S.C. Code Ann. § 12-6-3410
(B) In order to qualify for this credit, each of the following criteria must be satisfied:
(1) The qualifying real property costs of the corporate headquarters establishment, expansion, or addition must be at least fifty thousand dollars. Qualifying real property costs are:
(b)
(2) The headquarters establishment, expansion, or addition must result in the creation of:
(D) A headquarters establishment, expansion, or addition which meets the criteria of subsection (B) of this section is entitled to an additional credit equal to twenty percent of cost for tangible personal property if the following conditions are met:
(1) the personal property is:
(2) The establishment, expansion, or addition of a corporate headquarters or research and development facility must result in:
(a) the creation of at least seventy-five new full-time jobs performing either:
(ii) research and development related functions and services.
The jobs must have an average cash compensation level of more than one and one-half times the per capita income of this State based on the most recent per capita income data available as of the end of the taxpayer's taxable year in which the jobs are filled; and
(E)
(1)
(J) As used in this section:
(1) "Corporate headquarters" means the facility or portion of a facility where corporate staff employees are physically employed, and where the majority of the company's financial, personnel, legal, planning, or other headquarters related functions are handled either on a regional or national basis. A corporate headquarters must be a regional corporate headquarters or a national corporate headquarters as defined below:
(b) Regional corporate headquarters must be the sole corporate headquarters within the region and must handle headquarters related functions on a regional basis. For purposes of this section, "region" or "regional" means a geographic area comprised of either:
(5) "Headquarters staff employees" means executive, administrative, or professional workers performing headquarters related functions and services.