The personal representative, trustee, or any affected beneficiary under a will, trust, or other instrument of a decedent who dies or did die after December 31, 2009, and before January 1, 2011, may bring a proceeding to determine the decedent's intent when the will, trust, or other instrument contains a formula that is based on the federal estate tax or generation-skipping tax.
S.C. Code § 62-2-612
2010 Act No. 251, Section 2, provides:
"This act takes effect upon approval by the Governor and applies with respect to decedents dying after December 31, 2009, and before January 1, 2011."