S.C. Code Ann. § 6-1-75: Allocation of aid to counties based on population of annexed areas.

Where a portion of one county is annexed to another county, the total amount allocated by the General Assembly under Aid to Subdivisions to the two counties must not exceed the total which would be allocated to the two counties separately. However, the population of the annexed areas must be taken into consideration in determining the proportionate share of the total allocation due to each county.