Medicare Supplement

Medicare Supplement basics for Fairfield: what Medigap pays

FAIRFIELD, Calif. — If you've ever tried to sort out Medicare on your own, you know the alphabet soup can be dizzying. Parts A, B, C, D — and then a whole second set of letters for Medigap plans. Here's the short version: Medicare Supplement insurance, better known as Medigap, is designed to help pay some of the out-of-pocket costs that Original Medicare leaves behind. And unlike most insurance, the plans are standardized by letter, which makes comparing them easier once you know what to look for.

Medicare Supplement insurance, explained: what Medigap does and doesn't cover

Fairfield is in Solano County, where residents on Original Medicare can shop Medigap plans sold by private insurers. The benefits inside each lettered plan are set by federal rules, so a Plan G from one company covers the same core benefits as a Plan G from another. What can differ is the price and the customer service.

What Medigap actually does

Medigap works alongside Original Medicare (Part A and Part B). After Medicare pays its share of a covered service, your Medigap policy picks up some or all of the leftover costs — things like coinsurance, copayments, and, in some plans, the Part A hospital deductible.

Medigap does not:

• Replace Medicare. You still need Part A and Part B.
• Include prescription drug coverage. For drugs, you'd add a stand-alone Part D plan.
• Work with Medicare Advantage. You can't use a Medigap policy to pay Advantage plan costs, and it's illegal for someone to sell you one if you're on Advantage.
• Cover long-term care, dental, vision, or hearing aids in most cases.

How the standardized letters work

There are 10 standardized Medigap plans available in most states, labeled A, B, C, D, F, G, K, L, M, and N. (Massachusetts, Minnesota, and Wisconsin standardize theirs differently.) Each letter represents a fixed set of benefits.

A few things worth knowing:

• Plans C and F are no longer sold to people who became eligible for Medicare on or after January 1, 2020. If you were eligible before that date, you may still be able to buy them.
• Plan G has become a popular choice for newly eligible enrollees because it covers nearly everything Plan F does, except the Part B deductible.
• Plans K and L have lower premiums but include yearly out-of-pocket limits and cost-sharing.
• Plan N typically has lower premiums than Plan G but may involve small copays for some office and ER visits.

Because the benefits inside each letter are identical from company to company, your comparison really comes down to premium, the insurer's track record, and how they handle rate increases over time.

The best time to buy — and why timing matters

The single most important thing to understand about Medigap is the Medigap Open Enrollment Period. It's a one-time, six-month window that starts the month you're 65 or older and enrolled in Part B. During this window, insurers must sell you any Medigap policy they offer at their best available rate, regardless of your health history.

Miss that window, and in most states — including California — insurers can use medical underwriting. That means they can charge you more, or turn you down entirely, based on your health. California does offer a "birthday rule" that gives existing Medigap policyholders an annual window to switch to an equal or lesser plan without underwriting, but the initial six-month window is still the cleanest way in.

Medigap vs. Medicare Advantage — a common mix-up

Medigap and Medicare Advantage (Part C) are two different roads. You pick one or the other; you can't use both at the same time.

• Medigap pairs with Original Medicare and helps pay your share of costs. You keep the flexibility to see any provider nationwide who accepts Medicare.
• Medicare Advantage replaces Original Medicare with a private plan that bundles hospital, medical, and often drug coverage, usually inside a network.

Neither is automatically better. It depends on how you use care, whether you travel, your preferred doctors, and your budget.

What about drug coverage in 2026?

Medigap doesn't cover prescriptions, so most people pair it with a stand-alone Part D plan. A few 2026 figures worth remembering:

• The Part D out-of-pocket cap is $2,100 for 2026. Once you hit it, you pay nothing more for covered drugs the rest of the year.
• The maximum Part D deductible is $615.
• The old "donut hole" coverage gap was eliminated in 2025 — Part D now has three phases.
• The Medicare Prescription Payment Plan lets you spread your drug costs into monthly payments instead of paying at the pharmacy counter.
• IRMAA surcharges — higher Part B and Part D premiums for higher earners — begin above $109,000 in income for a single filer in 2026.