Medicare Advantage and Medicare Supplement insurance are options that may sound similar, but they’re quite different.  They do have one main thing in common: they’re both offered by private insurance companies.

It is illegal for an insurance company to sell you both a Medicare Advantage and a Supplemental (Medigap) policy.

Both require enrollment in Medicare Parts A and B.

Federal annuitants may find that they no longer need their FEHBP coverage when they enroll in a Medicare Advantage health plan.  If that is the case, then they may "suspend" their FEHBP coverage and retain re-enrollment rights during a future federal benefits open season.  To learn more about "suspending" FEHB click here.  If you decide to enroll in a Medicare Advantage plan, you will almost assuredly need to enroll in a plan that includes prescription drug coverage.

There is no similar "suspension" entitlement if you elect to enroll in a Medicare Supplemental or Medigap plan.

For all intents and purposes, when you are retired and enrolled in Medicare Parts A and B, your FEHBP health plan is the secondary payer and acts as your "supplemental" coverage.  This means your FEHB plan generally covers the 20% that's not covered by Medicare.

If you "cancel" your FEHBP coverage, chances are really good that you may NEVER be allowed to re-enroll at a later date.