CMS Pub. 100-01, ch. 2, § 40.7.8

If an individual did not sign up for Part B when first eligible, the individual may have to

pay a late enrollment penalty for as long as the individual has Medicare. The individual’s

monthly premium for Part B may go up 10% for each full 12-month period that the

individual could have had Part B, but did not sign up for it.

For individuals enrolling using the SEP Related to Coverage Under Group Health Plans,

the Part B LEP is calculated by adding the months that have elapsed between the close of

the individual’s IEP and the end of the month in which the individual enrolls. For

enrollments after your IEP has ended, months where you had group health plan coverage

are excluded from the LEP calculation.

For individuals enrolling using an Exceptional Conditions SEP, the International

Volunteers SEP, or the SEP for Certain TRICARE Beneficiaries, no LEP will be applied.

For individuals enrolling using the D-SEP, the Part B LEP is calculated by adding all

months during which the large group health plan (LGHP) was secondary payer

beginning with the end of the IEP, or the date LGHP coverage began.