Professional, Scientific, & Technical Services

NAICS 541 covers firms that sell expertise — lawyers, accountants, engineers, architects, management consultants, IT services providers, advertising agencies, and R&D labs. The subsector is the largest private-sector employer of college-educated professionals in the US, generating over $2.4 trillion in revenue according to Census Bureau Service Annual Survey data. Deloitte, PwC, McKinsey, Accenture, AECOM, and Jacobs Engineering are among the best-known firms, but the subsector is dominated numerically by small practices: over 90% of establishments have fewer than 20 employees per Census data.

Geographic concentration tracks metro-area knowledge economies. The Washington DC metro area leads in government-adjacent consulting and defense engineering (Booz Allen Hamilton, Leidos). New York dominates legal and financial advisory. Houston and the Texas Triangle are hubs for petroleum engineering and energy consulting. The San Francisco Bay Area and Boston-Cambridge corridor concentrate life-sciences R&D and tech consulting.

Regulatory and licensing frameworks vary by profession. State bar associations govern law practice; state boards of accountancy enforce CPA requirements under the Uniform Accountancy Act; and state professional-engineering boards license PEs under statutes modeled on NCEES guidelines. The FTC's 2023 proposed ban on non-compete agreements — currently stayed by federal court — would disproportionately affect professional-services firms that rely on non-competes to protect client relationships and proprietary methodologies. SOX compliance, ITAR export controls, and HIPAA obligations create additional regulatory layers for firms serving financial, defense, and healthcare clients respectively.