S.C. Code Ann. § 12-16-730: Payment of tax.

(A) Every person required to file a return reporting a generation-skipping transfer under applicable federal statutes and regulations shall file a return with the department on or before the last day prescribed for filing the federal return. For purposes of this article the requirements for filing a return are satisfied by filing a duplicate copy of the federal return.

(B) The tax imposed by this section is due upon a taxable distribution or taxable termination as determined under applicable provisions of the federal generation-skipping transfer tax. The person liable for payment of the federal generation-skipping transfer tax is liable for the tax imposed by this article. The tax must be paid to the department on or before the last day allowed for filing a return hereunder. Interest computed as provided in Section 12-54-25 accrues on the amount of unpaid tax from the day after the last day for filing a return until the date of payment.