S.C. Code § 12-54-43
2000 Act No. 399, Section 3.Z., provides, in pertinent part, as follows:
"This section takes effect upon approval by the Governor, or as otherwise stated, except that ... subsection J.1. applies to taxable periods ending after December 31, 1999; subsection J.2. applies to tax returns due after October 31, 2000, and does not affect an action or proceeding commenced or a right accrued before October 1, 2000 ...."
2005 Act No. 161, Section 16.B, provides as follows:
"This SECTION [adding subsection (L)] takes effect upon approval by the Governor and is applicable for tax years beginning after December 31, 2005."