Big 4 & National CPA Firms
Global and national accounting firms auditing large public and private companies.
Market snapshot
These figures describe Audit & Assurance (1.1.1), the segment that Big 4 & National CPA Firms sits within — not Big 4 & National CPA Firms on its own.
- Market size
- ~$145B
- Growth
- ~7.0%CAGR (2017–22, nominal)
- Companies
- ~50,885 firms
95.3% of firms have fewer than 20 employees — 48,511 micro-businesses, below most mandates.
- 20–99
- 2,01585%
- 100–499
- 27111%
- 500+
- 884%
Percentages are of the 20+ employee universe. 20–99 and 100–499 are the lower-middle market; 500+ is at scale.
Audit is one service line within these offices — receipts span audit, tax, and advisory.
NAICS 541211. U.S. Census Bureau — 2022 Statistics of U.S. Businesses; U.S. Census Bureau — 2022 Economic Census.
Business model & economics
Revenue model
Engagement fees on recurring annual audit and attestation cycles
Key economics
- Revenue per firm
- $2,844,243
- Revenue per employee
- $243,722
- Employees per firm
- 11.3
- Recurring revenue
- High
- EBITDA margin
- 15–25% (owner-comp adjusted)
- Capex intensity
- Low
annual audits renew with high switching costs
Characteristics
- Balanced cost base — payroll is 37% of revenue, leaving room to scale margin without cutting staff
- Moderate strategic-buyer pool — 88 firms exceed 500 employees; a scaled asset has buyers, but not many
- Independence rules constrain cross-selling and shape how PE can own audit firms.
- Annual recurrence and regulatory necessity make revenue durable and predictable.
- Talent scarcity — the CPA pipeline — is the binding capacity constraint.
NAICS 541211. U.S. Census Bureau — 2022 Statistics of U.S. Businesses; U.S. Census Bureau — 2022 Economic Census.
M&A deal context
Who’s acquiring
- PE-backed platforms (alternative practice structures)
- National & super-regional CPA firms
- Consolidating regional firms
What’s driving deals
- Independence rules pushing deals into alternative practice structures that separate attest from advisory.
- Aging partners and succession gaps driving sales of independent firms.
- Buyers chasing capacity and talent more than the audit margin itself.
Find Big 4 & National CPA Firms acquisition targets
Search Acquisera’s index for companies classified under Big 4 & National CPA Firms (1.1.1.1) and build a targeted deal pipeline.
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