S.C. Code Ann. § 34-21-390: Valuation of securities in fund.

At least once every three months the trust institution administering a common trust fund shall determine the value of the securities in the common trust fund. No participation shall be admitted to or withdrawn from the common trust fund, except on the basis of such valuation and on the date of the determination of such valuation or, if permitted by the plan, within ten business days subsequent to the date of such determination.