Section 408.4 - Payment obligations(a)Month for which payment is due.(1) A payment is due for each month, beginning with the first month of SMI coverage and continuing through the month of death or, if earlier, the month in which coverage terminates.(2) A premium is due for the month of death, if SMI coverage is still in effect, even though the individual dies on the first day of the month.(b)Overdue premiums.(1) Overdue premiums constitute an obligation enforceable against the enrollee or the enrollee's estate.(2) Overdue premiums are collected-(i) By deduction from social security or railroad retirement benefits or Federal civil service annuities;(ii) Directly from the enrollee or the enrollee's estate; or(iii) By offset against any SMI payments payable to the enrollee or the enrollee's estate.(3) Interest is not charged on overdue premiums, except under a State buy-in agreement, as provided in § 408.6(c)(4) .(c)Premiums not required for certain kidney donors.(1) No premiums are required for SMI benefits related to the donation of a kidney if the donor is not an enrollee.(2) A kidney donor who is an enrollee is not relieved of the obligation for premiums.52 FR 48115, Dec. 18, 1987; 53 FR 4159, Feb. 12, 1988