Do SIC Codes Change over Time?

SIC Codes have changed many time since their initial creation in 1937, however, the US Government discontinued use of the Standard Industrial Classification System in 1997 and replaced it with the North American Industrial Classification System (NAICS). As such, the codes have not been updated in that time. There are, however, private businesses that have developed six, seven, and eight digit SIC Codes for marketing and identification purposes, and these businesses often update and add codes to their proprietary coding systems to reflect new industries. Those changes, however should not in any way affect your use of four digit SIC Codes for regulatory purposes.