Medicare Supplement

Riverside on Original Medicare? Here's how Medigap fits

RIVERSIDE, Calif. — If you have Original Medicare and you live in Riverside, a Medigap policy is the private insurance that helps pay the out-of-pocket costs Medicare Parts A and B leave behind. In California, those policies come in standardized "letter" plans set by federal rules, so what you are really choosing between is a set of letters — and the insurer that sells them.

Here is a plain-English look at which Medigap letters a Riverside resident can buy today, how they fit alongside Original Medicare and a Part D drug plan, and where to check California-specific rules before you sign anything.

The plan letters you can buy in California

California follows the federal standardized Medigap chart. If you are newly eligible for Medicare — meaning your Part A started on or after January 1, 2020 — the letter plans available to you are:

• Plan A
• Plan B
• Plan D
• Plan G
• High-deductible Plan G
• Plan K
• Plan L
• Plan M
• Plan N

Plans C and F are still in force for people who were eligible for Medicare before January 1, 2020, but they are not sold to anyone new. If you see them advertised, that is who they are meant for.

Each letter is a fixed benefit package written by federal law. That means a Plan N from one company covers exactly the same Medicare cost-sharing as a Plan N from any other company. The differences you shop on are the monthly premium, how the insurer raises rates over time, and the extras (like a 24-hour nurse line) that sit outside the standardized benefits.

How Medigap fits with Original Medicare and Part D

Medigap is designed to pair with Original Medicare, not replace it. Medicare pays first, and your Medigap policy picks up some or all of what is left — things like the Part A hospital deductible, coinsurance days, and the 20% you would otherwise owe on Part B services. The higher the letter's coverage, generally the higher the premium.

A few points that trip people up in Riverside:

• Medigap does not cover prescription drugs. If you want drug coverage, you enroll in a stand-alone Medicare Part D plan.
• You cannot use a Medigap policy with a Medicare Advantage plan. If you are on Advantage now and want to switch to Original Medicare plus Medigap, timing and medical underwriting rules matter.
• Medigap policies sold today are "guaranteed renewable." The insurer cannot drop you for using it.

For 2026, Part D has an annual out-of-pocket cap of $2,100 and a maximum deductible of $615. The old coverage gap ("donut hole") has been gone since 2025 — Part D now has three phases. There is also a Medicare Prescription Payment Plan option that lets you spread drug costs across the calendar year in monthly installments. Higher-income enrollees (above $109,000 for a single filer in 2026) also pay an IRMAA surcharge on Part B and Part D.

The California rules that shape your choice

A few state-level details matter when you shop:

• Open enrollment for Medigap. Under federal law, you have a 6-month Medigap Open Enrollment Period that begins when you are 65 or older and enrolled in Part B. During this window, insurers cannot turn you down or charge you more because of your health.
• California's "birthday rule." California gives current Medigap policyholders an annual window tied to their birthday to switch to another Medigap policy with equal or lesser benefits, without medical underwriting. The exact length of the window and the details of what qualifies are set by state law and can change, so confirm the current rules with the California Department of Insurance or HICAP before you switch.
• Guaranteed issue rights. Beyond the federal list of guaranteed-issue situations (for example, if your Medicare Advantage plan leaves your area), California may add protections of its own. Again, check with the state.

Outside these protected windows, insurers in California can use medical underwriting on Medigap applications — meaning your health history can affect whether you are approved or what you pay.

How Medigap policies are priced

Standardized benefits do not mean standardized prices. In California, insurers may use different pricing methods:

• Issue-age rated — premium is based on your age when you buy the policy.
• Attained-age rated — premium goes up as you get older.
• Community rated — everyone with that policy in the area pays the same premium regardless of age.

Two policies with the same letter can look similar on day one and diverge over the years because of how the insurer prices them. Ask any agent how the specific policy you are considering is rated, and ask for the company's rate history.

Finding insurers that sell Medigap in Riverside

Because we cannot list specific insurers here, use these free, official tools:

• Medicare.gov Medigap policy search. Enter your Riverside ZIP code and it returns the companies licensed to sell each letter plan in your area, along with contact information.
• California Department of Insurance Medigap rate guide. The state publishes a comparison of premiums by insurer and letter plan.
• HICAP (California's SHIP). The Health Insurance Counseling and Advocacy Program gives free, unbiased one-on-one counseling to people on Medicare. Riverside County residents can reach HICAP through the statewide number.
• 1-800-MEDICARE for general Medicare questions, 24 hours a day.