SIC Classification & Reference Center

Updated: 2025
Category: SIC Classification & Reference Center
Reviewed By: SICCODE.com Industry Classification Review Team (classification research, data governance, and standards alignment)

SIC (Standard Industrial Classification) is a legacy industry coding system still used to classify businesses for historical reporting, analytics, marketing 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.

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.

Next step

Open SIC Code Lookup / Directory or review SIC vs NAICS.

Authority & governance signals
Hub: SIC Classification & Reference Center
Methodology: SIC Classification Methodology
Governance: SIC Governance & Versioning
Accuracy: SIC Accuracy Benchmarks

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.

Open SIC Code Lookup / Directory SIC vs NAICS (reference) How to Choose the Correct SIC Code

SIC foundations

What SIC is:

Definitions, governing bodies, and why the SIC system exists and matters in long-standing datasets.

Reference intent Historical context

How SIC is structured:

Understand SIC’s numeric taxonomy and how codes are arranged historically and hierarchically.

Hierarchy Legacy usage

Governance, methodology, and accuracy

These pages explain how SIC classifications are interpreted, validated, versioned (as relevant for legacy data), and maintained to reduce drift and support consistent use.

SIC classification methodology

How SICCODE.com resolves SIC assignment decisions using evidence-based interpretation and expert review.

Explainable Audit-ready

SIC governance & versioning

How updates are managed, change cycles are handled, and classification drift is prevented for legacy data.

Lifecycle Controls

SIC accuracy benchmarks

Practical benchmarks and validation checks to assess SIC fit, hierarchy alignment, and stability.

Quality Consistency

How SIC codes are used

Common use cases

SIC codes support historical analysis, legacy reporting systems, compliance workflows, crosswalks to NAICS, and business intelligence use cases like segmentation and benchmarking.

Context Legacy comparison

Tools & conversions

After identifying the correct SIC code, these tools help with intelligence workflows and code translation.

Tooling Conversion

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: longitudinal studies, archived reporting, and historical economic datasets.
  • Marketing & analytics teams: segmentation, targeting, TAM analysis, and trend comparisons across time.
Legacy datasets Analytics Segmentation

Why SIC is still referenced

  • Continuity: stable legacy 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.
  • Procurement & compliance overlap: some workflows reference SIC even when NAICS is primary.

Next step: Browse the SIC directory or compare SIC vs NAICS.

Continuity Crosswalks Compatibility

Browse SIC codes

For sector-based browsing, start at the SIC directory and drill down from sector to the specific industry code page.

Directory access: browse and search all SIC sectors and codes.

Browse SIC Codes SIC to NAICS Conversion

Questions & answers

  • What is the difference between SIC and NAICS?
    SIC is a legacy classification system that NAICS replaced for modern statistical reporting; however, SIC remains important for historical data and crosswalks.
  • Can I use SIC codes for modern compliance workflows?
    Yes, but often in conjunction with NAICS. Use SIC for historical datasets and NAICS for current federal reporting standards.
  • How do I find a SIC code?
    Use the SIC directory search above and review included/excluded activities and examples on the specific SIC code page. If you are unsure which code fits, follow the code selection framework.
  • Are SIC codes still maintained?
    SIC definitions evolve slowly; governance guidance helps maintain consistency for legacy reporting and comparison across time.