Massachusetts Medigap: Core & Supplement 1A Explained (2026)

Massachusetts is one of just three states that ignore the federal Medigap lettering, so you will not find a Medicare Supplement Plan G here. Instead, Massachusetts sells its own non-standardized plans: a Core plan, a Supplement 1A plan, and the older Supplement 1 plan that is now closed to anyone who became eligible for Medicare in 2020 or later. On top of that, no Massachusetts insurer may ever turn you down or price your policy based on your age or health, and premiums are community rated rather than climbing as you get older. This guide explains the Massachusetts plans, the protections that make this one of the most consumer-friendly Medigap markets in the country, and the two limits worth knowing before you wait: year-round enrollment is offered at each insurer's option, and enrolling late can carry a surcharge.1

How Medigap works in Massachusetts

A Medigap policy is private insurance that pays the deductibles and coinsurance Original Medicare leaves to you. Medigap in Massachusetts (Medicare Supplement Insurance) works only alongside Original Medicare, not with a Medicare Advantage plan, and each policy covers one person. A married couple who both want coverage need two policies.2

Most of the country uses the federal standardized framework, where Medigap is sold as lettered plans (A through D, F, G, and K through N) and every policy with the same letter offers the same basic benefits, whichever insurer sells it.2 Massachusetts is one of three "waiver states," along with Minnesota and Wisconsin, that received federal permission to standardize their own way instead. That means the lettered plans you read about in national Medigap guides do not exist here. The practical upshot is that you choose among a short menu of Massachusetts plan types rather than picking a single letter.1

The gaps Medigap closes are real. After the Part B deductible ($283 in 2026), Original Medicare still leaves you a 20% coinsurance on the approved amount for most outpatient care, and it sets no yearly limit on what you pay out of pocket unless you have supplemental coverage such as Medigap. Part A adds a hospital deductible of $1,736 per benefit period in 2026, and that deductible can apply more than once in a year. A Massachusetts Medigap plan is that supplemental coverage.3

The Massachusetts plans: Core, Supplement 1A, and Supplement 1

Massachusetts offers a small set of plans rather than the federal A-through-N menu. Two are open to people newly eligible for Medicare, and one is closed.

The Core plan is the basic option. It covers a baseline set of gaps in Original Medicare but leaves more cost-sharing with you than the Supplement plans do. It is the lower-premium choice for someone who wants a floor of protection rather than the most complete coverage.

Supplement 1A is the more complete plan available to people newly eligible for Medicare. It is the closest available equivalent to the older Supplement 1, with one difference that matters at the pharmacy counter and the doctor's office: it does not cover the annual Part B deductible, so you pay that yourself each year. Ask any insurer you are considering for its current Massachusetts benefit summary before you buy. The state sets what each plan type covers, so the comparison you want is on price and service.

Supplement 1 also covered the Part B deductible, which made it the most complete plan on the market. It is now closed to anyone who became eligible for Medicare in 2020 or later, for the same federal reason the lettered Plans C and F closed elsewhere.1

Why Supplement 1 is closed if you became eligible for Medicare in 2020 or later

Supplement 1 once covered the annual Part B deductible on top of the other gaps, which made it the most complete Massachusetts plan. Under the Medicare Access and CHIP Reauthorization Act of 2015 (MACRA), federal law now closes any Medigap plan that pays the Part B deductible to people who are new to Medicare on or after January 1, 2020. You count as new only if both parts are true: you turned 65 on or after January 1, 2020, and you didn't already have Medicare Part A (through a disability or End-Stage Renal Disease, for example) before that date.2 In the lettered states, that same rule closed Plans C and F; in Massachusetts, it closed Supplement 1.4

The closure works by eligibility date, not purchase date. If you became eligible for Medicare before January 1, 2020 but have not yet enrolled, you can still buy Supplement 1 in Massachusetts, and if you already have it you can keep it.1 The federal ban also doesn't reach someone who had Medicare Part A through a disability or ESRD before 2020 and is only now turning 65.4 If you became eligible on or after that date, Supplement 1 is off the table, which is why Supplement 1A has become the top-tier choice for newer enrollees: it is identical to Supplement 1 except that you pay the one Part B deductible yourself.1

How the plans compare

Because benefits inside each Massachusetts plan type are set by the state, a Core plan from one insurer covers exactly what a Core plan from another covers. The plan type settles what you get, so the price is what you compare.1

Massachusetts guaranteed issue, the February-March window, and enrolling late

This is where Massachusetts stands apart. The federal Medigap Open Enrollment Period is a one-time six-month window that starts the first month you are both 65 or older and enrolled in Part B. During it, an insurer can't refuse to sell you a policy it offers, can't use medical underwriting, and can't charge you more for health problems, though it may still make you wait up to six months for coverage of a pre-existing condition unless you had at least six months of continuous prior creditable coverage.5 Massachusetts gives you far more.

Under the Division of Insurance's regulation 211 CMR 71, a Massachusetts insurer may never deny a Medigap policy, condition its issuance, or price it because of your age, health status, claims experience, care you have received, medical condition, or genetic information, and it may not require a genetic test. That protection has no window; it applies at any time. The state also runs a required annual guaranteed-issue open enrollment from February 1 to March 31, with coverage effective June 1, or earlier if that is when your Medicare coverage first takes effect. Massachusetts also prohibits pre-existing condition waiting periods, so coverage starts without a health-based delay.1

Two limits are worth knowing before you decide to wait. First, year-round enrollment is offered at each insurer's option, not guaranteed statewide. The regulation lets issuers "elect to maintain continuous open enrollment," so ask the specific carrier you want whether it accepts applications outside the required windows. Second, enrolling late can cost you: an insurer may apply a surcharge of up to 15% a year, for up to three years, to a late enrollee. You are one if you apply after the six-month period that begins when you first enroll in Part B, lose employer-sponsored coverage, or become a Massachusetts resident. You are not one if you had reasonably actuarially equivalent prior coverage, without a break, for the lesser of three years or the time since you first became eligible, running to within 30 days of the new policy's start.1

The practical value is large. Because your health can never be used to deny you a Massachusetts policy or set its price, you can move to a different plan or carrier during the February-March window, or at any time with an insurer that keeps continuous open enrollment. One cost to check before you switch: moving to coverage with a higher benefit level that is not reasonably actuarially equivalent to your current policy counts as upgrading, and an insurer may add a surcharge for that too, under the same 15%-a-year, three-year cap. Even so, shopping on price stays a real, ongoing option rather than a one-time event.1

How Medigap is priced in Massachusetts

Because Massachusetts bars insurers from pricing a Medigap policy on age or health, premiums are community rated: they do not vary by age or health status, and your rate does not climb simply because you get older. This is different from the issue-age and attained-age pricing common in lettered states, where a low first-year quote can rise over time. Community rating does not mean every buyer pays an identical price, though: a premium can carry the late-enrollment or upgrade surcharge described above, up to 15% a year for up to three years.1

Premiums still vary. Medicare.gov says a Medigap premium depends on which policy you buy, where you live, and other factors, and the amount can change each year.3 Because the benefits inside each plan type are identical, get quotes for the same plan type from more than one insurer before you choose. Note that Medigap does not include prescription drug coverage, so you add a separate Part D plan for that.

Who regulates Medigap in Massachusetts

Massachusetts Medigap plans are overseen by the state Division of Insurance, and the 2026 Massachusetts Consumer Guide to Medicare from the Commonwealth lays out the current plans and rules. If you have a complaint or a question about a specific policy or insurer, the state's consumer resources are the place to start. SHINE (Serving the Health Insurance Needs of Everyone) (official page) counselors offer free counseling and help you explore your Medicare plan options.6 You can reach the SHINE Program at 1-800-243-4636.6

Learn More

Find personalized help comparing Medicare Supplement plans in Massachusetts at brevy.com.

The information on Brevy.com is for educational purposes only and is not a substitute for professional legal, financial, or medical advice. Rules vary by state and program and change frequently. Always verify with the relevant agency or a qualified professional. Brevy is not a law firm, financial advisor, or healthcare provider.