The Standard Industrial Classification SIC is a system for classifying industries by the type of activity in which they are primarily engaged with a four-digit code. It is used by government agencies, as well as some in other countries, e.g., by the United Kingdom's Companies House.
The Standard Industrial Classification (SIC) was originally developed in the 1930's to classify establishments by industry. The purpose of this task was to promote the comparability of establishment data to describe the US Economy.
In the United States the SIC code is being supplanted by the six-digit North American Industry Classification System (NAICS code), which was released in 1997; however certain government departments and agencies, such as the U.S. Securities and Exchange Commission (SEC), and Occupational Safety and Health Administration (OSHA) still use the SIC Codes.