While Medicare is the only insurance for some beneficiaries, it’s also common to have Medicare along with another type of insurance in order to reduce out-of-pocket costs. When that happens, there’s a predetermined coordination of benefits, in which one policy is the “primary insurance” and one is the “secondary insurance.” The primary insurance pays first, and the secondary insurance may then make additional payments before the policyholder owes money. That might include some portion of your deductibles or copayments, but it may not.
When is Medicare Primary Insurance?
If you don’t have any other insurance, Medicare will always be your primary insurance. In most cases, when you have multiple forms of insurance, Medicare will still be your primary insurance. Here are several common instances when Medicare will be the primary insurer.
If you have job-based insurance from a company with fewer than 20 employees
Your group insurance plan is the secondary insurer, so you should enroll in Medicare Part B before your group plan will pay its portion of the claim.1
If you have retiree insurance through a former company
Some retiree insurance plans do not pay for medical costs if you’re eligible for Medicare and don’t enroll. To get the details of how Medicare will work with your retirement health benefits, get a copy of your plan’s benefit materials.2
If you have COBRA insurance after leaving a company where you had health insurance
You may decide to keep only Medicare, and not pay for additional coverage through COBRA.
If you have a disability
If you have a disability, you’re younger than 65, and your employer-based health plan has fewer than 100 employees, Medicare will pay first.3
If you have end-stage renal disease (ESRD)
Even if you have a group health plan, Medicare is the primary insurer as long as you’ve been eligible for Medicare for 30 months or more. 4
If you have TRICARE
If you are on inactive duty, Medicare is the primary insurer, but TRICARE will pay the bills if you get services from a military hospital or other federal health care provider.5
If you have Medicaid
Medicaid is always the secondary insurance if you have Medicare.6
When is Medicare Secondary Insurance
While Medicare usually is the primary insurance, there are some instances when Medicare is secondary. Two common instances are:
If you have job-based insurance from an employer with 20 or more employees
This is the case whether you get insurance through your company or your spouse’s employer. Employers must offer workers age 65 or older the same health benefits that they offer to the rest of employees.7
If you receive workers’ compensation
Your workers’ compensation insurance will be primary for any services or items related to your workers’ compensation claim. Medicare will serve as your primary service for all covered medical expenses unrelated to that claim.8
When Is Medicare Primary and Secondary?
| You have Medicare and… | Primary insurance | Secondary insurance |
| …Medicaid | Medicare | Medicaid |
| … You are 65 or older and have a group health plan through an employer with 20 or more employees | Group health plan | Medicare |
| … You are 65 or older and have a group health plan through an employer with fewer than 20 employees | Medicare | Group health plan |
| … You and a retiree health plan through a former employer after you retire | Medicare | Retiree coverage |
| … You are disabled and have a group health plan through an employer with 100 or more employees | Group health plan | Medicare |
| … You are disabled and have a group health plan through an employer with fewer than 100 employees | Medicare | Group health plan |
| … You have veteran’s benefits | Medicare pays for Medicare-covered services Veteran’s Affairs pays for VA-authorized services | Typically does not apply |
| … You have COBRA coverage | Medicare | COBRA |
| … You have TRICARE and are active-duty military | TRICARE | Medicare |
| … You have TRICARE and are inactive duty military | Medicare | TRICARE may pay |
| … You have been in an accident and insurance is involved | No-fault or liability for services related to the accident claim | Medicare |
| …. You are covered by workers’ compensation | Workers’ compensation for services or items related to the workers’ compensation claim | Typically does not apply |
| … You have end-stage renal disease and a group health plan and have been eligible for Medicare for 30 months or less | Group health plan | Medicare |
| … You have end-stage renal disease and a group health plan and have been eligible for Medicare for more than 30 months | Medicare | Group health plan |
| … You have end-stage renal disease and COBRA coverage and have been eligible for Medicare for fewer than 30 months | COBRA | Medicare |
| … You have end-stage renal disease and COBRA and have been eligible for Medicare for more than 30 months | Medicare | COBRA |
| … You are covered under the Federal Black Lung Benefits Program | The Federal Black Lung Program pays for services related to Black Lung | Medicare |
When can you delay enrolling in Medicare?
If you have health insurance through your or your spouse’s employer, and that employer has more than 20 employees, you may be able to delay enrolling in Medicare without paying a penalty. In that case, even if you did enroll in Medicare at age 65, it would be a secondary insurance and only kick in after your primary insurance paid its share of your claims. To avoid penalties after you (or your spouse) leave your job, you’ll need to enroll in Medicare within eight months. 9
If your employer has fewer than 20 employees, Medicare would be your primary insurance, and you should enroll during your Initial Enrollment Period. If you miss this chance to enroll in Medicare Part B, you may face a late enrollment penalty. Every year that you delay enrollment in Medicare Part B, your premiums will go up 10% unless you or your spouse have insurance through work.10
Next Steps
While having multiple forms of health insurance is a fortunate situation, it can also be confusing to determine which one is your primary and which is your secondary – or whether it makes sense to continue paying for both policies. Figuring out which insurance is your primary, however, will make it easier for you to manage your insurance going forward.
