SIC Classification & Reference Center
This reference center organizes SICCODE.com’s SIC governance materials—methodology, versioning, accuracy benchmarks, and review standards—so teams can document and maintain SIC assignments consistently across datasets and time.
Designed for advanced and professional users who need consistent SIC assignment, boundary interpretation, and governance context (audit-ready decision logic).
This page covers: SIC methodology, governance, accuracy guidance, and how to apply SIC consistently across teams and time.
This page does not cover: the SIC definition or keyword lookup. For the definition, use “What Is a SIC Code?” For finding codes, use the SIC directory.
Choose the path that matches your intent:
Public access & services boundary: SICCODE.com maintains free public access to core SIC and NAICS classification reference materials; paid services support organizations that require formal verification, documentation, enterprise-scale classification, or application of classification data to internal business records.
If you still see SIC in portals or archives, use this documented reference to understand where and why it persists: What Government Agencies Still Use SIC Codes?
Authority & governance signals
On this page
SIC foundations
Definitions & context (basic)
Keep definition intent separate from this reference center. Use these when you need the basics or historical framing.
Structure & taxonomy
Understand SIC’s numeric taxonomy and how SIC codes relate to hierarchy and segmentation layers.
SIC assignment governance checklist
Purpose: establish a consistent, auditable SIC assignment standard across datasets and time.
Governance checklist:
- Record the unit of classification (establishment/location vs company).
- Store the decision proxy used (revenue preferred; otherwise payroll/hours/headcount).
- Require a boundary check (including/excluded) before finalizing.
Method References:
Governance, methodology, and accuracy
These pages explain how SIC classifications are interpreted, validated, and controlled to support consistent use across teams, datasets, and time horizons.
SIC classification methodology
How SICCODE.com resolves SIC assignment decisions using explainable interpretation and review.
SIC governance & versioning
How SIC stability, changes, and classification drift are managed for longitudinal reporting and legacy systems.
SIC accuracy benchmarks
Benchmarks and validation checks to assess fit, hierarchy alignment, and stability across records.
How SIC codes are used
Common use cases
SIC supports historical analysis, legacy reporting systems, crosswalks to NAICS, and business intelligence workflows like segmentation and benchmarking.
Tools & conversions
After verifying the SIC code on the code page, use conversion tools and downstream workflows for analysis and targeting.
Who uses SIC today?
SIC remains widely used when organizations need consistent historical classification for time-series reporting, legacy systems, and cross-dataset comparability. Many workflows use SIC directly or alongside NAICS.
Common SIC users
- Financial services: legacy portfolio analysis, risk segmentation, and historical benchmarking.
- Insurance: long-run claims history and category-level underwriting comparisons.
- Government & research: archived reporting, longitudinal studies, and historical economic datasets.
- Marketing & analytics teams: segmentation, targeting, TAM analysis, and trend comparisons across time.
- Data engineering: mapping SIC fields to NAICS while preserving lineage and comparability.
Why SIC is still referenced
- Continuity: stable taxonomy for older records and long time horizons.
- Comparability: supports crosswalks and reconciliations between SIC and NAICS.
- System compatibility: many CRM/ERP/reporting stacks still store SIC fields.
- Documented persistence: some government systems and archives still reference SIC fields even when NAICS is primary.
Reference: What Government Agencies Still Use SIC Codes?
SIC directory access
When you are ready to find or validate a code, use the directory to browse or search and then open the specific SIC code page for included/excluded activities, examples, and related context.
Lookup intent: browse and search all SIC sectors and codes (directory).
Questions & answers
- What is the difference between SIC and NAICS?
SIC is a legacy U.S. industry classification system used widely for historical comparability and long-running datasets. NAICS is the modern standard used for current statistical reporting. Many organizations maintain both to align modern reporting with historical records. - Can I use SIC codes for modern compliance workflows?
Sometimes, but typically alongside NAICS. Use SIC for legacy datasets and archival comparability; use NAICS when a current program, filing, or agency requires it. - How do I find a SIC code?
Use the SIC directory to search or browse, then open the specific SIC code page to verify scope (included/excluded activities and examples). If unsure, follow the selection framework. - Are SIC codes still maintained?
The official SIC system changes slowly. Most organizations keep SIC stable to preserve historical comparability and use governance guidance to apply SIC consistently across records and teams.
Need help applying SIC defensibly? See SIC Classification Methodology and SIC Governance & Versioning.