S.C. Code Ann. § 12-2-25

(A) As used in this title and in other titles which provide for taxes administered by the department and unless otherwise required by the context: (1) "partnership" includes a limited liability company taxed for South Carolina income tax purposes as a partnership; (2) "partner" includes a member of a limited liability company taxed for South Carolina income tax purposes as a partnership; (3) "corporation" includes a limited liability company or professional or other association taxed for South Carolina income tax purposes as a corporation; and (4) "shareholder" includes a member of a limited liability company taxed for South Carolina income tax purposes as a corporation. (B) For South Carolina tax purposes: (1) a single-member limited liability company, which is not taxed for South Carolina income tax purposes as a corporation, is not regarded as an entity separate from its owner; (2) a "qualified subchapter S subsidiary", as defined in Section 1361( b)(3)(B) of the Internal Revenue Code, is not regarded as an entity separate from the "S' corporation that owns the stock of the qualified subchapter 'S' subsidiary; and (3) a grantor trust, to the extent that it is a grantor trust, is not regarded as an entity separate from its grantor. (C) For purposes of this section, the Internal Revenue Code reference is as provided in Section 12-6-40(A).