The Corporate Income Tax rate on C Corporations is 5% on South Carolina taxable income. 

• ​The starting point in determining South Carolina taxable income is your federal taxable income with certain South Carolina modifications subject to allocation and apportionment. 
• Multi-state corporations must directly allocate certain nonbusiness related items of income and gains and losses and apply an apportionment ratio to all income remaining after allocation. 
• Corporations involved in manufacturing, selling or otherwise dealing with tangible personal property (except for repair) use or an apportionment ratio based on sales alone. 
• Most other corporations including financial businesses, service businesses, doctors, architects, installation and repair businesses and contractors use a gross receipts apportionment ratio. 
• Railroads, telephone companies, pipeline companies, airlines, and shipping lines, use special apportionment methods.

Filing a Corporate Tax return automatically registers you with the SCDOR. If this is your first return filed, check the Initial Return box on the front of the SC1120. 

Once your Corporate Income Tax account is registered with the SCDOR, we will send you a Corporate Registration Filing Requirements letter (SC1070). This letter includes important information about your Corporate Income Tax filing requirements.  To avoid processing delays, be sure to include your FEIN on all returns, payments, and correspondence sent to the SCDOR.

You are required to file a ​CL-1 (Initial Annual Report of Corporations) and pay the $25 initial Corporate License Fee within 60 days of doing business or using capital in the state of South Carolina. This fee should be paid to the SCDOR if you have not already done so with the South Carolina Secretary of State (SCSOS​).

The SCDOR has no role in requiring a Certificate of Authority with the SCSOS​ to do business in South Carolina. Questions about who is required to have a Certificate of Authority should contact the SCSOS. The requirements for a Certificate of Authority are in Chapter 15 Title 33 of the South Carolina Code of Laws.