Medicare Supplement plans, also known as Medigap, are a private health insurance option that supplements your original Medicare coverage. This means that a Medicare Supplement Plans helps to pay some of the health care costs that the original Medicare does not cover. In other words it bridges or fills the gap between the policy coverage of the original Medicare and the total amount payable. A Medicare supplement policies sometimes may also cover certain things that the original Medicare does not cover at all. The point of having a Medicare Supplement plan is to help you pay the remaining amount of the medical cost that is not paid by your original Medicare policy.
Though Medicare Supplement Plans are not directly under government supervision or administration but still every Medigap policy must follow certain state laws and must be clearly identified as “Medicare Supplement Insurance”. According to the rules the Medigap insurance companies can sell only 12 standardized Medigap policies. These policies are identified under the letter cover from A through L. And it is also to be noted that each Medigap policies must offer the same basic benefits, irrespective of whatever company may be selling them. The only thing that can differ from company to company is the amount of premium payable by the beneficiary. The point is that if you purchase a Medigap policy from any company under any letter cover the benefits must be same as provided by other companies under the same letter cover, for example, if you want to purchase a policy under the letter cover C or D, the policy coverage and the benefits would be the same no matter which company you may choose.
In most of the cases the Medicare Supplement Insurance companies can only sell standardized Medigap policies. It is also that the companies must mention the specific benefits that they offer so that you can easily compare them. It may be that each and every company may not offer every Medigap plans A through L, but they are bound to provide clear information about the policies they are dealing with. But the fact is that each company must provide Medigap plan A if they wish to offer any other Medicare Supplement Plans. However to sell the rest of the policies should be decided by the company themselves, although law might affect which ones they offer.
You should also note that once you purchase a Medigap Insurance plan the insurance company must keep renewing it. And they also cannot change the policy coverage or the benefits that they promised to provide while purchasing the plan unless there is any failure on your part in paying the premium. However, the company can increase the rate of premium but that too with prior notice. When that happens, it is a good idea to shop around for new coverage, to see if another company will offer you the same plan at a better rate.

Wiley Long is founder and president of Medigap Advisors, and is passionate about helping people navigate the confusing waters of Medicare. He is the author of The Medicare Playbook: Designing Your Successful Health Coverage Strategy, a clear and simple explanation so you can make the most of your Medicare coverage.