how many different industries are there 
different classification systems will group and report industries differently the naics has historically grouped companies into roughly 20 sectors 100 subsectors and over 1 000 six digit naics industry codes 3the bottom linein business and investing industry is a classification that is used to group similar companies these companies have comparable products and services and will often respond in similar ways to macroeconomic trends because of this their stock prices often move up or down at the same time industries can be further grouped into sectors which is a broader classification that includes multiple industries businesses within the same sector may respond similarly to some macroeconomic trends but not others two common classification systems for industries are the north american industry classification system and the global industry classification standard 