From the SBA:
“To qualify as a small business concern for most SBA programs, small business size standards define the maximum size that a firm, including all of its affiliates, may be. A size standard is usually stated in number of employees or average annual receipts. SBA has established two widely used size standards—500 employees for most manufacturing and mining industries, and $7 million in average annual receipts for most nonmanufacturing industries. While there are many exceptions, these are the primary size standards by industry. (For more complete information on size standards, see SBA’s Small Business Size Regulations (13 CFR §121) or the Table of Small Business Size Standards.
Construction
* General building and heavy construction contractors: $33.5 million
* Special trade construction contractors: $14 million
* Land subdivision: $7 million
* Dredging: $20 million
Manufacturing
* About 75 percent of the manufacturing industries: 500 employees
* A small number of industries: 1,500 employees
* The balance: either 750 or 1,000 employees
Mining
* All mining industries, except mining services: 500 employees
Retail Trade
* Most retail trade industries: $7 million
* A few (such as grocery stores, department stores, motor vehicle dealers and electrical appliance dealers), have higher size standards, but none above $35.5 million.
Services
* Most common: $7 million
* Computer programming, data processing and systems design: $25 million
* Engineering and architectural services and a few other industries have different size standards.
* The highest annual-receipts size standard in any service industry: $35.5 million
* Research and development and environmental remediation services: the only service industries with size standards stated in number of employees
Wholesale Trade
* For small business Federal contracts: 100 employees, and the firm must deliver the product of a small domestic manufacturer, as set forth in SBA’s nonmanufacturer rule, unless waived by the SBA for a particular class of product. For procurements made under the Simplified Acquisition Procedures of the FAR and where the purchase does not exceed $25,000, the nonmanufacturer may deliver the goods of any domestic manufacturer.
* For loans and all other programs: 100 employees is applicable for all industries.
Other Industries
* Divisions include agriculture; transportation, communications, electric, gas, and sanitary services; and finance, insurance and real estate.
* Because of wide variation in the structure of industries in these divisions, there is no common pattern of size standards.”