The Standard Industrial Classification SIC is a system for classifying industries or businesses by a 2, 4, 6 or 8-digit code. Established in the United States in 1937, it is used by government agencies to classify industry areas. When you establish a business, you must select your SIC or “type” of business.
The North American Industry Classification System (NAICS) is used by businesses and governments to classify and measure economic activity in the United States, Canada, and Mexico. NAICS is a 6-digit code system that is currently the standard used by federal statistical agencies in classifying establishments (individual business locations). NAICS organizes establishments into industries according to the similarity in the processes used to produce goods or services.
Basically, they are interchangeable and are the primary way for us to segment our business data. If a customer is trying to find a specific industry, we must first identify the SIC codes under which that business falls.