If a beneficiary does not buy Part A when they first become eligible, they may have to pay a monthly premium penalty. The premium is subject to a 10% increase payable for twice the number of full twelve-month periods a beneficiary could have been enrolled in Part A but was not. The 10% premium surcharge will apply only after 12 months have elapsed from the last day of the Initial Election Period (IEP) to the last date of the enrollment period that was used to enroll. In other words, if it has been less than 12 months, the penalty will not apply. This penalty will not apply to beneficiaries who are working and covered by a group health plan through their employer or union, or during the 8-month period that begins the month after the employment ends or the group health coverage ends, whichever happens first.