SIC 9621 to NAICS Code Crosswalk
The legacy 1987 SIC code 9621 (Regulation and Administration of Transportation Programs) maps transitively to modern U.S. Census 2022 NAICS code(s): 488111, 926120.
Concordance Concordance Mapping Asset
| Source Code | Source Industry | Target Code | Target Industry | Relation | Concordance Path |
|---|---|---|---|---|---|
| SIC 9621 | Regulation and Administration of Transportation Programs | NAICS 488111 | Air Traffic Control | One-to-Many | SIC1987:9621 → NAICS1997:488111 → 2002:488111 → 2007:488111 → 2012:488111 → 2017:488111 → 2022:488111 |
| SIC 9621 | Regulation and Administration of Transportation Programs | NAICS 926120 | Regulation and Administration of Transportation Programs | One-to-Many | SIC1987:9621 → NAICS1997:92612 → 2002:926120 → 2007:926120 → 2012:926120 → 2017:926120 → 2022:926120 |
Why Concordances Don't Line Up 1:1
The Standard Industrial Classification (SIC) system was established in 1937 and last updated in 1987, organizing businesses by end products. The North American Industry Classification System (NAICS) replaced it in 1997, classifying establishments by production processes. Because of this structural shift, many-to-many relationships are common, requiring chained concordance steps to bridge the historical gap.
Reverse Crosswalk: Going the other way? See the mapping at NAICS 488111 to SIC, NAICS 926120 to SIC.
Related Pages & Tools
- SIC Code 9621 Profile — Legacy OSHA definition and associated industrial metadata.
- SIC Major Group 96 Hub — Legacy category group directory.
- Interactive Crosswalk Engine — Convert any SIC or NAICS code dynamically.
Primary Ingestion Source
Data sourced from the U.S. Census Bureau Concordances (1997, 2002, 2007, 2012, 2017, and 2022 editions). Last verified on 2026-06-30.