What Medicare Supplement Companies Do

Medicare Supplement insurance, also called Medigap, is sold by private insurance companies — not by Medicare itself. These companies write policies that pay some or all of the costs Medicare doesn't cover: copayments, coinsurance, and deductibles. When you have both Medicare and a Medigap policy, you send your Medicare claim to Medicare first, then the insurance company pays its share of what's left.

The insurance company you choose matters because premiums, customer service, and financial stability vary widely. However, the actual coverage you get does not vary — the federal government sets what each Medigap plan type (called Plan A, Plan B, Plan C, and so on) must cover. A Plan G from one company covers exactly the same things as a Plan G from another company. What differs is the price you pay each month and how straightforward the company is to work with.

Key Takeaways

  • Medigap policies are sold by private insurance companies, and the plan type you choose (A through N) determines what Medicare gaps are covered, not which company you pick.
  • Different companies charge different premiums for the same plan type, so comparing quotes from at least three companies can save you hundreds of dollars per year.
  • You have a may provide issue period of 63 days after you turn 65 and enroll in Medicare Part B, during which any company must sell you a policy without medical underwriting.
  • Outside the may provide issue period, some companies will deny you or charge more based on your health history, so timing your purchase matters.
  • The National Association of Insurance Commissioners (NAIC) publishes complaint ratios for each company, which you can use to compare customer service records.

How to Find and Compare Medigap Companies

Start by deciding which plan type meets your needs — this is separate from choosing a company. Plan F and Plan G are the most popular because they cover the largest share of Medicare's gaps. Once you know the plan type you want, get quotes from at least three companies. Most companies let you request a quote online or by phone without committing to anything.

The Medicare.gov Plan Finder tool shows you which companies sell Medigap in your state and ZIP code. You enter your plan type and birth date, and it lists available policies with their monthly premiums. This tool does not sell insurance; it only shows you what is available. You then contact the company directly to buy.

When you compare quotes, look at the monthly premium, but also check the company's complaint ratio. The NAIC publishes this data on its website — it shows how many complaints each company received per 1,000 policies sold. A lower ratio suggests fewer customer service problems. You can also read reviews on your state's insurance department website, though remember that unhappy customers are more likely to leave reviews than satisfied ones.

The may provide Issue Period and When You Can Buy

If you are turning 65 and enrolling in Medicare Part B, you have a may provide issue period of 63 days starting the month you turn 65. During this window, any Medigap company must sell you any plan you want, and they cannot deny you or charge more because of your health. This is the easiest and cheapest time to buy Medigap.

If you miss this window, you can still buy Medigap, but the company can require medical underwriting — meaning they review your health history and may deny you, charge you more, or exclude certain conditions. Some companies are more willing to underwrite older applicants than others, which is another reason to compare before you buy. A few states have additional may provide issue periods if you lose employer coverage or move, so check your state's insurance department website.

If you already have Medigap and want to switch companies, you can usually do so without medical underwriting as long as you stay with the same plan type. However, some states limit your right to switch, so contact your current company or your state insurance department before you change.

How Premiums Are Set and What They Cover

Medigap companies use three main methods to set premiums: community-rated (everyone in your state pays the same), issue-age-rated (your age when you buy determines your rate), and attained-age-rated (your rate goes up as you get older). Community-rated is usually cheapest when you first buy, but attained-age-rated can be cheaper over time if you stay healthy. Ask the company which method they use before you buy.

Your premium pays for the gaps in Medicare coverage that your plan type includes. For example, a Plan G covers Medicare Part B coinsurance (the 20% you normally pay after you meet your deductible), your Part A hospital deductible, and skilled nursing facility coinsurance. It does not cover things Medicare does not cover — dental, vision, hearing aids, or long-term care. If you need those services, you would buy a separate policy or pay out of pocket.

Premiums can change each year. The company must notify you of any increase at least 30 days before it takes effect. If your premium rises sharply, you have the right to switch to a different company or plan type, though you may face medical underwriting if you are outside your may provide issue period.

What Happens When You Use Your Medigap Policy

When you receive medical care, your provider bills Medicare first. Medicare pays its share and sends you an Explanation of Benefits (EOB) showing what it paid and what you owe. You then send that EOB to your Medigap company, and they pay their share directly to you or to the provider, depending on the company's agreement with the provider.

Most of the time this process is automatic — your provider has a contract with your Medigap company and submits the claim for you. You may see a bill from the provider, but once the Medigap company pays, your out-of-pocket cost should match what your plan covers. If you receive a bill you think is wrong, contact your Medigap company's customer service line. The phone number is on your insurance card.

If you travel outside the United States, Medicare and most Medigap policies do not cover care you receive abroad. Some Medigap companies offer travel coverage as an add-on for an extra premium, but it is limited. If you travel frequently or for extended periods, ask your company what coverage is available.

Switching Companies or Changing Your Plan

You can switch Medigap companies or change to a different plan type during the annual open enrollment period (October 15 to December 7) without medical underwriting, as long as you have had continuous Medigap coverage. Outside this window, you may face medical underwriting or denial if you have health conditions.

If you are switching companies but keeping the same plan type, the process is usually straightforward: you buy the new policy, and it becomes effective on a date you choose (usually the first of the month). Your old policy ends on the day before. Make sure there is no gap in coverage. If you are changing to a different plan type, the same rules explore, but you should compare premiums carefully because a different plan type may cost more or less.

Some people switch companies every year to chase the lowest premium. This is allowed, but keep in mind that you may face medical underwriting if you switch outside the may provide issue period or annual open enrollment. Also, switching means you may have a new customer service team and new provider networks, which can be inconvenient.

Red Flags and How to Avoid Scams

Scammers sometimes pose as Medigap companies or Medicare representatives to steal personal information or money. Be cautious of unsolicited calls, emails, or door-to-door visits offering Medigap coverage. Medicare and legitimate Medigap companies will not call you out of the blue to sell you a policy.

If someone contacts you claiming to represent a Medigap company, hang up and call the company directly using the phone number on your Medicare card or the number listed on Medicare.gov. Never give your Social Security number, bank account, or credit card information to someone who called you first. Legitimate companies ask for this information only after you have initiated contact and decided to buy.

Check that any company you buy from is licensed in your state. Your state's insurance department website lists all licensed insurers and has a complaint process if something goes wrong. If you suspect fraud, report it to your state insurance commissioner or to Medicare at 1-800-MEDICARE.

Frequently Asked Questions

Can I buy Medigap if I have a pre-existing condition?

Yes, if you are within 63 days of turning 65 and enrolling in Medicare Part B. During this may provide issue period, companies cannot deny you or charge more based on your health. Outside this window, some companies will underwrite your process and may deny you or exclude certain conditions. Your state may have additional protections; check your state insurance department website.

What is the difference between Medigap and Medicare Advantage?

Medigap works alongside Original Medicare (Parts A and B) and covers gaps in that coverage. Medicare Advantage is an alternative to Original Medicare sold by private companies; it includes hospital and doctor coverage but usually has networks and prior authorization requirements. You cannot have both at the same time. Medigap is generally better if you travel or see many different doctors.

Do I have to buy Medigap, or can I just use Medicare?

You are not required to buy Medigap. Original Medicare covers a lot, but you pay copayments, coinsurance, and deductibles out of pocket. Many people find these costs add up and choose to buy Medigap to reduce them. Others use Medicare Advantage instead. The choice depends on your health, budget, and how much predictability you want in your costs.

What happens to my Medigap policy if I move to a different state?

Your current policy may not be available in your new state because Medigap companies operate in different states. You have 63 days after you move to buy a new Medigap policy in your new state without medical underwriting. Contact your current company to learn about they operate in your new state, or use Medicare.gov to find companies that do.

How do I know if a Medigap company is financially stable?

Check the company's financial rating on the A.M. Best website or your state insurance department website. These ratings tell you whether the company has enough money to pay claims. You can also look at the company's complaint ratio on the NAIC website. A company with low complaints and a strong financial rating is generally a safer choice.