What are SIC and NAICS codes?
SIC codes, or Standard Industrial Classification, are four digit codes used to categorize business activities. The hierarchical classification system was developed to ease collection and analysis of data and to help provide consistency in statistical data collected by agencies of the federal government. The system divides activities 11 divisions, then into 83 2-digit major groups, next into 416 3-digit industry groups, and finally into 1,005 4-digit industries.The codes were developed in 1937 but were no longer updated after 1987. In 1997, the SIC system was all but replaced by the NAICS system of classification.
The NAICS system, or North American Industry Classification System, was developed by the Office of Management and Budget (OMB), and adopted in 1997 to replace the SIC manual. It was developed cooperatively by the U.S. Economic Classification Policy Committee (ECPC), Statistics Canada and Mexico's Instituto Nacional de Estadistica y Geografia, to allow for better comparability in business statistics among the North American countries. The NAICS system used six-digit codes at the most detailed industry level. The first five digits are usually but not always the same in all three countries. The first two digits designate the largest business sector, the third digit designates the subsector, the fourth digit designates the industry group, the fifth digit designates the NAICS industries, and the sixth digit designates the national industries.
The sources below will help you search for codes as well as search for data using SIC and/or NAICS codes.