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Information about Medicare enrollment

Do you have employees or retirees who are eligible to enroll in Medicare?  

People who are still working (or have retiree, COBRA, or other types of coverage) have important decisions to make about their health coverage when they become eligible for Medicare.  The rules about how other insurance works with Medicare and considerations that people should weigh when deciding whether to enroll in Medicare when they become eligible vary based on:

  • The reason(s) they’re eligible for Medicare;
  • If they or a spouse (or family member, if disabled)  are still working; and
  • If they have employer-sponsored Group Health Plan coverage based on that active employment.  

Enrolling in Medicare late can increase the premium costs for your employees for as long as they have Medicare (and well after they retire from your company), and can result in gaps in coverage.  We ask that you and your benefits administrators become familiar with this information, and direct your employees and retirees to the information on these web pages to help them make informed decisions about their health coverage.

Medicare basics

Medicare Part A, which helps cover inpatient hospital stays, care in a skilled nursing facility, hospice care, and some home health care, is free for most people.  However, Medicare Part B, which covers certain doctors' services, outpatient care, medical supplies, and preventive services, requires the payment of a monthly premium.  

Medicare is health insurance for:

  • People 65 or older;
  • People under 65 with certain disabilities; and
  • People of any age with End-Stage Renal Disease (ESRD) (permanent kidney failure requiring dialysis or a kidney transplant).

If a person who is eligible for premium-free Medicare Part A doesn’t take Medicare Part B when they’re first eligible:

  1. They may enroll later, but only during the General Enrollment Period (GEP) which occurs January 1st through March 31st of every year (unless they qualify for a Special Enrollment Period (SEP)); and
  2. They may have to pay a late enrollment penalty for as long as they have Part B.

Enrolling with a Special Enrollment Period

People age 65 or older who don’t enroll in Medicare Part B when first eligible can enroll later, during the Special Enrollment Period, IF they or their spouse is currently working, and have coverage by an employer or union Group Health Plan (GHP) based on that employment. Those who have Medicare based on disability can enroll if they, their spouse, or their family member is working, and have coverage by an employer or union GHP (with at least 100 employees – also known as a Large GHP) based on that employment.

If eligible for an SEP, a person can sign up for Part B without a penalty:

  • Anytime while he or she is covered by the employer or union group health plan based on current employment.


  • For up to 8 months after the group health plan coverage or the employment ends, whichever happens first.

There are some important things to know about what is and isn’t considered Group Health Plan coverage:

  • COBRA coverage and retiree health plans aren’t considered coverage based on current employment. Individuals who have COBRA and retiree coverage aren’t eligible for a SEP when this coverage ends.
  • Plans that are unavailable to employees (e.g., a plan that only covers self-employed individuals) aren’t considered GHPs. Individuals with this type of coverage aren’t eligible for a SEP.   
  • Paying a stipend for someone to join the Marketplace or other private insurance isn’t considered Group Health Plan coverage, so people with this type of coverage aren’t eligible for a SEP.
  • The Small Business Health Options Program (SHOP) in the Marketplace is Group Health Plan coverage, so people covered by a SHOP plan because of their or their spouse’s current work do have access to a SEP.
  • These rules are different for people with End Stage Renal Disease (ESRD).

Knowing who pays first

In addition to considering whether your employees and retirees will be able to enroll in Part B later through enrollment during a SEP, it’s critical that they consider whether Medicare or their employer-based insurance will pay first or second when deciding whether to enroll in Part B.  If Medicare is primary to other insurance and a person isn’t enrolled in Part B, the other insurance may not pay all the uncovered costs.  

  • If a person is eligible for Medicare due to age, insurance from current work is primary to Medicare if the employer has more than 20 employees.  
  • If a person is eligible for Medicare due to disability, insurance from current work is primary to Medicare if the employer has more than 100 employees
  • If a person is eligible for Medicare due to ESRD, other insurance (from work or from other sources) is primary to Medicare for the first 30 months starting the first month the person is eligible for Medicare whether or not an application has been filed.

Contact us

For questions about enrolling in Medicare, call Social Security at 1-800-772-1213 or visit socialsecurity.gov. TTY users should call 1-800-325-0778.  For those who worked for a railroad or get Railroad Retirement Board (RRB) benefits, call the RRB at 1-877-772-5772 or visit rrb.gov. TTY users should call 1-312-751-4701.

For questions about Medicare benefits, call 1-800-MEDICARE (1-800-633-4227) or visit Medicare.gov.  TTY users should call 1-877-486-2048.

Contact a local State Health Insurance Assistance Program (SHIP) to get free personalized counseling on Medicare coverage, claims, appeals, and help for people with limited income and resources. Call 1-800-MEDICARE or visit Medicare.gov/contacts or visit shiptacenter.org to get the phone number of your local SHIP.

Page Last Modified:
12/01/2021 07:02 PM