Medicare Supplement

Medicare Supplement Basics for Berkeley Residents

BERKELEY, Calif. — If you've been reading up on Medicare, you've probably run into the word "Medigap." It's another name for Medicare Supplement insurance, and it's one of the more misunderstood pieces of the program. Here in Berkeley, where many people age into Medicare while still working part-time at the university or a local business, the question comes up often: does Medigap actually help, and what do those letters — Plan G, Plan N, Plan K — really mean?

Here's a plain-language walk-through.

What Medigap is designed to do

Original Medicare (Part A for hospital care and Part B for doctor visits) pays a big share of your covered medical costs — but not all of them. You're still responsible for things like the Part A hospital deductible, the 20% coinsurance under Part B, and other cost-sharing that has no yearly cap on its own.

A Medigap policy is private insurance you buy from an insurance company to help pay some of those leftover costs. That's it. It doesn't replace Medicare; it works with it. You keep using your red, white and blue Medicare card, and your Medigap policy picks up its share behind the scenes.

How the standardized letters work

This is the part that trips people up. In most states, including California, Medigap plans are sold using standardized letters: A, B, C, D, F, G, K, L, M and N. (Plans C and F are only available to people who became eligible for Medicare before January 1, 2020.)

The important thing to understand: the letter defines the benefits. A Plan G sold by Company X covers the exact same core benefits as a Plan G sold by Company Y. What can differ between companies is the monthly premium, customer service, and how the price changes over time. So when you compare Medigap options, you're really comparing price and company reputation for the same benefit package.

Plan G and Plan N are two of the most common choices for people newly eligible today. Plans K and L work more like traditional insurance with cost-sharing and a yearly out-of-pocket limit. You can see the full benefit grid on Medicare.gov.

What Medigap does not cover

Medigap is narrower than a lot of people expect. It generally does not cover:

• Prescription drugs (you'd add a separate Part D plan)
• Routine dental, vision or hearing care
• Long-term care, such as ongoing nursing home stays
• Private-duty nursing

If you want drug coverage, you enroll in a stand-alone Part D plan. In 2026, Part D has a maximum deductible of $615 and a new $2,100 annual out-of-pocket cap on covered drugs. The old "donut hole" coverage gap is gone as of 2025 — Part D now has three phases instead of four. If your drug costs are uneven month to month, you can also ask about the Medicare Prescription Payment Plan, which spreads what you owe across the year.

Medigap vs. Medicare Advantage — an either/or choice

This is worth saying clearly: you cannot have both a Medigap policy and a Medicare Advantage plan at the same time. They're two different paths.

• Original Medicare + Medigap + (usually) a Part D plan. You see any provider that accepts Medicare, and your Medigap fills in cost-sharing.
• Medicare Advantage (Part C). A private plan replaces how you get Parts A and B, usually with a network, and often bundles in drug coverage and extras.

Berkeley is in Alameda County, where a large number of Medicare Advantage plans are offered each year. That gives residents plenty of options on the Advantage side — but it's a separate decision from the Medigap question. Plan availability and counts are set at the county level, not the city level, so a neighbor in Oakland or Fremont sees the same menu you do.

When you can buy Medigap matters

The best window to buy a Medigap policy is your Medigap Open Enrollment Period — the six months that start the month you're 65 and enrolled in Part B. During that window, insurance companies can't turn you down or charge you more because of your health.

Outside that window, in most cases, insurers in California can look at your health history and decide whether to offer you a policy and at what price. California also has a "birthday rule" that gives current Medigap enrollees an annual chance to switch to an equal or lesser plan without medical underwriting. If you're already in a Medigap plan, that's worth knowing about.

Note that the fall Annual Enrollment Period (October 15 – December 7) and the Medicare Advantage Open Enrollment Period (January 1 – March 31) apply to Advantage and Part D plans — not to Medigap. Medigap has its own timing rules.

How to decide if Medigap fits you

There's no universally right answer. A few honest questions to ask yourself:

• Do you value predictable out-of-pocket costs, even if that means a higher monthly premium?
• Do you want the freedom to see any provider in the country who accepts Medicare, without network rules?
• Do you travel often, or split time between Berkeley and somewhere else?
• Are you comfortable managing a separate Part D plan for prescriptions?

If you answered yes to most of those, Medigap is worth a closer look. If you'd rather have a bundled plan with extras and are fine with a network, Medicare Advantage might be a better match. Your income also matters — IRMAA surcharges on Part B and Part D begin above $109,000 for a single filer in 2026, and that's the same whether you choose Medigap or Advantage.