Standard Industrial Classification (SIC) Code

What is a SIC code?

A Standard Industrial Classification (SIC) code is a four-digit numerical code used to categorize U.S. companies by their primary business activity. Introduced in 1937, SIC codes were developed to classify and analyze economic activity across industries and government agencies.

Although the North American Industry Classification System (NAICS) largely replaced SIC in 1997, many federal agencies—including the Securities and Exchange Commission (SEC)—and private organizations still use SIC codes. The U.S. government stopped updating the official SIC list in 1987; private groups have since produced expanded and more detailed versions.

How SIC compares to NAICS

• SIC: Four-digit codes, long history, widely used in legacy systems and some government workflows. Over time private updates have produced many more granular classifications.
• NAICS: Six-digit codes introduced to standardize data collection across the U.S., Canada, and Mexico. Intended to replace SIC but has not fully supplanted it.
• Many companies now have both a SIC and a NAICS code; crosswalks exist to map between the systems.

Structure and how to read a SIC code

SIC codes are hierarchical:
– First two digits: major industry group (fit into one of 11 broad divisions).
– Third digit: industry group (narrows the classification).
– Fourth digit: specific industry (most specific category).

Example:
– 35—Industrial and Commercial Machinery and Computer Equipment
– 357—Computer and Office Equipment
– 3571—Electronic computers

The 11 major SIC divisions

1. Agriculture, forestry, and fishing
2. Mining
3. Construction
4. Manufacturing
5. Transportation and public utilities
6. Wholesale trade
7. Retail trade
8. Finance, insurance, real estate
9. Services
10. Public administration
11. Nonclassifiable establishments

These divide into 83 two-digit groups, about 416 three-digit groups, and more than 1,000 four-digit industries (with private expansions yielding even more granular codes).

Practical applications

Businesses and government use SIC codes for many purposes:

For businesses
– Identify customers, prospects, and competitors by industry
– Target marketing campaigns
– Classify entities for taxation and regulatory filings
– Help lenders assess industry risk
– Locate government contracting opportunities

For government and researchers
– Standardize and organize economic data across agencies
– Sort and review company filings (e.g., SEC/EDGAR)
– Support statistical analysis and policy research

Finding your SIC code

Simple ways to locate the appropriate SIC code:
– Search by keywords using the U.S. Department of Labor’s online SIC search tool.
– Use NAICS-to-SIC crosswalks if you know your NAICS code.
– Check a company’s SEC/EDGAR filings to see the SIC listed.
– Refer to published SIC code lists (e.g., SEC or Department of Labor PDFs).

Real-world examples

• Apple Inc.: SIC 3571 (electronic computers).
• Bank of America: SIC 6021 (national commercial banks). State banks: 6022.
• Bakery products: 2050; cookie & cracker manufacturers: 2052.
• Real estate: 6500 (real estate industry); 6510 (real estate operators); 6512 (nonresidential buildings); 6513 (operators of apartment buildings).

Who needs a SIC code?

Every business can be classified by a SIC code. Public companies use SIC codes when filing reports with government agencies like the SEC. Regulators, analysts, lenders, marketers, and researchers commonly rely on SIC codes for sorting and comparing companies by industry.

Conclusion

SIC codes remain an important industry-classification tool despite the adoption of NAICS. They provide a concise, hierarchical system for categorizing business activity and are still used across government, financial, and commercial workflows. To identify a company’s SIC code, use government search tools, SEC filings, or NAICS crosswalks.

Sources

• Office of Statistical Standards — History of the Standard Industrial Classification
• U.S. Census Bureau — North American Industry Classification System
• U.S. Securities and Exchange Commission — Division of Corporation Finance: SIC Code List
• U.S. Department of Labor — SIC System Search
• NAICS Association — NAICS & SIC crosswalks