Medicare Supplement

Which Medigap Letters Can Oxnard Shoppers Buy Today?

Oxnard sits in Ventura County, where people on Original Medicare can add a Medicare Supplement Insurance policy — better known as Medigap — to help with the out-of-pocket costs Medicare itself does not pay. Medigap is federally standardized, which means a Plan G sold by one company covers the same core benefits as a Plan G sold by another. What changes is the price, the customer service, and — in California — a few state rules worth knowing before you sign anything.

Medicare SupplementOxnard, CA

What Medigap is (and what it isn't)

Medigap is a private insurance policy that sits on top of Original Medicare. After Medicare pays its share of a covered service, your Medigap plan picks up some or all of what's left — things like the Part A hospital deductible, coinsurance, or the 20% Part B coinsurance, depending on which letter you buy.

Two things it is not: it is not Medicare Advantage (Part C), and it does not include prescription drug coverage. If you want drug coverage, you generally add a stand-alone Part D plan. You cannot have both Medigap and a Medicare Advantage plan at the same time.

The plan letters available in California

Medigap plans are labeled with letters. Federal law standardizes what each letter covers, so the benefits inside "Plan G," for example, are the same no matter which company sells it. (Massachusetts, Minnesota and Wisconsin standardize differently, but California follows the federal letters.)

For people newly eligible for Medicare today, these letters are on the market: A, B, D, G, G-HD, K, L, M and N. Plans C and F are closed to anyone who became eligible on or after January 1, 2020, because those letters covered the Part B deductible and federal law no longer allows new plans to do that. If you were eligible before that date, you may still be able to buy C or F.

"HD" stands for high-deductible. A high-deductible plan (like G-HD) has lower monthly premiums but you pay more out of pocket before it kicks in. Plans K and L pay a percentage of certain costs rather than the full amount, and they include a yearly out-of-pocket limit.

Which companies sell Medigap in Oxnard

Because Medigap is regulated at the state level, the list of companies selling policies to California residents is the same across Oxnard, Ventura and the rest of Ventura County. The table below lists every insurer with Medigap policies available in California and the letters each one offers.

The lineup includes national names like AARP - UnitedHealthcare Insurance Company, Anthem BlueCross - California, Blue Shield of California Life & Health Insurance Company, Humana (Humana Insurance Company), Mutual of Omaha (United World Life Insurance Company) and State Farm Mutual Automobile Insurance Company, along with several others. Not every company sells every letter, so if you have your eye on a specific letter, filter the table by that letter first.

Since the benefits inside a given letter are identical by law, comparing companies really comes down to premium, how the company handles rate changes over time, and its customer service reputation.

How Medigap pairs with Part D in 2026

Medigap does not cover prescriptions, so most people who choose Medigap also enroll in a stand-alone Part D drug plan. A few numbers to keep in mind for 2026:

• The Part D out-of-pocket cap is $2,100. Once your drug spending reaches that limit, you pay $0 for covered drugs for the rest of the year.
• The Part D maximum deductible is $615.
• The old coverage gap — the "donut hole" — has been eliminated since 2025. Part D now has three phases instead of four.
• The Medicare Prescription Payment Plan lets you spread your yearly drug costs across monthly payments instead of paying large amounts at the pharmacy counter.
• IRMAA — the income-related surcharge on Part B and Part D — begins above $109,000 in income for a single filer in 2026.

California rules that shape the choice

Federal law guarantees you can buy any Medigap policy sold in your state, with no medical underwriting, during your six-month Medigap Open Enrollment Period. That window starts the month you're 65 or older and enrolled in Part B. Miss it, and in most states an insurer can review your health and decide whether to sell you a policy or at what price.

California adds an important extra protection often called the "birthday rule." Each year around your birthday, current Medigap enrollees have a set window to switch to another Medigap policy with equal or lesser benefits, generally without new medical underwriting. The exact length of the window and the rules around it are set by the state — the California Department of Insurance and your local State Health Insurance Assistance Program (SHIP), called HICAP in California, can walk you through how it applies to your situation.

California also has additional guaranteed-issue rights in certain situations beyond what federal law requires. Because these rules change from time to time, it's worth confirming the current details with the state before you shop.

What to do next

If you're weighing Medigap in Oxnard, the practical steps are:

1. Confirm you're in (or heading into) Original Medicare, since Medigap only works with Parts A and B. 2. Pick a letter based on how much predictable, upfront cost you want vs. lower monthly premiums. 3. Compare companies that sell that letter — remembering the benefits inside the letter are identical. 4. If you want drug coverage, add a stand-alone Part D plan.

The Annual Enrollment Period (October 15 – December 7) and the Medicare Advantage Open Enrollment Period (January 1 – March 31) mostly affect Advantage and Part D choices, not Medigap. You can apply for Medigap at other times of the year, but outside your protected windows, medical underwriting may apply.