Medicare Supplement

Medigap in Boston: why Massachusetts uses Core, Supplement 1 and 1A instead of letters

If you live in Boston and are shopping for a Medicare Supplement policy, you may notice something confusing right away: the plan letters you keep reading about online — Plan G, Plan N, Plan F — are not what Massachusetts sells. Instead, the state has its own three standardized Medigap plans, and every insurer that offers Medigap here has to build their policies around them.

That difference matters, because most national Medigap guides describe the federal letter plans. If you are comparing coverage in Suffolk County, you are really comparing three named plans, sold by different insurers, at different prices.

Why Boston shoppers see three plans, not ten

Massachusetts is one of three states — along with Minnesota and Wisconsin — that standardize Medigap differently from the federal system. In Boston, the plans available are:

• Core
• Supplement 1
• Supplement 1A

Core is the most basic package. Supplement 1 is a broader plan, but under federal rules it is closed to people who first became eligible for Medicare on or after January 1, 2020, because it covers the Part B deductible. Supplement 1A was created for people newly eligible on or after that date and covers similar benefits without paying that deductible for you.

Which of these you can buy depends in part on when you became eligible for Medicare. The Medicare.gov Medigap policy search will show you what you qualify for when you enter your ZIP code and date of birth.

How Medigap fits with Original Medicare and Part D

A Medigap plan is designed to sit on top of Original Medicare. It helps pay some of the out-of-pocket costs — like coinsurance and hospital costs — that Parts A and B leave behind.

A few ground rules to keep in mind:

• You must be enrolled in Part A and Part B to buy a Medigap policy.
• Medigap does not work with Medicare Advantage. You choose one path or the other.
• Medigap does not include prescription drug coverage. If you want drug coverage, you add a stand-alone Part D plan.

For 2026, Part D has an out-of-pocket cap of $2,100 and a maximum deductible of $615. The old "donut hole" coverage gap was eliminated in 2025, so Part D now has three phases instead of four. If paying drug costs in big chunks is hard on your budget, the Medicare Prescription Payment Plan lets you spread those costs across the calendar year in monthly installments.

Higher-income enrollees may pay an IRMAA surcharge on Part B and Part D; for 2026, that starts above $109,000 for a single filer.

The Massachusetts rules that shape your choice

State rules matter a lot here, because they affect when you can buy and what you will pay.

Your strongest protection is the federal Medigap Open Enrollment Period: a six-month window that starts the month you are 65 or older and enrolled in Part B. During that window, insurers must sell you any Medigap plan they offer at their standard rate, no health questions asked.

Massachusetts also offers rights beyond the federal minimum in some situations, including a continuous or annual open enrollment for Medigap that other states do not have. Because those state-specific rules can change and depend on your situation, confirm the details with the Massachusetts Division of Insurance or SHINE (Serving the Health Insurance Needs of Everyone) before you switch.

How to compare plans and prices in Boston

Because benefits inside each named plan (Core, Supplement 1, Supplement 1A) are standardized, the same plan name gives you the same core coverage no matter who sells it. What differs between insurers is:

• The monthly premium
• How the insurer calculates rate increases over time
• Customer service, billing options and extras

Ask each company how they price their policies. Some use community rating (everyone in the state pays the same), some use issue-age rating (based on your age when you bought), and some use attained-age rating (which rises as you get older). The pricing method affects what happens to your premium down the road, not just today.

Three good places to gather names and rates for Suffolk County:

• The Medigap policy search on medicare.gov, sorted by your ZIP code
• The Medigap rate guide published by the Massachusetts Division of Insurance
• SHINE counselors, who can walk through your options at no cost

Key dates to keep on your calendar

Medigap itself does not have a national annual enrollment window — you can apply any time, though outside guaranteed-issue periods insurers can use medical underwriting. Two other dates still matter:

• October 15 – December 7: Medicare's Annual Enrollment Period, when you can add, drop or change a Part D drug plan.
• January 1 – March 31: Medicare Advantage Open Enrollment, useful if you are on Advantage now and thinking of switching to Original Medicare plus a Medigap policy.