NAICS vs SIC Code: Key Differences Explained (2026 Guide)
SIC codes and NAICS codes both classify businesses by industry, but they serve different regulatory contexts, have different structures, and have different vintage. This guide explains when to use each system, how to convert between them, and how to find both codes for any business.
What Is a SIC Code?
A Standard Industrial Classification (SIC) code is a 4-digit number that the U.S. government has used since the 1930s to classify businesses by their primary economic activity. SIC codes were developed cooperatively among government statistical agencies and were last comprehensively revised in 1987. Despite their age, SIC codes remain the primary industry classification system used by the Securities and Exchange Commission in EDGAR filings, by OSHA for workplace safety statistics, and for various IRS tax reporting purposes.
The SIC system organizes all economic activity into a hierarchical structure. At the top are 11 major divisions (A through J), each covering a broad economic sector: Agriculture, Mining, Construction, Manufacturing, Transportation, Wholesale Trade, Retail Trade, Finance/Insurance/Real Estate, Services, and Public Administration. Within each division, major groups (2-digit codes) provide more specific categorization, and individual industries (4-digit codes) provide the most specific classification.
There are approximately 1,004 active SIC codes covering the complete range of U.S. business activities. Every public company filing with the SEC has a SIC code assigned based on the primary business activity described in their registration statement. Use our free SIC Code Lookup tool to find the SIC code for any industry.
What Is a NAICS Code?
The North American Industry Classification System (NAICS) was introduced in 1997 to replace SIC codes as the primary classification system for U.S., Canadian, and Mexican federal statistical agencies. Developed jointly by the U.S. Census Bureau, Statistics Canada, and Mexico's INEGI, NAICS was designed to provide a more modern classification framework that better reflects the structure of the late 20th century economy — particularly the growth of the service sector and technology industries that SIC codes, designed in the 1930s, handle poorly.
NAICS codes are 6 digits, providing more granular industry classification than the 4-digit SIC system. The structure is hierarchical: the first 2 digits identify the sector, the third digit the subsector, the fourth digit the industry group, the fifth digit the NAICS industry, and the sixth digit (where applicable) the national industry — a country-specific subdivision used by the U.S. Census when U.S. industry structure differs from the NAICS standard.
NAICS is updated every 5 years (2017, 2022, 2027 cycles) to reflect changes in industry structure and economic activity. The 2022 NAICS revision introduced significant updates to digital economy, healthcare, and technology sector classifications. This regular revision process ensures NAICS remains current in a way that the static SIC system cannot.
Key Structural Differences
The most immediately visible difference between SIC and NAICS is the code length: 4 digits vs. 6 digits. The additional digits in NAICS enable substantially more granular classification. Where SIC has one code for "Computer Programming, Data Processing" (7371), NAICS has over a dozen distinct codes for software development, computer systems design, data processing, cloud computing, and related activities.
The organizational principles also differ. SIC codes are organized primarily around what is produced (manufacturing SIC codes, for example, are organized by product type). NAICS is organized around production processes — how goods or services are produced — which better aligns with how modern businesses are actually structured. A company producing similar goods through very different processes would be classified differently under NAICS but might share a SIC code.
The treatment of service industries differs significantly. SIC's Division I (Services) is a broad catch-all that covers everything from hotels to computer programming to health care. NAICS breaks service industries into multiple separate sectors with much greater specificity. This is one of the primary reasons NAICS was developed — the SIC system's handling of service industries was increasingly inadequate as services grew to dominate the U.S. economy.
When to Use SIC Codes
Use SIC codes when working with: SEC EDGAR filings and financial regulatory data (the SEC uses SIC, not NAICS), OSHA industry statistics and workplace safety data, IRS business classification for certain tax forms and regulatory purposes, older government datasets that predate NAICS adoption, and legal and regulatory contexts that specifically reference SIC codes.
The SEC's EDGAR system classifies every registered company with a SIC code. When building financial applications using the EDGAR API, SIC codes are the industry classification in the submissions data (the sic field in company submissions JSON). Filtering EDGAR data by industry or comparing across companies within a sector requires using SIC codes for consistency with the EDGAR classification system.
SIC code 7372 (Prepackaged Software) is the most common SIC code in EDGAR, reflecting the large number of technology companies registered with the SEC. Other technology-heavy SIC codes include 7371 (Computer Programming), 3674 (Semiconductors), 3661 (Telephone Equipment), and 3663 (Radio & TV Communications Equipment).
When to Use NAICS Codes
Use NAICS codes when working with: U.S. Census Bureau economic data (the Census exclusively uses NAICS), Bureau of Labor Statistics employment and wage data, Small Business Administration size standards (SBA small business eligibility is defined by NAICS code), federal procurement and contracting (government contracts use NAICS for classifying contracts), recent academic economic research that uses Census or BLS data, and any economic analysis published after approximately 2000 that uses federal statistical data.
When applying for SBA loans, government grants, or federal contracts, you will need your NAICS code rather than your SIC code. The SBA publishes size standards for each NAICS code — the maximum annual receipts or number of employees that qualifies a business as "small" for federal program purposes. These thresholds vary significantly by industry.
The Census Bureau's American Community Survey, Economic Census, County Business Patterns, and most other Census products use NAICS. If you are analyzing industry data from Census or BLS sources, you must use NAICS codes. Mixing SIC and NAICS data in the same analysis will produce incorrect results since the two systems classify many industries differently.
How to Convert Between SIC and NAICS
There is no perfect one-to-one mapping between SIC and NAICS codes because the two systems use different organizational principles and different levels of granularity. The Census Bureau publishes official concordance tables — mappings between the two systems — but these tables frequently show one SIC code mapping to multiple NAICS codes (one-to-many) or multiple SIC codes mapping to one NAICS code (many-to-one).
The official concordance tables are available from the Census Bureau at https://www.census.gov/eos/www/naics/ under the "Concordances" section. The tables show, for each SIC code, the NAICS codes to which businesses in that SIC might be classified, with notes about the nature of the overlap. These concordances are useful for approximate industry mapping but should not be treated as exact equivalences.
For practical research purposes, the most reliable approach is to look up the specific industry in both the SIC and NAICS systems independently, verify the classification matches the business activity in question, and note the mapping for that specific case. Automated SIC-to-NAICS conversion at scale requires accepting the ambiguity inherent in the concordance tables. Our SIC code entries include the primary NAICS equivalent as a reference point.
Finding SIC Codes for SEC Filings
Every SEC-registered company has a SIC code on file in EDGAR. You can find a company's SIC code using our Company Search tool — the SIC code appears in the company's registration information. Alternatively, look at the cover page of the company's most recent 10-K annual report, where the SIC code is listed in the header information alongside the company name and state of incorporation.
The SEC's EDGAR full-text search (accessible through our Full-Text Search tool) allows you to filter results by SIC code — useful for finding all SEC filers in a specific industry. The EDGAR company search on SEC.gov also supports industry-based filtering by SIC code.
For programmatic access to SIC codes across all EDGAR registrants, the company_tickers.json file and the EDGAR submissions API both include the SIC code field for each registrant. This enables building databases of publicly traded companies organized by industry for quantitative research or competitive analysis.
NAICS and SIC in Financial Research
When doing cross-company financial analysis or industry peer benchmarking using SEC EDGAR data, you will need to work with SIC codes — that is the classification system in EDGAR. However, when supplementing financial data with economic statistics (employment trends, industry revenue data, regional economic data) from Census Bureau or BLS sources, you will need NAICS codes.
This creates a translation challenge for analysts combining financial and economic data sources. The practical solution is to maintain both SIC and NAICS classifications for each company in your dataset, and use the appropriate system depending on the data source. Use SIC when querying EDGAR; use NAICS when querying Census or BLS data; and be cautious about comparing across the two systems without explicitly handling the mapping ambiguities.
Industry ETFs and sector indices typically use their own proprietary classification systems (GICS — Global Industry Classification Standard, or ICB — Industry Classification Benchmark) that differ from both SIC and NAICS. For research combining ETF holdings, index composition, and SEC EDGAR data, you may need to maintain mappings across three or four different classification systems.
Frequently Asked Questions
What is the difference between SIC and NAICS codes?
SIC codes are 4-digit codes last revised in 1987, used by the SEC, IRS, and OSHA. NAICS codes are 6-digit codes introduced in 1997 for U.S., Canadian, and Mexican statistical agencies. The SEC uses SIC; the Census Bureau and BLS use NAICS.
Which code does SEC EDGAR use?
SEC EDGAR uses SIC codes. Every company registered with the SEC has a 4-digit SIC code on file. Use our SIC Code Lookup tool to find any industry's SIC code.
Are SIC codes still relevant in 2026?
Yes. Despite NAICS largely replacing SIC for federal statistical purposes, SIC codes remain the standard for SEC filings, OSHA data, and certain IRS reporting. Any work with EDGAR financial data requires using SIC codes.
How many SIC codes are there?
There are approximately 1,004 active SIC codes organized into 11 major divisions. Use our SIC Code List page to browse all codes or our SIC Code Lookup tool to search by industry name or code number.
What is the SIC code for technology companies?
Common technology SIC codes include: 7372 (Prepackaged Software), 7371 (Computer Programming), 3674 (Semiconductors), 3661 (Telephone Equipment), 3663 (Radio & TV Communications Equipment), and 3577 (Computer Peripheral Equipment).
How do I convert a SIC code to NAICS?
The Census Bureau publishes official SIC-to-NAICS concordance tables at census.gov/naics. Note that the mapping is often one-to-many — one SIC code may correspond to multiple NAICS codes depending on the specific business activity.