you pay your premium. An insurer can drop you only if you stop paying, if you were dishonest on your application, or if the company goes out of business.6Medicare. Learn How Medigap Works Developing a health condition or filing many claims is not grounds for cancellation. This applies in every state.
Loss Ratio Requirements
Federal rules also control how much of your premium goes to paying claims. Medigap insurers must meet minimum loss ratios: 65 percent for individual policies and 75 percent for group policies.7eCFR. 42 CFR Part 403 Subpart B – Medicare Supplemental Policies Insurers report their actual ratios, and regulators can require refunds or block rate increases when a company consistently falls below the threshold.
What State Insurance Departments Control
State insurance departments do most of the hands-on regulatory work. Each one licenses the companies allowed to sell Medigap in the state, reviews and approves policy forms, and has authority over premium changes. Section 1395ss explicitly requires each state’s program to include a process for approving or disapproving proposed premium increases, and some states hold public hearings before allowing one.1Office of the Law Revision Counsel. 42 US Code 1395ss – Certification of Medicare Supplemental Health Insurance Policies Because approval standards vary widely, real consumer protection often depends on which state regulator is watching.
State agencies also take complaints, run market examinations, and bring enforcement actions when insurers violate state law. If you have a billing dispute or believe a claim was wrongly denied, your state insurance department is the first place to go.
Premium Rating Methods
States decide which methods insurers can use to price policies. There are three:
- Community-rated policies charge everyone the same base premium regardless of age. Premiums can still rise with inflation, but not because you got older. This is the most protective method for long-term costs.
- Issue-age-rated policies base your premium on how old you were when you bought the policy. A 65-year-old pays less than a 72-year-old buying the same plan for the first time, but neither faces age-based increases after purchase.
- Attained-age-rated policies rise as you age. They often start cheapest and can become the most expensive over time.
Eight states require community rating for policyholders 65 and older, effectively banning age-based premium increases: Arkansas, Connecticut, Maine, Massachusetts, Minnesota, New York, Vermont, and Washington. In every other state, attained-age rating is allowed and is the most common method.
Access for People Under 65
Federal law does not require Medigap insurers to sell to Medicare beneficiaries younger than 65 who qualify through disability or end-stage renal disease.8Medicare. When Can I Buy a Medigap Policy Roughly 35 states require insurers to make at least one type of Medigap policy available to under-65 beneficiaries, though which policies must be offered and at what price varies widely.
The NAIC’s Role
The National Association of Insurance Commissioners is an organization of state insurance commissioners from all 50 states, the District of Columbia, and U.S. territories. It has no direct enforcement authority over any insurer. Its role is to develop model laws and regulations that states can choose to adopt.9National Association of Insurance Commissioners (NAIC). Model Laws NAIC Model Regulation 651 sets out the minimum benefit standards, disclosure rules, and loss ratio requirements for Medigap. When Congress updated Medigap standardization in 2010, the NAIC revised its model to match, and states adopted the update into their own codes. Most states follow the NAIC models closely, which is why Medigap rules feel broadly similar across the country even though enforcement is state by state.
Where to Take a Problem
Two resources handle most Medigap questions and disputes. Your state insurance department takes regulatory complaints, tells you whether an insurer is licensed in your state, and can investigate claims-handling issues. For plan comparisons and enrollment questions, State Health Insurance Assistance Programs offer free one-on-one counseling from trained volunteers.10State Health Insurance Assistance Programs. What We Do SHIP counselors are trained specifically on Medicare, Medigap, Medicare Advantage, and Part D.11Administration for Community Living (ACL). State Health Insurance Assistance Program (SHIP)