If you were an economist for a firm that wanted to merge, would you argue that the three-digit or five-digit NAICS industry is the relevant market? Why?
North American Industry Classification System (NAICS) is a code system that is currently the standard used by federal statistical agencies in classifying business establishments. NAICS codes array the economy into 20 sectors, which are separated into 99 3-digit subsectors, which are divided into 312 4-digit industry groups, which are further subdivided into 713 5-digit industries, and finally disaggregated into 1066 6-digit U.S. industries. So, the three-digit or five-digit NAICS industry is the relevant market.