What is a SIC code?
A SIC code is a U.S. industry classification used to identify and group businesses by their primary economic activity. SIC stands for Standard Industrial Classification.
What Is a SIC Code?
SIC code definition
A SIC code is a U.S. industry classification used to identify and group businesses by their primary economic activity. SIC stands for Standard Industrial Classification. The official system is structured from broad Divisions to 2-digit Major Groups, 3-digit Industry Groups, and detailed 4-digit Industries.
SIC preceded NAICS as the federal statistical classification standard, but it remains widely used today in business databases, customer and prospect classification, segmentation, financial and insurance applications, analytics, historical data, and selected government systems.
In simple terms: a SIC code places a business into an industry category so companies, agencies, researchers, and data systems can organize and compare businesses performing similar kinds of activity.
- SIC stands for
- Standard Industrial Classification
- Official structure
- Division → 2-digit Major Group → 3-digit Industry Group → 4-digit Industry
- Detailed industries
- 1,005 official 4-digit industries in the 1987 SIC system
- Official U.S. reference
- 1987 Standard Industrial Classification Manual
- Current use
- Widely used in business data and commercial classification workflows; also retained in selected current government systems
Reviewed by the SICCODE.com Industry Classification Review Team · Updated September 2026
What does SIC stand for?
SIC stands for Standard Industrial Classification. It is a U.S. industry-classification system developed to organize establishments and businesses into standardized industry categories.
The 1987 SIC Manual remains the principal official U.S. SIC reference. NAICS later became the federal statistical standard, while SIC continues to be widely used in business data and selected government systems.
How are SIC codes structured?
SIC uses a compact hierarchy. Broad Divisions are divided into 2-digit Major Groups, 3-digit Industry Groups, and detailed 4-digit Industries.
| Level | Code | Example |
|---|---|---|
| Division | D | Manufacturing |
| Major Group | 25 | Furniture and Fixtures |
| Industry Group | 251 | Household Furniture |
| Industry | 2514 | Metal Household Furniture |
Four digits is the detailed official level. The 1987 SIC system contains 1,005 detailed 4-digit industries. Fewer digits than NAICS does not mean SIC has only a small number of detailed industry categories.
How does SIC classify a business?
SIC organizes businesses through an industry structure that uses a mix of classification principles. Product or service activity is important in many SIC industries, while some parts of the system also reflect production processes, materials, markets, or other industry characteristics.
Industry definitions matter
The correct SIC code should be based on the actual activity being classified, not simply a keyword in the company name or marketing description.
The 4-digit code is the official detail level
A 2-digit Major Group provides a useful industry grouping, the 3-digit level narrows the group further, and the 4-digit code identifies the detailed official SIC industry.
This page explains the SIC definition and basic structure. For detailed classification rules, boundary decisions, complex scenarios, Extended SIC, and governance, use the SIC Classification & Reference Center.
What are SIC codes used for today?
SIC remains an active industry-classification system. Current uses include commercial data workflows, financial and insurance applications, and selected government systems, as well as historical datasets.
Business and commercial uses
- Business database classification
- Customer and prospect segmentation
- Market targeting and business intelligence
- Financial and insurance applications
- Market research and industry analysis
- Vendor and internal data systems
- Historical and longitudinal datasets
Current government and reference uses
- SEC EDGAR company classifications
- SEC Division of Corporation Finance filing-review assignments
- OSHA’s searchable 1987 SIC Manual reference
- Historical federal datasets and series originally coded under SIC
NAICS replacing SIC as the federal statistical standard did not eliminate SIC from current use. SIC remains widely used today in business-data and commercial classification workflows and continues to appear in selected government systems, including SEC EDGAR.
Who assigns SIC codes?
There is no single central authority that maintains one universal SIC code for every business. SIC classifications may be assigned or stored by government agencies, business-data providers, financial or insurance systems, internal databases, and other organizations for their own classification purposes.
For example, the SEC uses SIC classifications in EDGAR to indicate a company’s type of business and to help assign filing-review responsibility within the Division of Corporation Finance.
A SIC code is a classification, not a registration number. Different systems may maintain SIC data independently, so the code associated with a business can depend on the activity, business unit, source, and classification methodology being used.
How do I find a SIC code?
For a straightforward business, use the SIC hierarchy and detailed industry definitions rather than relying on a title match alone.
Describe the primary business activity
Identify the main product, service, or economic activity of the business or establishment being classified.
Search or browse candidate industries
Use the SIC Code Lookup Directory to search by activity, keyword, or code.
Verify the detailed industry definition
Open the candidate code and compare its description, related activities, and neighboring industries before deciding.
For more detailed selection guidance, use How to Choose the Correct NAICS or SIC Code. For difficult classifications, use the SIC Reference Center.
How is a SIC code different from a NAICS code?
SIC and NAICS are separate industry-classification systems with different structures, classification concepts, and current use cases. SIC uses the official hierarchy through 4-digit Industries. NAICS uses a production-oriented framework and a hierarchy through 6-digit U.S. national industries.
The systems organize some industries differently, so SIC-to-NAICS mappings are not always one-to-one. A business can be classified under both systems. Which system is used depends on the dataset, reporting workflow, agency, vendor, or business process involved.
See NAICS vs SIC Codes: What Is the Difference? for the full comparison.
What are Extended SIC codes?
The official U.S. SIC structure ends at 4 digits. Commercial business-data systems may add additional detail below the 4-digit industry to support more specific market segmentation and classification.
The Extended SIC classifications shown at SICCODE.com are continually reviewed and updated to reflect changes in the modern business environment, including emerging industries, new products and services, evolving business models, and activities that are not separately identified in the official 1987 SIC structure. This additional detail supports more precise industry segmentation while preserving the official 4-digit SIC code as the underlying classification anchor.
Important: Extended SIC classifications are not additional official government SIC levels. The official 4-digit SIC remains the base classification, while Extended SIC provides an additional commercial classification layer.
Explore Extended SIC Code Lookup for the Extended SIC classifications available on SICCODE.com.
Is SIC still current?
The 1987 SIC Manual remains the principal official U.S. SIC reference. NAICS later became the federal statistical standard; SIC continues to be widely used in business data and selected government systems.
Current examples include SEC EDGAR, where SIC classifications remain in use, while OSHA continues to maintain searchable SIC reference tools.
For a detailed review of current government use, see What Government Agencies Still Use SIC Codes?
Primary SIC sources
These government references document the official SIC structure, detailed industries, historical status, and selected current government uses.
- OSHA — Standard Industrial Classification System Search
Searchable 1987 SIC Manual with 2-, 3-, and 4-digit SIC descriptions and manual structure. - U.S. Bureau of Labor Statistics — SIC Industry Titles
Official historical SIC-coded QCEW industry titles and transition context. - U.S. Bureau of Labor Statistics — QCEW Field Definitions
Documents the 1987 SIC hierarchy and its 1,005 detailed 4-digit industries. - U.S. Securities and Exchange Commission — SIC Code List
Current SEC use of SIC classifications in EDGAR and filing-review responsibility.
SIC code questions and answers
How many digits are in an official SIC code?
The detailed official SIC industry level uses 4 digits. The hierarchy also includes broad Divisions, 2-digit Major Groups, and 3-digit Industry Groups.
How many detailed SIC industries are there?
The 1987 SIC system defines 1,005 detailed 4-digit industries.
Is SIC still used today?
Yes. SIC remains widely used today in business-data and commercial classification workflows and continues to appear in selected government systems, including SEC EDGAR.
Who assigns SIC codes?
There is no single central authority assigning one universal SIC code to every business. Government agencies, data providers, financial systems, and other organizations may classify businesses using SIC for their own records and workflows.
What does NEC mean in SIC?
NEC means “Not Elsewhere Classified.” An NEC industry generally covers activities that belong within a broader industry area but are not specifically classified in another listed industry.
Can a business have both a SIC code and a NAICS code?
Yes. SIC and NAICS are separate classification systems, and a business can be classified under both. The codes should not be assumed to be exact one-to-one equivalents.
Are Extended SIC codes official government codes?
No. Official U.S. SIC ends at 4 digits. Extended SIC classifications add proprietary commercial detail below the official SIC industry.