For purposes of this subpart, the following definitions apply:

SMI premium surcharge means the amount that the standard monthly SMI premium is increased for late enrollment or for reenrollment as specified in §§ 408.22 through 408.25.

SMI premium surcharge agreement means a written arrangement between the Secretary and a State or local government agency to pay, on a quarterly, monthly, or other periodic basis, a lump sum for the SMI premium surcharge amounts due for a designated group of eligible enrollees.