Medicare Supplement

Eligible for Medicare After 2020? Oakland Medigap Rules Shifted

Oakland, Calif. — If you have a Medigap policy in Oakland, or you're thinking about buying one, a handful of things quietly reset every year. The plan letters you're allowed to buy depend on when you first became eligible for Medicare. The Part B deductible — the number that Plans G and N are built around — is refreshed by CMS each year. And in California, insurers file their new Medigap rates with the state, so premiums can shift heading into 2027.

Here is a plain-language look at what is changing, what isn't, and where to check the numbers for your own ZIP code.

What Medigap is, in one paragraph

Medigap — also called Medicare Supplement Insurance — is a private policy that pays some of the out-of-pocket costs Original Medicare leaves behind, like coinsurance and copays. It only works alongside Original Medicare (Parts A and B), not with a Medicare Advantage plan. The letters (A, B, D, G, N and so on) are standardized by federal rule, which means a Plan G from one insurer covers the same core benefits as a Plan G from another. What differs is the premium and the company's service — not the benefits inside the letter.

The plan letters Oakland shoppers can actually buy

Oakland is in Alameda County, and California follows the federal Medigap standardization rules. If you're newly eligible for Medicare today, these are the letters available to you: A, B, D, G, G high-deductible (G-HD), K, L, M and N.

Plans C and F are still around, but only for people who became eligible for Medicare before Jan. 1, 2020. That cutoff isn't new, but it trips up a lot of readers who see an older neighbor with a Plan F and assume they can buy one too. If your Medicare eligibility date is 2020 or later, you cannot.

Plan G and Plan N are the two letters most new buyers end up comparing, because they carry the broadest cost-sharing coverage still open to newly eligible enrollees.

Why the Part B deductible reset matters for Plans G and N

Both Plan G and Plan N are designed to kick in after you meet the Part B deductible. CMS sets that deductible each calendar year. When it goes up, you pay a little more out of pocket before your Medigap starts filling in the gaps; when it holds steady, so does your math.

The 2027 Part B deductible will be announced by CMS in the fall. If you're on Plan G or N, that's the number to watch — it's the one dollar figure that changes what "first-dollar" looks like for you, even if your monthly premium is unchanged.

Plan G-HD (high-deductible G) works differently: you pay a separate, higher deductible before the plan pays. That threshold is also reset annually.

Rate-adjustment season in California

Medigap premiums are not set by the federal government. In California, insurers file proposed rate changes with the California Department of Insurance, and those filings become the new premiums you see at renewal. Rate season generally runs through the fall, with new rates taking effect on a rolling basis.

A few things are worth knowing:

• California is one of the states with extra Medigap consumer protections, including a "birthday rule" that lets you switch to an equal or lesser Medigap plan each year around your birthday without medical underwriting. If a rate hike lands on your renewal, that window is often the practical answer.
• Outside that window, switching Medigap plans in California can involve health questions. Your one guaranteed no-underwriting window is your six-month Medigap Open Enrollment Period when you first enroll in Part B at 65 or older.
• The California Department of Insurance publishes a Medigap rate comparison guide. It is the cleanest way to see what companies are charging in your ZIP code.

Insurers entering or leaving

We are not publishing an insurer list for California in this piece, because Medigap carrier participation shifts through the year and the authoritative source is the Medicare.gov Medigap policy search. Enter your Oakland ZIP code there and you'll see every company currently selling each plan letter in your area. If a carrier you already have exits, your existing policy generally isn't cancelled — but that's a call to make to your insurer and to HICAP, California's SHIP, before you assume anything.

A quick note on Part D and IRMAA for 2026

Medigap does not include prescription drug coverage, so most Medigap enrollees pair their policy with a standalone Part D plan. A few 2026 program facts worth keeping in view as you plan for 2027:

• Part D has a $2,100 out-of-pocket cap in 2026, and a maximum deductible of $615.
• The old coverage gap ("donut hole") is gone as of 2025 — Part D now has three phases.
• The Medicare Prescription Payment Plan lets you spread drug costs across the year in monthly installments.
• IRMAA income surcharges begin above $109,000 for a single filer in 2026.
• Annual Enrollment runs Oct. 15 – Dec. 7; Medicare Advantage Open Enrollment runs Jan. 1 – March 31. Medigap itself does not have an annual enrollment window — you can apply any time, but outside protected windows you may be underwritten.

How to check your own numbers

Three places, in this order:

1. Medicare.gov Medigap policy search — enter your Oakland ZIP to see every plan letter and every insurer currently selling in Alameda County. 2. California Department of Insurance Medigap rate guide — compare premiums company by company for the plan letter you're considering. 3. California SHIP (HICAP) — free, unbiased one-on-one counseling. Call 1-800-434-0222.

You can also call 1-800-MEDICARE (1-800-633-4227), 24/7.