What triggers the late enrollment penalty for Medicare Part B?

• A. Enrolling during the Initial Enrollment Period
• B. Not enrolling in Part B when first eligible and without credible coverage
• C. Enrolling in Part B after turning 70
• D. Only if you join a Medicare Advantage plan

Answer: (B)

The main idea is that the late enrollment penalty for Medicare Part B happens when you were eligible for Part B but you didn’t enroll, and you didn’t have credible coverage to bridge that gap. When you miss that window and lack credible coverage, Medicare adds a permanent premium penalty to your Part B cost. The typical amount is 10% for each full 12-month period you could have had Part B but didn’t sign up, and this higher premium remains for as long as you have Part B. You can avoid the penalty by enrolling during your Initial Enrollment Period or by having credible coverage (such as through a current employer plan) at the time you become eligible; once that coverage ends, you should enroll then to prevent penalties. Joining a Medicare Advantage plan isn’t the trigger by itself—the penalty is tied to not enrolling in Part B when eligible and lacking bridging coverage.