Nasdaq use ICB (Industry Classification Benchmark) which is mantained by the FTSE Group.Many companies generate income from different types of businesses. The ICB system takes into account the company's principal activity or the business area that generates the largest proportion of revenue for the company.
Industry classification provides a dynamic structure to benchmark share performance against others in your business. It puts your company in focus as professional investors follow the markets by industry. It also makes it possible to analyze where an industry stands in a broader context.
ICB is a widely used global standard for company classification, with four levels of granularity - industry, supersectors, sectors and subsectors. At the top level are these ten industries