The two most common industrial classification systems you'll encounter are the NAICS and the SIC. Both are hierarchical, organized into broad industrial categories, each divided into more specific industries. Fortunately, the following list of NAICS codes includes virtually all types of consulting firms, and in most cases, you can refer to the code closest to the services your consulting firm offers. The definition of NAICS Code 541611 is that establishments that are primarily engaged in providing advice and operational assistance to companies and other organizations on administrative management issues, such as financial planning and budgeting, capital and asset management, records management, office planning, strategic and organizational planning, site selection, creating new businesses, and improving business processes.
Companies with this NAICS Code include establishments that are mainly dedicated to providing services related to information technology (except for custom programming, system integration design, and facility management services). Under this code, companies are defined as establishments that are primarily engaged in providing advice and assistance to companies and other organizations on environmental issues, such as the control of environmental pollution caused by pollutants, toxic substances, and hazardous materials. IT consulting is classified under NAICS Code 541690 (Other Scientific and Technical Consulting Services). The NAICS Management Consulting Services Code, on which management consulting services are based, is 54161, which classifies more specific types of management consulting services.
If a company is not classified under any other business consulting code, the appropriate code is the code 541618 of the NAICS (Other Management Consulting Services). If a medical consulting company is a doctor's office (excluding mental health doctors), the corresponding NAICS code is 621111.