Short answer
The Big 4 accounting firms are Deloitte, PwC, EY and KPMG. In their latest reported fiscal years, Deloitte had US$74.5 billion of global revenue and nearly 500,000 people (year to May 2026), PwC US$60.2 billion and 369,945 people (June 2026), EY US$57.0 billion and 415,182 people (June 2026), and KPMG US$39.8 billion and 276,030 people (September 2025). Each is a network of legally separate member firms.
- Together the four reported about US$231.5 billion of revenue and roughly 1.56 million people in their latest years.
- Consulting or advisory is the largest business at Deloitte and PwC; at EY, assurance is the largest single line.
- Fiscal years end in May (Deloitte), June (PwC, EY) and September (KPMG), which sets when budgets are decided.
- If one of them audits your company, SEC rules limit it to buying from you as an ordinary-course consumer.
- Deloitte publishes a US figure: US$35.7 billion of US revenue in the year to May 2025.
On this page
This guide is for companies that sell to the Big 4 (technology, data, AI, security, recruiting, training and workplace suppliers), companies that want one as an alliance partner, and anyone who needs their current numbers. Every figure comes from the firm's own annual results release or report, opened on 30 October 2026, and each table states its fiscal year. The firms close their years in different months, so KPMG's latest figures are a year older than the others'. For the thousands of firms below the Big 4, see the list of accounting firms.
The Big 4 at a glance
| Firm | Fiscal year ended | Global revenue | Growth, local currency | People | Countries and territories | Revenue per person (our calculation) |
|---|---|---|---|---|---|---|
| Deloitte | 31 May 2026 | US$74.5 billion | 3.8% | Nearly 500,000 | More than 150 | About US$149,000 (on 500,000) |
| PwC | 30 June 2026 | US$60.2 billion | 3.5% | 369,945 | 136 | About US$162,800 |
| EY | June 2026 | US$57.0 billion | 4.7% | 415,182 | More than 150 | About US$137,200 |
| KPMG | 30 September 2025 | US$39.8 billion | 5.1% | 276,030 | 138 | About US$144,200 |
Revenue per person is revenue divided by headcount at year end: for PwC, US$60,226 million / 369,945 = about US$162,800. Deloitte reports "nearly 500,000 people" for fiscal 2026, so its figure is approximate; its exact count for fiscal 2025 was 473,050. KPMG published its fiscal 2025 results on 16 December 2025; its fiscal 2026 results (to 30 September 2026) weren't out on 30 October 2026. Adding the four: 74.5 + 60.2 + 57.0 + 39.8 = US$231.5 billion, and roughly 1.56 million people.
What each firm sells: revenue by line of service
Each network reports its business lines differently. These are the latest years with dollar figures.
| Firm and year | Line of service | Revenue | Share of firm total (our calculation) |
|---|---|---|---|
| Deloitte, FY2025 | Technology & Transformation | US$33.4 billion | 47% |
| Deloitte, FY2025 | Audit & Assurance | US$14.7 billion | 21% |
| Deloitte, FY2025 | Tax & Legal | US$12.2 billion | 17% |
| Deloitte, FY2025 | Strategy, Risk & Transactions | US$10.3 billion | 15% |
| PwC, FY2026 | Advisory | US$25.8 billion | 43% |
| PwC, FY2026 | Assurance | US$20.5 billion | 34% |
| PwC, FY2026 | Tax and Legal Services | US$13.9 billion | 23% |
| EY, FY2026 | Assurance | US$18.9 billion | 33% |
| EY, FY2026 | Consulting | US$17.4 billion | 31% |
| EY, FY2026 | Tax | US$13.8 billion | 24% |
| EY, FY2026 | EY-Parthenon (strategy and transactions) | US$6.8 billion | 12% |
Deloitte's fiscal 2026 release gives growth by business but not dollar amounts: Tax & Legal grew 5.8%, Audit & Assurance 5%, Strategy, Risk & Transactions 4.4% and Technology & Transformation 2.5% in local currency. KPMG publishes no dollar split; for fiscal 2025 it reported Tax & Legal up 7.5%, Audit up 6.0% and Advisory up 2.9%. By headcount, 37% of PwC people work in Advisory, 33% in Assurance and 16% in Tax and Legal.
The pattern for sellers: tax and legal grew fastest at Deloitte, PwC and KPMG, while Deloitte's largest business, Technology & Transformation, grew slowest (2.5%). All four sell audit and assurance, tax, consulting and deal advisory; only the mix differs.
US and Americas figures
The networks report globally, and the US member firms publish little on their own. Of the four, only Deloitte publishes a US revenue figure on its US site that we found.
| Firm | US or Americas figure | Year |
|---|---|---|
| Deloitte | US$35.7 billion of US revenue (Deloitte LLP and subsidiaries) | Year to 31 May 2025 |
| Deloitte | US$38.8 billion Americas revenue; 223,983 Americas people | Year to 31 May 2025 |
| PwC | US$26.8 billion Americas revenue, up 4.6%, with "particularly strong" growth in the US and Brazil; 22% of PwC people work in the Americas | Year to 30 June 2026 |
| EY | US$25.9 billion Americas revenue, up 4.2%; 87,546 Americas people, down 4.9% | Year to June 2026 |
| KPMG | Americas revenue up 5.6%; no dollar figure | Year to 30 September 2025 |
The Americas includes Canada and Latin America as well as the US. In the US, Deloitte's audit firm, Deloitte & Touche LLP, is licensed to practice public accountancy in 51 states and US jurisdictions, and Deloitte LLP is a Delaware limited liability partnership owned by its partners and principals.
How the networks are structured
Each Big 4 brand is a network. A coordinating company, which doesn't serve clients, sits above legally separate member firms in each country:
- Deloitte: Deloitte Touche Tohmatsu Limited, a UK private company limited by guarantee.
- PwC: PricewaterhouseCoopers International Limited and its member firms.
- EY: Ernst & Young Global Limited, a UK company limited by guarantee.
- KPMG: KPMG International Limited, a private English company limited by guarantee. KPMG states that no member firm has authority to bind KPMG International or any other member firm.
For a seller, this means a contract with the US firm doesn't cover the UK firm, and a global framework agreement still needs each member firm to sign up. Network-wide platforms are bought centrally, though: PwC's release says its firms invested US$3 billion across the network in fiscal 2026, particularly in AI and technology, including its AI platform, PwC One.
How the Big 4 buy
This is general guidance from how large professional services firms run procurement, with the one rule that's written down.
- The independence check comes first. Under the SEC's auditor independence rule, 17 CFR 210.2-01(c)(3), an auditor isn't independent if it has "any direct or material indirect business relationship with an audit client." The rule excludes the firm providing professional services to the client or being "a consumer in the ordinary course of business." So if one of the four audits your company (your auditor is named in your annual report), it can still buy your product like any customer, but a joint offering, referral deal or reseller agreement is the kind of relationship its independence team will stop. The other three are open.
- A partner sponsors, functions approve. The buyer is usually a practice leader (audit innovation, tax technology, a consulting offering) or a firm-wide function such as IT, the chief operating officer's team or talent. Procurement, information security, risk and independence, and legal then review. Expect a security questionnaire and questions about where client data is stored.
- Budgets follow the fiscal year. Deloitte's year starts on 1 June, PwC's and EY's on 1 July and KPMG's on 1 October. Start budget conversations one or two quarters before.
- Avoid audit busy season. Audit teams are busiest in the first months of the calendar year, when December year-end audits close. Pitch tools for auditors in the second half of the year.
- Sell to the member firm, then expand. Win one country's firm, prove the result, and use it to reach the network's global technology or alliance teams.
Below the Big 4
The four are a small part of the US accounting market by count. County Business Patterns 2023, the Census Bureau's count of business locations with paid employees, shows 55,052 offices of certified public accountants (NAICS 541211) employing 604,209 people, with US$60.8 billion of annual payroll. Only 53 of those offices had 1,000 or more employees and 66 had 500 to 999; 35,650 had fewer than five. These are locations, not firms: a national firm counts once per office. For codes and definitions, see the NAICS code for accounting; for local counts, the market pages such as accounting firms in New York City.
Worked example: sizing a Big 4 opportunity
Illustrative example. The company, prices and assumptions are invented; the PwC figures are from its Global Annual Review 2026.
Verity Ledger (verityledger.example) sells audit analytics software at US$400 per user a year and is audited by one of the Big 4. It wants to size PwC's audit practice in the Americas.
| Step | Working | Result |
|---|---|---|
| PwC people in the Americas | 369,945 x 22% | About 81,400 |
| Of those, in Assurance, assuming the global 33% mix holds | 81,400 x 33% | About 26,900 |
| Ceiling if every one used the product | 26,900 x US$400 | About US$10.8 million a year |
| A realistic first pilot | 300 users x US$400 | US$120,000 a year |
Three decisions follow. First, Verity Ledger's own auditor can buy seats but can't be a co-selling partner, so its alliance conversations go to the other three. Second, PwC's year starts on 1 July, so the budget pitch goes in between February and April, and the pilot runs in the autumn, outside busy season. Third, the pilot sponsor is a partner leading audit technology in one member firm, not global procurement. Finding the right partners, and what each firm has said recently about its audit platform, is the slow research step; Bebop does it for each account in a list.
Common mistakes
- Treating "PwC" or "EY" as one buyer. Each country's firm decides for itself unless a network platform is involved.
- Comparing different years. KPMG's latest figures end in September 2025; the other three end in May or June 2026.
- Forgetting independence. Check whether the firm audits you, or your parent, before you propose any partnership.
- Quoting third-party rankings. Revenue and headcount change every year, and the firms publish their own; use those.
Next step: go below the Big 4 with the list of accounting firms, built from state board and PCAOB records.
Sources
- Deloitte reports FY2026 revenue, Deloitte, 24 September 2026
- 2025 Global Impact Report: performance metrics and reporting frameworks, Deloitte, 2025
- Deloitte US facts and figures, Deloitte, accessed 30 October 2026
- 2026 Transparency Report (Deloitte & Touche LLP), Deloitte, 2026
- PwC announces FY26 global financial performance, PwC, 19 October 2026
- Global Annual Review 2026, PwC, October 2026
- EY global revenue increases 4.7% to US$57b for fiscal year 2026, EY, 8 October 2026
- KPMG delivers 5.1% rise in global revenue, KPMG International, 16 December 2025
- 17 CFR 210.2-01, Qualifications of accountants, Electronic Code of Federal Regulations, accessed 30 October 2026
- 2023 County Business Patterns datasets, US Census Bureau, 2025
Written by the Bebop team at Blackpearl Group. Published .
Questions people ask
What are the Big 4 accounting firms?
Deloitte, PwC, EY and KPMG, the four largest professional services networks by revenue. Each sells audit and assurance, tax and legal, consulting and deal advisory through legally separate member firms in more than 130 countries. In their latest fiscal years they reported global revenue of US$74.5 billion, US$60.2 billion, US$57.0 billion and US$39.8 billion respectively.
Which Big 4 firm is the largest?
Deloitte, by both revenue and people. It reported US$74.5 billion of global revenue for the year to 31 May 2026 and nearly 500,000 people. PwC is second by revenue (US$60.2 billion for the year to June 2026), while EY is second by headcount with 415,182 people against PwC's 369,945. KPMG is the smallest, with US$39.8 billion and 276,030 people for the year to September 2025.
How many employees do the Big 4 have?
Roughly 1.56 million combined in their latest reports: Deloitte nearly 500,000 (fiscal 2026), EY 415,182 (June 2026), PwC 369,945 (30 June 2026) and KPMG 276,030 (30 September 2025). Deloitte's exact fiscal 2025 count was 473,050. These are network-wide totals across all countries, not US headcounts, which the firms mostly don't publish.
How much revenue do the Big 4 make in the US?
Only Deloitte publishes a US figure we found: Deloitte LLP and its subsidiaries recorded US$35.7 billion of US revenue in the year to 31 May 2025. The others report the Americas region, which also includes Canada and Latin America: PwC US$26.8 billion and EY US$25.9 billion for fiscal 2026. KPMG reports only growth for the Americas, 5.6% in fiscal 2025.
Are the Big 4 public companies?
No. Each is a network of privately owned member firms coordinated by a company that doesn't serve clients: Deloitte Touche Tohmatsu Limited, PricewaterhouseCoopers International Limited, Ernst & Young Global Limited and KPMG International Limited. In the US, Deloitte LLP is a Delaware limited liability partnership owned by its partners and principals. You can't buy shares in any of them.
Can a Big 4 firm buy from a company it audits?
Yes, as an ordinary customer. The SEC's independence rule, 17 CFR 210.2-01(c)(3), bars an auditor from any direct or material indirect business relationship with an audit client, but excludes being a consumer in the ordinary course of business. So the firm can buy your product on normal terms, while joint offerings, referral deals or reselling with the firm that audits you would be blocked.