Medicare Supplement

Turning 65 in Fontana? How Medigap letters line up

Fontana sits in San Bernardino County, where residents on Original Medicare have a familiar choice to weigh: whether to add a Medicare Supplement Insurance policy, better known as Medigap. These policies help pay some of the out-of-pocket costs Original Medicare leaves behind, and in California — like most of the country — they come in standardized "letter" plans. That standardization is the single most useful thing to understand before you shop.

What Medigap actually does

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

A few ground rules worth remembering:

• Medigap only works with Original Medicare. If you're enrolled in a Medicare Advantage plan, you cannot use a Medigap policy at the same time.
• Medigap does not include prescription drug coverage. Most people pair it with a stand-alone Part D plan.
• Each policy covers one person. Spouses need their own policies.

The letters you can buy in California today

California follows the federal standardization used in most states (Massachusetts, Minnesota and Wisconsin do it differently). If you're newly eligible for Medicare now, the plan letters available to you are: A, B, D, G, G-HD, K, L, M and N.

Plans C and F are still on the market, but only for people who were eligible for Medicare before January 1, 2020. That change came from federal law, not California, and it applies nationwide.

Because the benefits inside each letter are set by federal rules, a Plan N sold by one insurer covers the same things as a Plan N sold by another. What can differ between carriers is the price, how they set that price (issue-age, attained-age or community-rated), customer service, and household or other discounts they may offer.

How Medigap and Part D fit together

Medigap and Part D are two separate products. If you go the Original Medicare + Medigap route and you want help paying for prescriptions, you'll typically enroll in a stand-alone Part D plan.

A few 2026 Part D facts worth knowing while you shop:

• The annual out-of-pocket cap on covered drugs is $2,100 in 2026.
• The Part D maximum deductible is $615.
• The old coverage gap (the "donut hole") was eliminated in 2025; the benefit now has three phases.
• The Medicare Prescription Payment Plan lets you spread your drug costs across the calendar year in monthly installments if you choose.
• IRMAA income-related surcharges on Part B and Part D begin above $109,000 in income for a single filer in 2026.

California rules that shape your choice

Two state-level points come up often for Fontana readers:

The California "birthday rule." Once you have a Medigap policy, California generally lets you switch to another Medigap plan with equal or lesser benefits — from any insurer — during a window tied to your birthday each year, without new medical underwriting. The exact length of that window and how it's applied is set by state law and can change; confirm the current rules with the California Department of Insurance or your local State Health Insurance Assistance Program (SHIP), known here as HICAP.

Your Medigap Open Enrollment Period. Federally, you have a one-time six-month window that starts the month your Part B coverage begins (and you're 65 or older). During that window, insurers must sell you any Medigap plan they offer at their best available rate, regardless of your health history. Outside that window — and outside limited guaranteed-issue situations — insurers in California can use medical underwriting to decide whether to sell you a policy and at what price.

Who sells Medigap in California

The table below lists every insurer currently selling Medigap in California and the letter plans each one offers. It includes names you may recognize — AARP - UnitedHealthcare Insurance Company, Anthem BlueCross - California, Blue Shield of California Life & Health Insurance Company, Humana, Mutual of Omaha and State Farm among them — along with several others such as AFLAC, American Retirement Life Insurance Company (CIGNA), Bankers Life, Continental Life Insurance Company of Brentwood, Tennessee (Aetna), Everence Association Inc., Insurance Company of North America, Lumos Insurance, United American Insurance Company and USAA Life Insurance Company.

Not every carrier sells every letter. When you compare, it helps to pick the letter first (based on the benefits you want), then compare the insurers that offer that letter side by side.

A simple way to shop

1. Decide whether Original Medicare + Medigap + Part D is the path you want, versus a Medicare Advantage plan. You can't combine the two. 2. Pick the plan letter whose benefits fit how you use care. 3. Compare insurers that sell that letter, focusing on price, how they set price, and their track record for rate stability. 4. If you take prescriptions, choose a Part D plan that covers your drugs at pharmacies you use. 5. Watch the calendar. The Annual Enrollment Period runs October 15 – December 7 for Part D and Medicare Advantage changes. The Medicare Advantage Open Enrollment Period runs January 1 – March 31. Medigap has its own timing rules, including the six-month Open Enrollment window described above and California's birthday rule.

Where to get unbiased help

• Medicare.gov has a Medigap policy search that shows every plan and insurer available by ZIP code.
• 1-800-MEDICARE (1-800-633-4227) is staffed 24/7.
• California's SHIP is called HICAP (Health Insurance Counseling and Advocacy Program) and offers free, one-on-one counseling.
• The California Department of Insurance publishes Medigap rate guides and can answer questions about state-specific consumer rights.