Medicare Supplement

Medigap in Thousand Oaks: what the Oct. 15–Dec. 7 window does not change

Thousand Oaks, Calif. — As the Annual Enrollment Period opens Oct. 15, 2026 and runs through Dec. 7, a lot of local mail is going to talk about "the deadline." For Medicare Supplement — Medigap — most of that urgency does not apply. Medigap has no annual window. You can apply for a Medigap policy any month of the year. What the fall window actually decides is your Medicare Advantage and Part D coverage for 2027 — and those choices can, in turn, affect whether a Medigap insurer has to sell you a policy without asking health questions.

Here is what Thousand Oaks readers should understand before they act.

What Annual Enrollment does — and does not — do for Medigap

The Annual Enrollment Period (AEP) is for Medicare Advantage and Part D. Between Oct. 15 and Dec. 7, 2026, you can join, drop, or switch those plans, and the change takes effect Jan. 1, 2027. If you do nothing, your current plan renews as described in its Annual Notice of Change.

Medigap is different. It is sold by private insurers to work alongside Original Medicare (Parts A and B), and it is regulated under its own set of rules. There is no October–December Medigap window. You can apply in April or July just as easily as in November.

What AEP can do is put you in a position where you want a Medigap policy — for example, if you decide during the window to leave a Medicare Advantage plan and return to Original Medicare on Jan. 1, 2027. That is when the underwriting question comes up.

Medical underwriting in California, in plain terms

Outside of a protected enrollment right, a Medigap insurer in California can ask about your health and can decline you or charge more based on what they find. This is called medical underwriting.

You have a guaranteed right to buy Medigap — no health questions — in a few specific situations under federal law:

• Your Medigap Open Enrollment Period: the six months that start the month you are 65 or older and enrolled in Part B. This is the strongest protection and only happens once.
• Certain guaranteed-issue situations, such as your Medicare Advantage plan leaving your service area or ending its contract.
• A federal "trial right" if you joined a Medicare Advantage plan when you first became eligible for Medicare, or dropped a Medigap policy to try Medicare Advantage for the first time, and you decide to switch back within 12 months.

California also has its own Medigap protections, including a birthday-month rule that lets many enrollees change to an equal or lesser Medigap plan each year without underwriting. Rules and timing can change, so confirm the current version with California's HICAP (the state SHIP) or the California Department of Insurance before you cancel anything.

Moving from Medicare Advantage back to Original Medicare

Thousand Oaks is in Ventura County, where 35 Medicare Advantage plans from 10 carriers are offered for 2026 (the plans are shown in the table below). Some people will look at their Annual Notice of Change this fall and decide Medicare Advantage no longer fits. Here is the sequence that matters:

1. During AEP (Oct. 15 – Dec. 7, 2026), you use Medicare.gov, 1-800-MEDICARE, or your plan to disenroll from the Medicare Advantage plan and return to Original Medicare, effective Jan. 1, 2027. 2. Because Original Medicare has no out-of-pocket maximum on its own, most people also want a standalone Part D drug plan and a Medigap policy. 3. You apply for the Medigap policy separately, directly with the insurer. Whether that insurer must accept you without underwriting depends on whether you qualify for a guaranteed-issue right, a trial right, or a California-specific protection.

There is also a Medicare Advantage Open Enrollment Period from Jan. 1 – March 31, 2027, for people already in a Medicare Advantage plan who want to switch to a different one or return to Original Medicare. It does not, on its own, guarantee acceptance into a Medigap policy.

The standardized letters sold in California

Medigap is standardized by the federal government. Every policy with the same letter covers the same core benefits, no matter which insurer sells it. What can differ is the price, the customer service, and whether that carrier is even accepting new applicants at the moment.

For people newly eligible for Medicare today, these letters are available: A, B, D, G, high-deductible G, K, L, M, and N. Plans C and F can still be purchased only by people who were eligible for Medicare before Jan. 1, 2020.

The table below lists every Medigap insurer we track selling in California and the letters each one offers. Well-known names on that list — in alphabetical order — include AARP – UnitedHealthcare Insurance Company, AFLAC, Anthem BlueCross – California, Blue Shield of California Life & Health Insurance Company, Humana Insurance Company, Mutual of Omaha (United World Life), State Farm Mutual Automobile Insurance Company, and USAA Life Insurance Company, among others. Because the benefits inside each letter are identical by law, shopping Medigap is largely a question of price and service — not of one company's "Plan G" being richer than another's.

What to do this fall in Thousand Oaks

• Read your Annual Notice of Change. It arrived in September and tells you what changes for your 2027 plan.
• Don't cancel a Medigap policy until a new one is issued. Applying does not guarantee approval outside a protected window.
• Know the 2027 Part D figures CMS has confirmed: the out-of-pocket cap rises to $2,400 (from $2,100 in 2026), and the maximum deductible rises to $700 (from $615 in 2026). The 2027 Part B premium, Part B deductible, and IRMAA brackets have not been announced yet; CMS usually publishes them in the fall.
• Get help. California's HICAP counselors are free and unbiased, and 1-800-MEDICARE can walk you through timing.