Decades of Historical Financial Modeling
Commercial credit registries (such as Dun & Bradstreet) and insurance carrier tables continue to use SIC codes because their predictive algorithms were built on decades of historical data structured around the 4-digit system [1]. Re-indexing millions of records is costly and complex.
Furthermore, because the 4-digit SIC system is simpler than the 6-digit NAICS, many sales and B2B lead generation tools rely on SIC codes to segment target accounts. Regulatory bodies like the Securities and Exchange Commission (SEC) and OSHA also retain SIC filters to maintain continuity in their search systems [2][3].