If you wish to target a market purposefully, then Extended SIC Codes work best. An Extended SIC Codes provide a more detailed targeting option than a general 4-digit SIC or NAICS Code does. These are basically a 6-digit system of 7-digit or the 8-digit system.
At present, there are mostly 1066 industries in NAICS and about 10,000 industry codes available by using the Extended SIC Code System, if searched. These codes make sure you find the precisely focused business list of your market.
As the U.S. Government knowing the certain disadvantages of the official 4-digit SIC Code system, they allowed for the development and usage of Extended SIC Codes by private companies and agencies.
The creation of these Extended SIC Code Systems enabled marketers to aim at their campaigns on a more focused level and avoid unnecessary fund wastage. Another benefit of this code system is the continuous updating of the emerging industries by the private industry. They are most beneficial for marketing purposes.