Every Medicare Supplement policy sold in the United States must contain a core set of provisions required by Section 1882 of the Social Security Act.1Social Security Administration. Social Security Act 1882 – Certification of Medicare Supplemental Health Insurance Policies Those mandatory provisions include standardized benefit packages, guaranteed renewability, strict limits on pre-existing condition waiting periods, a 30-day free look period, minimum loss ratios, guaranteed issue rights in specific situations, the ability to suspend coverage during Medicaid eligibility, and a flat ban on selling duplicate coverage. States can add protections on top of this federal floor, but no insurer and no state can take any of it away.
Standardized Benefit Packages
The most visible mandatory provision is standardization. Every Medigap policy must conform to one of ten benefit packages identified by the letters A, B, C, D, F, G, K, L, M, and N.2Medicare. Compare Medigap Plan Benefits A Plan G from one carrier covers exactly the same benefits as a Plan G from any other. The only differences between carriers selling the same letter plan are price, service, and financial strength.
Plan A is the most basic package, covering Part A coinsurance and hospital costs for up to an additional 365 days after Medicare benefits run out. Higher-letter plans layer on benefits such as the Part A deductible, skilled nursing facility coinsurance, Part B excess charges, and foreign travel emergency care. Plans K and L work differently, paying a percentage of certain costs (50% for K, 75% for L) until you hit an annual out-of-pocket limit, after which the plan pays 100%.
Two boundaries matter here. Plans C and F are no longer available to anyone who became eligible for Medicare on or after January 1, 2020, because they were the only plans that covered the Part B deductible and Congress closed them to new enrollees. And standardization applies to benefits, not price: the ten letter packages are federally fixed, but federal law does not standardize what carriers charge or how they rate premiums by age.
Guaranteed Renewability
Every Medigap policy must be guaranteed renewable. The insurer cannot cancel or refuse to renew your policy because your health has changed or because you have filed claims.1Social Security Administration. Social Security Act 1882 – Certification of Medicare Supplemental Health Insurance Policies As long as premiums are paid, coverage continues.
An insurer can drop a Medigap policy only in a handful of narrow situations: nonpayment of premium, material misrepresentation on the original application, or the insurance company itself going out of business.3Medicare. Learn How Medigap Works Anything outside those grounds is a regulatory violation. Premium increases are permitted, but they must apply across an entire rating class rather than targeting an individual policyholder.
Open Enrollment and Guaranteed Issue Rights
Federal law gives you a one-time, six-month Medigap open enrollment period. It begins the first month you are both 65 or older and enrolled in Medicare Part B. During that window, no insurer can refuse to sell you any Medigap policy it offers, charge more because of health conditions, or use medical underwriting on your application.4Medicare. Get Ready to Buy This window does not repeat annually. Miss it, and in most states insurers can underwrite you from that point forward.
Outside open enrollment, federal law still protects you in specific situations through guaranteed issue rights. When a qualifying event occurs, insurers must sell you a Medigap policy without underwriting, without health-based pricing, and without pre-existing condition waiting periods. Qualifying events include:
- Your Medigap insurer goes bankrupt or your coverage ends through no fault of your own.
- You leave a Medicare Advantage Plan and return to Original Medicare, particularly if you joined Medicare Advantage within your first year of eligibility.
- Your employer group coverage ends, leaving you with Original Medicare and no supplement.
- Your insurer or plan broke the rules or misled you about your coverage.
In most guaranteed issue situations you have 63 days from the end of your prior coverage to apply. The set of plans available under a guaranteed issue right may be narrower than during open enrollment, often limited to Plans A, B, C, D, F, G, K, or L, but the core protection holds: no underwriting, no health-based premium.5Medicare. When Can I Buy a Medigap Policy
Limits on Pre-existing Condition Waiting Periods
Federal law tightly limits how insurers treat pre-existing conditions. For Medigap purposes, a pre-existing condition is one for which you received medical advice or treatment in the six months before your policy’s effective date. If an insurer imposes a waiting period for services related to that condition, the waiting period cannot exceed six months from the policy’s effective date.
That cap shrinks based on your prior coverage. For every month of continuous “creditable coverage” before you bought the Medigap policy, the insurer must cut the waiting period by one month. Creditable coverage includes employer group plans, individual policies, Medicare Advantage, Medicaid, and prior Medigap coverage. Four months of prior coverage, for example, leaves at most a two-month wait.
If you buy during your six-month open enrollment period, the insurer cannot impose any pre-existing condition waiting period at all.4Medicare. Get Ready to Buy The same is true when you apply under a guaranteed issue right. Enrolling on time wipes the waiting period out entirely.
The 30-Day Free Look Period
Every Medigap policy must include a free look period of at least 30 days from the day you receive the policy.1Social Security Administration. Social Security Act 1882 – Certification of Medicare Supplemental Health Insurance Policies You can return the policy for any reason during that window and receive a full refund of every premium paid.6Medicare. Can I Change My Medigap Policy No explanation is required.
If you are replacing an existing Medigap policy, keep the old one in force until you have decided to stay with the new one. Canceling the prior policy before the free look window closes leaves you with no fallback if the new policy turns out to be a poor fit.
Prohibition on Duplicate Coverage
Federal law makes it illegal for anyone to knowingly sell you a health insurance policy that duplicates benefits you already have through Medicare or an existing Medigap policy.1Social Security Administration. Social Security Act 1882 – Certification of Medicare Supplemental Health Insurance Policies You cannot hold two Medigap policies at the same time, and an agent who sells you a second policy knowing you already have one is breaking the law. Civil enforcement runs through the Department of Health and Human Services; criminal cases run through the Department of Justice.
The same rule means a Medigap policy cannot be sold to someone enrolled in a Medicare Advantage Plan, since Medicare Advantage replaces Original Medicare’s coverage structure. If you are moving from Medicare Advantage back to Original Medicare, your new Medigap policy should not start until the Advantage plan coverage actually ends.
Minimum Loss Ratio
Medigap insurers must return a minimum share of collected premiums to policyholders as benefits. The federal floor is 75% for group policies and 65% for individual policies.1Social Security Administration. Social Security Act 1882 – Certification of Medicare Supplemental Health Insurance Policies An insurer that falls below those thresholds must issue proportional refunds or credit the difference against future premiums.
Those minimums are lower than the Affordable Care Act’s standards for most other health insurance, which range from 80% to 85%. Competitive pressure often keeps carriers above the Medigap floor, but the legal minimum is useful to know when comparing prices between carriers offering the same letter plan.
Suspension During Medicaid Eligibility
If you become eligible for Medicaid after already holding a Medigap policy, federal law lets you suspend the Medigap coverage for up to 24 months rather than canceling it. You must request the suspension within 90 days of your Medicaid eligibility determination.7Centers for Medicare & Medicaid Services. Program Memorandum – Medigap Policy Suspension During Medicaid Eligibility
If you lose Medicaid eligibility within those 24 months, your insurer must reinstate the Medigap policy on the same terms and premium classification you had before the suspension. No new waiting periods, no underwriting, and no penalty for the gap, provided you request reinstatement within 90 days of losing Medicaid. The provision keeps people from being permanently locked out of Medigap just because they temporarily qualified for Medicaid.
What Federal Law Does Not Standardize: Pricing
Benefit packages are federally fixed, but pricing is not. Every Medigap insurer uses one of three rating methods, and the choice is left to the carrier and state law:
- Community-rated policies charge everyone the same premium regardless of age, though premiums can still rise with inflation.
- Issue-age-rated policies base your premium on your age when you bought the policy; aging alone does not raise your rate afterward.
- Attained-age-rated policies raise premiums as you grow older. These often start cheapest and become the most expensive over time.8Medicare. Choosing a Medigap Policy
Ask any carrier which method it uses before comparing monthly rates. A plan that looks like a bargain at 65 under attained-age rating can cost significantly more by 75 than a community-rated plan that seemed expensive at the start.