Who assigns NAICS codes to businesses and how?
"There is no central government agency with the role of assigning, monitoring, or approving NAICS codes for establishments. Individual establishments are assigned NAICS codes by various agencies for various purposes using a variety of methods.
The U.S. Census Bureau assigns one NAICS code to each establishment based on its primary activity (generally the activity that generates the most revenue for the establishment) to collect, tabulate, analyze, and disseminate statistical data describing the economy of the United States. Generally, the U.S. Census Bureau's NAICS classification codes are derived from information that the business establishment provided on surveys, census forms, or administrative records.
Various other government agencies, trade associations, and regulation boards adopted the NAICS classification system to assign codes to their own lists of establishments for their own programmatic needs."
Note: "Title 13, U.S. Code, Section 9 (a) prohibits the U.S. Census Bureau from disclosing individual company activities including NAICS and SIC codes." A public company is also not required to publicize its NAICS code. Independent research firms may assign NAICS codes to companies but accuracy, comprehensiveness, and consistency are not guaranteed.
