SIC Classification & Reference Center
SIC (Standard Industrial Classification) is a legacy industry coding system still used to classify businesses for historical reporting, analytics, segmentation, and cross-dataset comparability. SIC codes remain a foundational taxonomy for longitudinal datasets, legacy reporting systems, and many compliance workflows.
This reference center organizes SICCODE.com’s SIC materials—definitions, structure, governance, methodology, accuracy guidance, and directory access—so users can apply SIC codes consistently, defensibly, and with full context.
Public access & services boundary: SICCODE.com has always maintained 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.
Use this hub to learn SIC fundamentals, then browse the directory to open a specific SIC code page for included/excluded activities, examples, and contextual guidance.
Open SIC Code Lookup / Directory or review SIC vs NAICS.
If you still see SIC in government 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
Start with SIC lookup
If you already have a SIC keyword or code, use the directory to search and then open the specific code page for included/excluded activities, examples, and historical context. If you are unsure which code fits a business, use the selection framework first.
SIC foundations
What SIC is
Definitions, context, and why SIC still matters in long-standing datasets.
How SIC is structured
Understand SIC’s numeric taxonomy and how codes are arranged hierarchically.
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 evidence-based interpretation and expert review.
SIC governance & versioning
How updates are managed and how classification drift is prevented for legacy systems and longitudinal reporting.
SIC accuracy benchmarks
Benchmarks and validation checks to assess SIC fit, hierarchy alignment, and stability.
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 identifying the correct SIC code, 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 engineers & architects: mapping legacy SIC fields to modern NAICS fields in data warehouses (e.g., Snowflake) and operational systems (e.g., CRM/ERP) 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?
Browse SIC codes
Start at the SIC directory and drill down from major groups to the specific industry code page for definition, scope notes, and examples.
Directory access: browse and search all SIC sectors and codes.
Questions & answers
- What is the difference between SIC and NAICS?
SIC is a legacy U.S. industry classification system that remains important for historical comparability. NAICS is the modern standard used for current statistical reporting. Many organizations maintain both so modern reporting aligns with historical records and cross-dataset continuity. - Can I use SIC codes for modern compliance workflows?
Often yes, but typically alongside NAICS. Use SIC for legacy datasets, archived program comparability, and long time horizons; use NAICS for modern standards-based reporting when required by an agency, program, or filing. - How do I find a SIC code?
Use the SIC directory to search by keyword, then open the specific SIC code page to verify included/excluded activities and examples. If you are unsure, follow the code selection framework. - Are SIC codes still maintained?
The official SIC system changes slowly. Organizations typically keep SIC stable to preserve historical comparability and use governance guidance to apply SIC consistently across teams and time.
Need help applying SIC defensibly? See the SIC Classification Methodology and SIC Governance & Versioning.