Medicare Supplement

Medigap in California for 2027: 15 Insurers and the Plans They Sell

SACRAMENTO — Californians who want help paying the out-of-pocket costs that Original Medicare leaves behind have a familiar tool: a Medicare Supplement policy, better known as Medigap. For 2027, Medicare.gov's Medigap policy search lists 15 insurers for ZIP code 90001, selling a mix of federally standardized plans. Here is what the lineup looks like and how the enrollment rules work.

What is Medigap and how is it different from Medicare Advantage in California?

Medigap is private insurance that works alongside Original Medicare (Part A and Part B) to pay some of the deductibles, coinsurance and copays that Medicare does not. It is not Medicare Advantage. A person with Medigap keeps Original Medicare as their primary coverage and can see any doctor or hospital in the country that accepts Medicare; the Medigap plan pays its share of the Medicare-approved costs.

Medicare Advantage, by contrast, replaces Original Medicare with a private plan that typically uses a network and often bundles in drug coverage. A beneficiary enrolls in either a Medicare Advantage plan or Original Medicare plus (optionally) a Medigap and a Part D plan — not both at once.

Which insurers sell Medigap in California for 2027, and which plan letters do they offer?

For ZIP code 90001, Medicare.gov's Medigap policy search lists 15 insurers. What is actually sold can differ by ZIP code and by age, sex and tobacco use, and premiums and underwriting rules vary. In alphabetical order, the insurers and the plan letters shown for them are:

• AARP – UnitedHealthcare Insurance Company: A, B, C, F, G, K, L, N
• AFLAC: A, F, G, N
• American Retirement Life Insurance Company (CIGNA): A, F, G, G-HD, N
• Anthem BlueCross – California: A, F, G, N
• Bankers Life (Underwritten by Washington National Insurance Company): A, F, G, G-HD, N
• Blue Shield of California Life & Health Insurance Company: A, F, G, N
• Continental Life Insurance Company of Brentwood, Tennessee (Aetna): A, B, F, F-HD, G, N
• Everence Association Inc.: A, F, G, N
• Humana (Humana Insurance Company): A, B, C, F, F-HD, G, G-HD, K, L, N
• Insurance Company of North America: A, F, G, G-HD, N
• Lumos Insurance: A, F, G, N
• Mutual of Omaha (United World Life Insurance Company): A, F, G, G-HD, N
• State Farm Mutual Automobile Insurance Company: A, C, D, F, G, N
• United American Insurance Company: A, B, C, D, F, F-HD, G, G-HD, K, L, N
• USAA Life Insurance Company: A, F, G, N

Across the listed insurers, the plan letters sold by at least one carrier are A, B, C, D, F, F-HD, G, G-HD, K and L, and N. Plans C and F are closed to people who first became eligible for Medicare on or after January 1, 2020.

When is the six-month Medigap Open Enrollment Period in California, and why does it matter?

A person's Medigap Open Enrollment Period is the six months that begin the first month they are both 65 or older and enrolled in Medicare Part B. During that one-time window, any Medigap policy sold to California residents must be issued without medical underwriting — the insurer cannot deny coverage or charge more because of health history.

Outside that window, in most situations California residents can still apply for a Medigap policy, but insurers may use medical underwriting unless a guaranteed-issue right applies. That is why the six-month window is the single most important Medigap date on the calendar.

What happens to Californians whose Medicare Advantage plan is not returning in 2027?

According to CMS Landscape files, about 74 Medicare Advantage plans offered somewhere in California in 2026 will not be offered anywhere in the state in 2027. Members of a plan that is not returning get a federal guaranteed-issue right to buy certain Medigap plans — meaning insurers must sell them specific lettered plans without health underwriting, within the time limits set by federal rules.

Affected members receive a non-renewal notice from their plan. Medicare.gov explains which plan letters qualify for the guaranteed-issue right and the deadlines for applying.

Does Medigap cover prescription drugs in California, or is a Part D plan needed separately?

Medigap does not cover prescription drugs. A Californian who wants drug coverage with Original Medicare and Medigap enrolls in a stand-alone Part D plan from a private insurer.

Two Part D figures are set nationally for 2027: the out-of-pocket cap is $2,400 (it is $2,100 in 2026), and the most any Part D plan may charge as a deductible is $700. The Part D base beneficiary premium used in the late-enrollment penalty calculation is $41.33; actual plan premiums are set plan by plan. Annual Enrollment runs October 15 – December 7, 2026, with choices taking effect January 1, 2027.

How should Californians compare Medigap policies for 2027?

The plan letters are federally standardized, so Plan G from one insurer covers the same Medicare cost-sharing items as Plan G from another insurer. What differs is the premium, the insurer's rating method (how premiums change over time), customer service and whether the insurer uses medical underwriting for a given applicant.

The Medicare Plan Finder at medicare.gov lets a person enter a ZIP code, see the insurers listed for that area, and request premium quotes. Each insurer's own documents (outline of coverage, application) show the specific terms. The Social Security Administration announced a 3.6 percent cost-of-living adjustment for Social Security benefits payable beginning January 2027, which is separate from any Medigap premium.

Where can Californians get free help with Medigap questions?

Free, personalized help is available from Medicare itself. Medicare.gov has a Medigap policy search and plain-language explanations of each lettered plan, guaranteed-issue rights and the six-month open enrollment window. The 1-800-MEDICARE line (1-800-633-4227) is staffed 24 hours a day, seven days a week, and can walk callers through their situation.