Press release from Wisconsin Department of Revenue:
Starting June 1, the Wisconsin Department of Revenue will require My Tax Account users to update the North American Industry Classification System (NAICS) code associated with a business.
We need Wisconsin businesses to update their NAICS codes so we can better communicate directly with business sectors on tax law or filing changes and correctly estimate the fiscal impact of tax law changes. The United States Office of Management and Budget regularly updates the codes, so some businesses currently may not have correct codes.
The first My Tax Account user to log in for a business, including a third-party, will be prompted to update its 6-digit NAICS code. The user must either confirm the current NAICS code, if available, or select a different code using the search feature available. Once the code is updated for a business, no other users will be prompted to do the update.
The NAICS is a 6-digit code system used by businesses and governments to classify and measure economic activity in the United States, Canada, and Mexico. For more information, go to: https://www.census.gov/eos/www/naics/faqs/faqs.html