Business 

The North American Industry Classification System (NAICS) is the hierarchical, numerical system used by the Federal government to classify businesses in order to collect, analyze, and publish statistical data related to the U.S. business economy.  While it replaces the Standard Industrial Classification (SIC) System, some resources still use the old SIC codes.

Use the official NAICS site to identify the NAICS and/or SIC codes for your topic. 

Note:

• Separate codes exist for manufacturers, retailers, and wholesalers.

• Some resources may include only a company's assigned "primary" industry code.  Primary codes apply to the company's main line of business. "Secondary" codes may appear if a company has multiple lines of business.

Official NAICS website
Print: GEN REF HF 1042.N6 2002

NAICS Association

SIC Manual
Print: GEN REF HF 1042.S731 1986

The North American Product Classification System (NAPCS) was created to gather data on products (goods and services) produced by service industries.

These resources either contain SIC or NAICS indexes or else organize content or permit searching by industry codes or categories.

Resources vary in the specificity of industry categories and sub-categories. Some include only the broader classification.

To determine the industry code assigned to a company, start with a company directory. For industry ratios, consult the ratio guide.

Selected Print Resources:

Ward's Business Directory
General Reference HG 4057.A1W35

Standard & Poor Register of Corporations
General Reference HG 4057.A1S8

Hoover's Handbook of World Business
General Reference HG 4009.H66

Hoover's Master List of Major U.S. Companies
General Reference HG 5035.H66

Market Share Reporter
General Reference HF 5410.M35

Business Rankings Annual
General Reference HG 4050.B88

Manufacturing & Distribution USA
General Reference HD 9721.M364

Service Industries USA
General Reference HD 9981.3.S47

Thomas Register of Manufacturers
General Reference T 12.T6

Electronic Directories:

ReferenceUSA: an online phonebook
Use Guided Search to search by geographic criteria and industry codes or yellow page heading. This is the most comprehensive business directory of U.S. public, private, and nonprofit organizations.

Dun & Bradstreet Million Dollar Database
Basic information on over 1,260,000 U.S. leading public and private businesses with at least $1 million in sales, 20 full-time employees, or 50 employees at a branch.  Geographic criteria and zip code ranges may be specified. 

Mergent Online
Retrieve a list of public companies by primary and/or secondary industry codes through the Advanced Search screen. Primary codes represent the main line of business; secondary codes capture more companies that serve a particular industry.

Hoover's Academic
Public and private business directory of U.S. businesses.

Manufacturing & Distribution USA 4th Edition (2006)
Industry statistics include regional information and lists of leading companies

ThomasNet
Online version of Thomas Register of Manufacturers