Medicare Supplement

Modesto on Original Medicare? How Medigap Fits In

Modesto sits in Stanislaus County, where residents on Original Medicare can add a Medicare Supplement Insurance policy — better known as Medigap — to help pay some of the out-of-pocket costs Medicare Parts A and B leave behind. In California, Medigap plans follow the federal standardized letter system, which means a Plan G sold by one company covers the same benefits as a Plan G sold by another. What can differ is the price, the customer service, and how each insurer prices policies over time.

Medicare SupplementModesto, CA

Here is a plain-English guide to the letters you can buy today, how Medigap fits with Original Medicare and Part D, and the California rules worth knowing before you shop.

What Medigap is — and isn't

Medigap is private insurance that pays some of what Original Medicare doesn't. Depending on the letter, it can help with your Part A hospital deductible, Part B coinsurance, skilled nursing coinsurance, and other gaps.

Medigap is not the same as a Medicare Advantage plan. You cannot have both. Medigap only works with Original Medicare (Parts A and B). It also doesn't include prescription drug coverage, so most people who choose Medigap also sign up for a separate Part D plan.

The plan letters you can buy in California

California follows the federal standardized letter system. If you became eligible for Medicare on or after January 1, 2020, you can choose from Plans A, B, D, G, G-HD, K, L, M and N. Plans C and F remain available only to people who were eligible for Medicare before that date.

Each letter is a fixed benefits package set by federal rules. That means a Plan N is a Plan N — the coverage is the same at every insurer that sells it. What changes from company to company is the premium and how it's calculated.

The high-deductible versions (G-HD, and F-HD for those still eligible) work like regular Plan G or F, but you pay a set yearly deductible first before the plan starts covering costs.

Insurers selling Medigap in California

Several companies offer Medigap in California, and not all of them sell every letter. In alphabetical order, the insurers include AARP - UnitedHealthcare Insurance Company, AFLAC, American Retirement Life Insurance Company (CIGNA), Anthem BlueCross - California, Bankers Life (Underwritten by Washington National Insurance Company), Blue Shield of California Life & Health Insurance Company, Continental Life Insurance Company of Brentwood, Tennessee (Aetna), Everence Association Inc., Humana (Humana Insurance Company), Insurance Company of North America, Lumos Insurance, Mutual of Omaha (United World Life Insurance Company), State Farm Mutual Automobile Insurance Company, United American Insurance Company, and USAA Life Insurance Company.

The table below lists every insurer along with the plan letters each one sells in the state. Because benefits within a letter are identical, comparison shopping across companies usually comes down to price and service.

How Medigap pairs with Part D

Medigap doesn't cover prescriptions. If you want drug coverage, you'll typically add a standalone Medicare Part D plan.

A few 2026 Part D figures are worth knowing as you plan:

• The Part D out-of-pocket cap is $2,100 for 2026. Once your covered drug spending hits that limit, 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 as of 2025, so Part D now has three phases instead of four.
• The Medicare Prescription Payment Plan is an optional program that lets you spread your drug costs across the calendar year in monthly payments instead of paying all at once at the pharmacy counter.

If your income is above $109,000 as a single filer in 2026, an IRMAA surcharge may apply to your Part B and Part D premiums.

California rules that shape your choice

California has consumer protections that go beyond federal law. The most well known is the "birthday rule," which gives Medigap policyholders a yearly window around their birthday to switch to another Medigap plan with equal or lesser benefits — generally without new medical underwriting. There are specific timing and eligibility details that matter, so check them before you act.

Federally, you also get a one-time Medigap Open Enrollment Period that begins the month your Part B starts (if you're 65 or older). During that window, insurers can't turn you down or charge more based on your health. Outside that window, and outside California's special protections, insurers can generally use medical underwriting.

For the current details on birthday-rule timing, guaranteed-issue rights, and other California-specific protections, the California Department of Insurance and your local State Health Insurance Assistance Program (SHIP) — called HICAP in California — are the authoritative sources.

A few tips before you shop

• Confirm which plan letter fits your budget and how you use care. A lower-premium letter with more cost-sharing may work fine for some; others prefer more predictable coverage.
• Ask each insurer how it prices its policies (community-rated, issue-age-rated, or attained-age-rated) and how rates have changed historically.
• Remember that identical letters offer identical benefits — so your comparison is really about price, service and long-term rate stability.
• If you take prescriptions, review Part D plans separately each fall during the Annual Enrollment Period (October 15 – December 7).