IRS PBA Definition
Principal Business Activity code. A six-digit classification code used on IRS tax returns, derived from NAICS codes to categorize primary business revenues.
Related Guides & Tools
- SBA Size Standards Guide — Legal rules of small business classification.
- Federal Contracting Identifiers Guide — Overview of CAGE, DUNS, and Unique Entity IDs.
- SIC ↔ NAICS Concordance Crosswalk — Search and map old SIC codes to modern formats.