Standard Industrial Classification (SIC) codes are business classification codes that the U.S. government assigns to businesses. SIC coding is used primarily to classify a company's main industry and line of business.
The primary SIC code for a company defines the company's core industry. A business's main line of work can overlap and fall into many different industries. The primary code classifies the company's most relevant industry and function.
Primary vs. Secondary
Apart from primary SIC codes, a company can have up to five secondary codes. Secondary codes classify other industries that the company may be involved in that are not part of its main industry, or which overlap from its main line of business.
Reading a SIC Code
SIC codes consist of four digits. The first two numbers of the code classify the major industry group, the third number further defines the industry group and the last digit is the company's main industry.
Uses of Codes
SIC classification primarily assists with data collection, presentation and analysis. The structured code classification with these codes allow for a uniform presentation of data by the government, and state agencies as well as independent organisations.