Industry classification guide
What Is a SIC Code?
A Standard Industrial Classification code identifies a type of business activity within the older U.S. SIC system. The detailed industry code is four digits. Although NAICS replaced SIC as the federal statistical standard, some forms, databases, and business workflows still ask for a SIC code.
The short answer
SIC groups establishments by their primary activity
The 1987 Standard Industrial Classification Manual organizes economic activity from broad divisions down to four-digit industries. A code describes the activity assigned under that classification system; it is not a license, approval, certification, or statement that a business can accept a particular payment method.
Code structure
Read the SIC hierarchy from broad to specific
Division
A letter represents a broad economic division, such as manufacturing, retail trade, or services.
Major group
The first two digits narrow the activity to a major group within the division.
Industry group
Three digits identify a more specific industry group.
Industry
The complete four-digit code identifies the detailed industry described by the manual.
Verification path
How to find a defensible SIC code
Start with what the establishment primarily does, then compare the official descriptions rather than choosing from a label alone.
1. Describe the primary activity
Write down the main product produced, merchandise sold, or service delivered by the establishment. Avoid relying only on the company name.
2. Search the official manual
OSHA provides access to the 1987 SIC manual and a search by keyword or code. Review the hierarchy and the detailed industry description.
3. Compare nearby categories
Read the scope of plausible codes and any included or excluded activities. A broad keyword match may not capture the establishment's primary activity.
4. Confirm the requester's rule
If a processor, insurer, lender, regulator, or data vendor asks for a code, confirm which classification it uses and how it assigns businesses with multiple activities.
SIC and NAICS
Do not treat the two systems as interchangeable
The Census Bureau states that NAICS replaced SIC as the federal standard in 1997. NAICS remains the current federal industry classification for statistical purposes, while legacy data and some private or administrative workflows may continue to use SIC.
SIC
- Older U.S. classification system
- Detailed industries use four digits
- The searchable official manual is the 1987 edition
- Still appears in some legacy and private-sector workflows
NAICS
- Replaced SIC as the federal statistical standard
- Developed for comparable North American statistics
- Uses a different structure and more detailed codes
- Is updated on a recurring cycle
Payment context
Why a payment application may ask about industry
Payment providers commonly collect a description of business activity during onboarding and account maintenance. The requested field may be labeled SIC, NAICS, industry, business type, or another provider-specific classification. Answer with an accurate description and follow the provider's instructions; Payments Max does not assign codes for unrelated organizations.
Use current operations
Describe what the business actually sells or does now. Update the provider if the primary activity materially changes.
Separate establishments when required
A company may operate more than one establishment or activity. The requesting organization may have rules for selecting the primary one.
Avoid unsupported conclusions
A classification code alone does not determine pricing, approval, funding timing, legality, compliance, or payment-method compatibility.
Related resources
Continue your merchant account research
Common questions
SIC code FAQ
How many digits are in a SIC code?
A detailed SIC industry code has four digits. The manual also groups industries at broader two- and three-digit levels.
Is SIC the same as NAICS?
No. NAICS replaced SIC as the federal statistical standard and uses a different structure. Follow the specific field requested.
Where can I look up a SIC code?
OSHA hosts a searchable version of the 1987 SIC manual with keyword, code, hierarchy, and detailed-description views.
Does a SIC code decide merchant account approval?
No single classification code guarantees or prevents approval. Providers evaluate applications under their own current requirements and risk processes.
Last editorial review: August 12, 2026. Reviewed against the official OSHA SIC manual and current U.S. Census Bureau classification guidance.
Next step
Verify the activity before submitting the code
Compare the establishment's primary activity with the official manual, then confirm whether the requesting organization wants SIC, NAICS, or its own industry classification.
To learn more about how TSYS can help improve the way your organization accepts payments, markets to new customers, or manages its HR responsibilities, get in touch by calling 585-981-8463 to get started.
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