Research

The Big Four Report 2026: Revenue, Headcount, and Audit Market Share for PwC, Deloitte, EY, and KPMG

By The Ledgerism Editorial Team · The Ledgerism Brief Editorial Team produces original, methodology-disclosed accounting and tax research—data trackers, databases, and reference guides built to be the most-cited source in the field. Every figure is verified against primary sources including FASB, the IRS, the PCAOB, NASBA, the AICPA, and state boards of accountancy.

A reference compilation of every verifiable statistic on the four largest global professional services networks, drawn from each firm’s own published Global Annual Review or Global Review and from independent regulatory and audit-market datasets. Every figure carries its exact fiscal year, geography, and source.

Important structural caveat (read first). PwC, Deloitte, EY, and KPMG are not single companies. Each is a global network of legally separate national member firms operating under a coordinating international entity. The revenue figures each network publishes are aggregated, self-reported, and not subject to a consolidated external audit in the way a public company’s accounts are. They are reported on differing fiscal-year ends and partly in different currencies, then translated to U.S. dollars. Treat cross-firm comparisons as approximate. This document states only figures the firms or independent datasets have published, and flags every limitation.

Executive summary

• The four networks reported combined aggregated global revenue of approximately US$220.4 billion for their respective fiscal years 2025 (sum of four self-reported figures: $56.9b + $70.5b + $53.2b + $39.8b).
• Deloitte reported the largest revenue, US$70.5 billion for the fiscal year ended 31 May 2025, becoming the first of the four to surpass US$70 billion (Deloitte Global, FY2025).
• PwC reported US$56.9 billion for the year ended 30 June 2025, up 2.7% in local currency and 2.9% in U.S. dollars (PwC Global Annual Review 2025).
• EY reported combined global revenue of US$53.2 billion for the year ended 30 June 2025, up 4.0% in local currency (EY Global Review 2025).
• KPMG reported globally aggregated revenue of US$39.8 billion on a continued-operations basis for the year ended 30 September 2025, up 5.1% in local currency (KPMG International, FY2025).
• Combined global headcount across the four networks exceeded 1.5 million people in FY2025; Deloitte alone reported over 470,000 (each firm’s FY2025 review).
• The Big Four audited 49.7% of U.S. SEC registrants in 2024 and 99.7% of S&P 500 audit fees in fiscal 2022 (Ideagen Audit Analytics).
• Global audit-quality regulators (IFIAR) found that 35% of inspected listed-PIE audit engagements had at least one finding in the 2025 survey, up from 34% in 2024 (IFIAR Survey of Inspection Findings 2025).

Key findings

1. Deloitte reported aggregate global revenue of US$70.5 billion for the fiscal year ended 31 May 2025, a 4.8% rise in local currency and 4.9% in U.S. dollars (Deloitte Global, FY2025).
2. PwC reported global revenue of US$56.9 billion for the year ended 30 June 2025, a 2.7% rise in local currency (PwC Global Annual Review 2025).
3. EY reported combined global revenue of US$53.219 billion for the year ended 30 June 2025, a 4.0% rise in local currency (EY Global Review 2025).
4. KPMG reported globally aggregated revenue of US$39.8 billion (continued-operations basis) for the year ended 30 September 2025, a 5.1% rise in local currency (KPMG International, FY2025).
5. Deloitte reported a global workforce of over 470,000 people in FY2025, up from 460,000 a year earlier (Deloitte Global, FY2025).
6. EY reported a global headcount of 406,209 at FY2025 year-end, up 3.4% from 393,025 (EY Global Review 2025).
7. KPMG reported global headcount of 276,030 in FY2025, up 1.8% year over year (KPMG International, FY2025).
8. PwC reported 364,000 people in FY2025 and disclosed a reduction of 5,600 staff over the 12 months to 30 June 2025 (PwC Global Annual Review 2025).
9. PwC’s largest service line in FY2025 was Advisory at US$24.3 billion, ahead of Assurance at US$19.8 billion and Tax and Legal Services at US$12.7 billion (PwC Global Annual Review 2025).
10. EY’s Assurance line generated US$17.877 billion in FY2025, its largest single service line (EY Global Review 2025).
11. The Big Four audited 49.7% of U.S. SEC registrants in 2024, up from 48.4% in 2023 (Ideagen Audit Analytics).
12. The Big Four audited 89.5% of U.S. large accelerated filers in 2024 (Ideagen Audit Analytics).
13. The Big Four accounted for 99.7% of S&P 500 audit fees in fiscal 2022 (Audit Analytics, reported via Visual Capitalist).
14. Approximately 98% of FTSE 350 audit fees in the UK went to the Big Four (Financial Reporting Council, 2023 data).
15. IFIAR member regulators found at least one inspection finding in 35% of inspected listed-PIE audits in the 2025 survey (IFIAR Survey of Inspection Findings 2025).

Section 1: Global revenue, FY2025

Each network reports aggregated global revenue on its own fiscal-year end. The figures below are each firm’s own published headline number. Because fiscal years differ (Deloitte ends 31 May, PwC and EY end 30 June, KPMG ends 30 September), the “FY2025” label denotes each firm’s own fiscal 2025, not a common calendar period.

Combined. The simple sum of the four self-reported FY2025 figures is approximately US$220.4 billion. This is an arithmetic total of figures with differing fiscal-year ends and is not a consolidated number.

Notes and limitations.
– KPMG’s FY2025 US$39.8 billion is reported on a “continued operations” basis, which excludes FY2024 and FY2025 revenue from businesses KPMG sold or exited (including the divestment of RYDGE Conseil from KPMG France in June 2025). On a full basis including divested operations, KPMG reported FY2025 revenue of US$40.2 billion versus FY2024 of US$38.4 billion (KPMG International, FY2025).
– Deloitte’s US$70.5 billion compares with US$67.2 billion in FY2024 (Deloitte Global, FY2024).
– PwC’s US$56.9 billion compares with US$55.4 billion in FY2024 (PwC, via CPA Practice Advisor citing PwC’s review).
– EY’s US$53.219 billion compares with US$51.221 billion in FY2024 (EY Global Review 2025).

Section 2: Revenue by service line, FY2025

Disclosure of revenue by service line is inconsistent across the four networks. PwC and EY publish U.S.-dollar amounts per service line. Deloitte publishes only growth rates by business unit for FY2025, not U.S.-dollar splits. KPMG publishes growth rates by function; its FY2025 announcement emphasized growth rates rather than per-function U.S.-dollar amounts.

PwC service lines, FY2025 (year ended 30 June 2025)

(PwC’s overall growth was 4.5% Advisory, 1.7% Assurance, and 1.0% Tax and Legal in local-currency terms per consulting press citing PwC; the U.S.-dollar growth rates above are from CPA Practice Advisor’s reporting of PwC’s figures.)

EY service lines, FY2025 (year ended 30 June 2025)

Deloitte business units, FY2025 (year ended 31 May 2025) — growth rates only

Deloitte realigned its capabilities into four business units during FY2025: Audit & Assurance; Tax & Legal; Strategy, Risk & Transactions; and Technology & Transformation. The FY2025 announcement disclosed growth rates, not U.S.-dollar revenue per unit.

Limitation. Deloitte’s FY2025 release does not provide U.S.-dollar revenue by business unit, and the FY2025 unit structure is not directly comparable to the prior five-line structure (Audit & Assurance, Consulting, Financial Advisory, Risk Advisory, Tax & Legal) used through FY2024. Any FY2024-to-FY2025 line-level comparison is therefore not like-for-like.

KPMG functions, FY2025 (year ended 30 September 2025) — growth rates

For historical context, in FY2024 KPMG reported Advisory as its largest function at US$16.3 billion of client fees (KPMG International, FY2024).

Section 3: Headcount, FY2025

Note. PwC’s FY2025 review disclosed a net reduction of 5,600 staff over the year to 30 June 2025. The four networks’ combined FY2025 headcount exceeds 1.5 million people.

Section 4: Regional / Americas performance, FY2025

The networks report regional splits with varying granularity. The Americas is the largest region for most.

EY additional regional detail, FY2025: EMEIA US$21.110 billion (+5.5% local currency); Asia-Pacific US$7.368 billion (+2.3%) (EY Global Review 2025).

PwC additional regional detail, FY2025: EMEA US$22.5 billion (+2.5%); Asia US$8.8 billion (-4.1%) (PwC, via consulting.us citing PwC’s review).

Section 5: U.S. member-firm revenue

Critical disclosure note. Only Deloitte separately discloses U.S. member-firm revenue as a primary, firm-published figure. PwC, EY, and KPMG do not publish standalone U.S.-firm revenue. For those three, the best available source is Inside Public Accounting (IPA), which ranks firms by U.S. net revenue from firm-submitted survey data. IPA is a reputable secondary source and is labeled as such below. IPA reports U.S. net revenue (excludes pass-through/subcontractor costs), whereas Deloitte discloses U.S. gross revenue, so the figures are not directly comparable.

Deloitte’s primary disclosure: “Deloitte LLP and its subsidiaries recorded $35.7 billion in U.S. revenues in the fiscal year ended May 31, 2025” (Deloitte US Facts & Figures).

Limitations.
– PwC, EY, and KPMG U.S.-firm revenue figures are IPA secondary estimates, not firm disclosures.
– U.S.-specific headcount is not separately disclosed by any of the four firms from a primary source; only global (and, for EY, an Americas headcount of 92,030) figures are published.
– IPA did not label an exact fiscal year for its 2025 ranking; it reflects firms’ most recently completed fiscal years, largely FY2024.

Section 6: Audit market share among public companies

United States (Ideagen Audit Analytics, “Who Audits Public Companies”)

• The Big Four audited 49.7% of U.S. SEC registrants in 2024, up from 48.4% in 2023 (Ideagen Audit Analytics).
• In 2024, the total universe was 6,285 SEC registrants audited by 228 firms, down from 6,607 registrants and 239 firms in 2023 (Ideagen Audit Analytics).
• Per-firm 2024 client counts: Deloitte 901 (14.3%) and EY 869 (13.8%) (Ideagen Audit Analytics).
• The 10 largest auditors handled about 65% of SEC-registrant audits in 2024 (down from roughly 68% prior year) (Ideagen Audit Analytics).
• The Big Four audited 89.5% of U.S. large accelerated filers in 2024, roughly unchanged from 2023; the Big Four plus Grant Thornton and BDO audited 94.9% (Ideagen Audit Analytics).
• EY led large accelerated filers with 540 clients (26.7%) in 2024 (Ideagen Audit Analytics).

Most recent Ideagen edition (per-firm counts as reported in trade press). Ideagen’s most recent “Who Audits Public Companies” edition reported per-firm SEC-registrant counts of Deloitte 926 (about 15%), EY 799 (about 13%), PwC 744 (about 12%), and KPMG 639 (about 11%), with the top 10 firms at about 65% (Ideagen Audit Analytics, reported via Accounting Today). These per-firm counts are flagged as reported by trade press citing Ideagen rather than read from the primary whitepaper.

Historical benchmark by sales (U.S. GAO, primary but dated). The GAO reported that the largest four firms audited about 99% of all U.S. public-company sales in 2002, more than 78% of all U.S. public companies, and more than 97% of public companies with sales over $250 million (GAO-03-864, July 2003). This is 2002 data and is presented only as a historical concentration benchmark, not a current figure.

S&P 500

• The Big Four accounted for 99.7% of S&P 500 audit fees in fiscal 2022; per firm, PwC US$1.9 billion, EY US$1.5 billion, Deloitte US$1.2 billion, and KPMG US$739 million, of US$5.3 billion total S&P 500 audit fees (Audit Analytics, reported via Visual Capitalist).
• By number of companies, the Big Four audited the large majority of the S&P 500 in 2024; an independent aggregator reported 488 of 500 (about 97.6%), split EY 156, PwC 150, Deloitte 108, KPMG 74 (big4stats.com). This per-company breakdown is flagged as an independent aggregator, not a primary regulator dataset.

United Kingdom (Financial Reporting Council)

• The Big Four earned about 98% of FTSE 350 audit fees (FRC, 2023 data).
• The Big Four audited approximately 99 of the FTSE 100 in 2022 (FRC Key Facts and Trends, via secondary reporting).
• Non-Big-Four firms held 41 FTSE 350 audits in 2023, up from 35 in 2022 (FRC).
• The Big Four earned about 90% of fees across the broader UK PIE market (FRC).

Section 7: Audit-quality regulatory findings

IFIAR (International Forum of Independent Audit Regulators)

IFIAR’s annual survey aggregates member regulators’ inspection results for audits performed by the member firms of the six largest global networks (the Global Public Policy Committee, or GPPC, firms: the Big Four plus the BDO and Grant Thornton networks).

• In the 2025 survey, 35% of inspected listed-PIE audit engagements had at least one finding, up from 34% in 2024 (IFIAR, reported via Thomson Reuters).
• The 2025 survey covered 836 listed-PIE audit inspections, of which 292 had at least one finding (IFIAR, via Thomson Reuters).
• The average number of findings per inspected PIE audit with findings was 3.3 in 2025, versus 3.2 in 2024 (IFIAR, via Thomson Reuters).
• The proportion of audits with at least one finding fell from 47% in 2014 to a low of 26% in 2022, then rose each year to 35% in 2025 (IFIAR, via Thomson Reuters).

PCAOB inspections (U.S., 2023 inspection year, Part I.A deficiency rates)

The PCAOB inspects a sample of each large firm’s audits annually and reports the share with at least one Part I.A deficiency. These are sample-based rates, not firm-wide failure rates.

Limitation. 2023 is the most recent full set widely reported with per-firm Big Four Part I.A rates. A 2024 inspection cycle exists, but per-firm Big Four 2024 rates were not confirmed for this compilation.

Section 8: Original synthesis (derived insights)

These three derived metrics are calculated from the verified figures above. Each states its formula, inputs, and limitations. They are simple arithmetic from self-reported revenue and are subject to the same self-reporting and fiscal-year-mismatch caveats.

Insight 1: Revenue per head, FY2025

Formula: global revenue / global headcount. Inputs: each firm’s FY2025 revenue and headcount (Sections 1 and 3).

Limitation: headcount figures are period-end or approximate, fiscal years differ, and “headcount” definitions (partners plus staff, full-time equivalents) are not standardized across firms. Treat as indicative only.

Insight 2: FY2025 revenue growth ranking (local currency)

Formula: each firm’s self-reported local-currency growth, ranked. Inputs: Section 1.

1. KPMG: +5.1%
2. Deloitte: +4.8%
3. EY: +4.0%
4. PwC: +2.7%

Limitation: local-currency growth removes FX translation effects but reflects different fiscal-year periods (KPMG’s year runs three months later than Deloitte’s). KPMG’s rate is on a continued-operations basis.

Insight 3: Service-line mix where disclosed (FY2025 share of revenue)

Formula: service-line revenue / total revenue, for the two firms (PwC, EY) that disclose U.S.-dollar service-line splits. Inputs: Section 2.

Limitation: only PwC and EY disclose U.S.-dollar service-line revenue; Deloitte and KPMG disclose growth rates only, so a four-firm comparison is not possible. EY’s “Advisory/Consulting” column here combines Consulting and Strategy and Transactions. Shares are computed from the firms’ own published figures and may not sum to exactly 100% due to rounding.

Section 9: Charts to create

1. FY2025 global revenue bar chart. Data: four firms’ FY2025 revenue (Section 1). Source: firms’ reviews. Insight: Deloitte’s lead and the gap to KPMG. Citation-worthy because it is the canonical ranking journalists reproduce annually.
2. Revenue growth comparison (local currency, FY2025). Data: Section 1 growth column. Insight: KPMG and Deloitte outpacing PwC. Useful for trend stories.
3. Service-line mix, PwC vs EY (FY2025). Data: Section 2 plus Insight 3. Insight: Advisory/Consulting is the largest line for both. Citation-worthy for the “consulting overtakes audit” narrative.
4. U.S. SEC-registrant audit share over time. Data: Big Four share 48.4% (2023) to 49.7% (2024), with universe shrinking from 6,607 to 6,285 (Ideagen). Insight: rising share of a shrinking pool.
5. IFIAR findings rate time series. Data: 47% (2014) to 26% (2022) to 35% (2025). Insight: the recent reversal in audit-quality findings.
6. PCAOB 2023 Part I.A deficiency rates by Big Four firm. Data: Section 7. Insight: wide spread (PwC 18% to EY 37%).

Methodology

• Source selection. Priority was given to each firm’s own published Global Annual Review / Global Review / press release (Tier 1 for that firm’s self-reported figures), independent regulators (GAO, FRC, IFIAR, PCAOB; Tier 1), and the Ideagen Audit Analytics dataset (Tier 1/2 for audit market share). Reputable trade press (Accounting Today, CPA Practice Advisor, Thomson Reuters, consulting.us) was used only where it explicitly cited a firm’s or regulator’s own figures, and is labeled accordingly.
• Inclusion rule. A statistic was included only if a credible source with a working URL and an identifiable date supported it. Each figure carries its fiscal year and geography.
• Exclusion rule. Subscription-gated estimates (for example, Statista’s U.S.-revenue values for firms that do not disclose them) were excluded because they could not be independently verified and are themselves secondary. Speculative or characterizing statements about the named firms were excluded.
• Handling conflicts. Where a firm’s local-currency and U.S.-dollar growth rates differed (for example, PwC 2.7% vs 2.9%), both are stated and labeled. Where editions of a dataset differed (Ideagen’s 2024 full-year vs most recent edition), the better-documented 2024 full-year figures are presented as the primary set and the newest per-firm counts are presented separately and flagged.
• Derived figures. The three synthesis metrics are simple arithmetic on the verified inputs, with formulas shown.
• Limitations. All four networks’ revenue is self-reported, aggregated across legally separate member firms, and not consolidated-audited. Fiscal years differ. Service-line and U.S.-firm disclosure is inconsistent. Audit-quality inspection rates are sample-based.
• Date of last update: 2026-06-29.

Source quality ranking

Tier 1 (primary: firm disclosures, government, regulators, official datasets)
– PwC Global Annual Review 2025 (pwc.com)
– Deloitte Global FY2025 revenue announcement and Deloitte US Facts & Figures (deloitte.com)
– EY Global Review 2025 newsroom (ey.com)
– KPMG International FY2025 press release (kpmg.com)
– U.S. Government Accountability Office, GAO-03-864 (govinfo.gov)
– UK Financial Reporting Council, Key Facts and Trends / competition updates (frc.org.uk)
– IFIAR Survey of Inspection Findings (ifiar.org)
– PCAOB inspection reports (pcaobus.org)
– Ideagen Audit Analytics, “Who Audits Public Companies” (ideagen.com)

Tier 2 (credible market research / public-data aggregators)
– Inside Public Accounting Top 500 (U.S. firm net-revenue rankings)
– Visual Capitalist / Voronoi (presenting Audit Analytics S&P 500 fee data)
– big4stats.com (S&P 500 per-firm company counts)

Tier 3 (reputable journalism quoting primary figures)
– Accounting Today, CPA Practice Advisor, Thomson Reuters Tax, consulting.us, GRC Report, AuditUpdate

Excluded and why
– Statista U.S.-revenue pages: subscription-gated, secondary estimates, not independently verifiable.
– Older Audit Analytics “over 99% of S&P 500” (2017): superseded by the FY2022 99.7%-of-fees figure for current use; retained only as historical context.
– Any unsourced “1.5 million employees / $220 billion” round numbers from secondary blogs: replaced with sums of the four verified figures.

Citation format (for major statistics)

• Source: PwC, Global Annual Review 2025 (year ended 30 June 2025).
• Source: Deloitte Global, FY2025 revenue announcement (year ended 31 May 2025).
• Source: EY, Global Review 2025 (year ended 30 June 2025).
• Source: KPMG International, FY2025 results (year ended 30 September 2025), continued-operations basis.
• Source: Ideagen Audit Analytics, “Who Audits Public Companies,” 2024 data.
• Source: Audit Analytics, S&P 500 auditor market share, fiscal 2022 (via Visual Capitalist).
• Source: UK Financial Reporting Council, Key Facts and Trends in the Accountancy Profession, 2024 (2023 data).
• Source: IFIAR, Survey of Inspection Findings 2025.
• Source: PCAOB, 2023 annual inspection reports (Part I.A deficiency rates).
• Source: Deloitte US, Facts & Figures (U.S. revenue, FY ended 31 May 2025).
• Source: Inside Public Accounting, Top 500 Firms ranking, 2025 (U.S. net revenue, secondary).

Journalist-friendly additions

Most quotable statistics

• Deloitte became the first of the four networks to surpass US$70 billion in revenue, reporting US$70.5 billion for the year ended 31 May 2025 (Deloitte Global, FY2025).
• The four networks reported a combined approximately US$220.4 billion in aggregated global revenue for fiscal 2025.
• The Big Four audited 49.7% of U.S. SEC registrants in 2024 and 99.7% of S&P 500 audit fees in fiscal 2022 (Ideagen Audit Analytics; Audit Analytics).
• PwC cut its global workforce by 5,600 in the year to 30 June 2025, ending at 364,000 (PwC Global Annual Review 2025).
• IFIAR regulators found at least one finding in 35% of inspected listed-PIE audits in the 2025 survey, the highest since 2018 and up from a 26% low in 2022 (IFIAR).

Data limitations

• Revenue is self-reported, aggregated across separate member firms, and not consolidated-audited.
• Fiscal years differ (31 May to 30 September), so the combined total is an arithmetic sum, not a like-period figure.
• Only Deloitte discloses U.S.-firm revenue from a primary source; PwC, EY, and KPMG U.S. figures are secondary IPA estimates.
• Deloitte and KPMG disclose service-line growth rates only, not U.S.-dollar splits, for FY2025.
• PCAOB rates are sample-based per inspection year; the most recent confirmed per-firm Big Four set is the 2023 cycle.

Downloadable dataset — recommended fields (for a CSV / Dataset schema)

firm, network_entity, fiscal_year, fiscal_year_end_date, metric (revenue / headcount / service_line_revenue / audit_share / inspection_finding_rate), service_line, geography, value, unit (USD_billion / count / percent), currency_basis (local / USD), growth_local_pct, growth_usd_pct, basis_note (gross / net / continued_operations), source_name, source_tier, source_url, source_date, limitation_flag.

150-word press summary

The four largest global professional services networks reported a combined total of approximately US$220.4 billion in aggregated global revenue for their fiscal year 2025, according to each firm’s own published review. Deloitte led with US$70.5 billion for the year ended 31 May 2025, the first time any of the four passed US$70 billion. PwC reported US$56.9 billion (year ended 30 June 2025), EY US$53.2 billion (30 June 2025), and KPMG US$39.8 billion on a continued-operations basis (30 September 2025). KPMG posted the fastest local-currency growth at 5.1%; PwC the slowest at 2.7%, and PwC reduced headcount by 5,600. The four firms continue to dominate public-company auditing, covering 49.7% of U.S. SEC registrants in 2024 and 99.7% of S&P 500 audit fees in fiscal 2022. Global audit regulators (IFIAR) reported inspection findings in 35% of listed-PIE audits in 2025. All revenue figures are self-reported and not consolidated-audited.

Suggested headlines

1. The Big Four 2026: Every Verified Revenue, Headcount, and Audit-Share Number
2. Deloitte Crosses US$70 Billion as the Big Four Near US$220 Billion Combined in FY2025
3. Who Audits America: The Big Four Hold 49.7% of SEC Registrants and 99.7% of S&P 500 Audit Fees
4. The Big Four by the Numbers: FY2025 Revenue, Growth, and Service-Line Mix Compared
5. PwC Shrinks, KPMG Grows Fastest: Reading the Big Four’s FY2025 Results

FAQs

1. What was the Big Four’s combined revenue in 2025? Approximately US$220.4 billion, the sum of Deloitte US$70.5b, PwC US$56.9b, EY US$53.2b, and KPMG US$39.8b for their respective FY2025 (firms’ reviews).
2. Which is the largest by revenue? Deloitte, at US$70.5 billion for the year ended 31 May 2025 (Deloitte Global).
3. Which grew fastest in FY2025? KPMG, at 5.1% in local currency, on a continued-operations basis (KPMG International).
4. How many people do the Big Four employ? Over 1.5 million combined in FY2025: Deloitte 470,000+, EY 406,209, PwC 364,000, KPMG 276,030 (firms’ reviews).
5. Did any firm cut staff? Yes; PwC reduced headcount by 5,600 in the year to 30 June 2025 (PwC Global Annual Review 2025).
6. What share of U.S. public companies do they audit? 49.7% of SEC registrants in 2024, and 89.5% of large accelerated filers (Ideagen Audit Analytics).
7. What about the S&P 500? The Big Four accounted for 99.7% of S&P 500 audit fees in fiscal 2022 (Audit Analytics via Visual Capitalist).
8. What is the largest service line now? For PwC and EY, Advisory/Consulting is the largest line at about 42-43% of revenue in FY2025 (firms’ reviews).
9. How reliable are these revenue figures? They are self-reported and aggregated across separate member firms, and not externally consolidated-audited; treat them as the firms’ own disclosures.
10. What do audit regulators find? IFIAR found at least one inspection finding in 35% of inspected listed-PIE audits in 2025; the 2023 PCAOB Part I.A deficiency rate for the Big Four combined was 26% (IFIAR; PCAOB).

Sources

1. PwC, Global Annual Review 2025 — https://www.pwc.com/gx/en/about/global-annual-review.html and financial performance — https://www.pwc.com/gx/en/about/global-annual-review/financial-performance.html and press release — https://www.pwc.com/gx/en/news-room/press-releases/2025/pwc-global-revenues-rise.html
2. PwC FY2025 figures reported by consulting.us — https://www.consulting.us/news/12580/pwc-grows-global-revenue-by-27-to-569-billion
3. PwC FY2025 figures reported by CPA Practice Advisor — https://www.cpapracticeadvisor.com/2025/10/28/pwc-reports-global-revenue-of-56-9-billion-in-2025/171838/
4. Deloitte Global, FY2025 revenue announcement — https://www.deloitte.com/global/en/about/press-room/global-revenue-announcement.html
5. Deloitte Global, FY2024 revenue announcement — https://www.deloitte.com/cy/en/about/press-room/global-revenue-announcement.html
6. Deloitte US, Facts & Figures — https://www.deloitte.com/us/en/about/story/facts-and-figures.html
7. EY, Global Review 2025 (FY2025 revenue announcement) — https://www.ey.com/en_gl/newsroom/2025/10/ey-announces-global-revenue-of-us-53-2b-for-fiscal-year-2025
8. EY, FY2024 revenue announcement — https://www.ey.com/en_gl/newsroom/2024/10/ey-reports-global-revenue-of-51-point-2-billion-us-dollars-for-fiscal-year-2024
9. KPMG International, FY2025 results — https://kpmg.com/xx/en/media/press-releases/2025/12/kpmg-delivers-rise-in-global-revenue.html
10. KPMG International, FY2024 results — https://kpmg.com/xx/en/media/press-releases/2024/12/robust-growth-for-kpmg-as-global-revenues-rise-5-percent-to-us-dollar-38-point-4-billion.html
11. Ideagen Audit Analytics, “Who Audits Public Companies” (2024 data, via AuditUpdate) — https://www.auditupdate.com/post/who-audits-public-companies-large-firms-dominate-although-the-pie-is-shrinking
12. Big Four 2024 SEC audit share (Accounting Today) — https://www.accountingtoday.com/news/big-four-firms-lose-a-bite-of-share-for-audits-in-2024
13. Big Four SEC market share, most recent Ideagen edition (Accounting Today) — https://www.accountingtoday.com/news/big-four-hold-onto-their-share-of-sec-market
14. Ideagen “Who Audits Public Companies 2025” whitepaper — https://www.ideagen.com/resources/whitepapers/who-audits-public-companies-2025
15. Audit Analytics S&P 500 audit fees / market share (via Visual Capitalist) — https://www.visualcapitalist.com/big-four-audit-fees-market-share-s-p-500/
16. S&P 500 auditor analysis by company count (big4stats) — https://big4stats.com/sp-500-auditor-analysis/
17. U.S. GAO, GAO-03-864, Public Accounting Firms: Mandated Study on Consolidation and Competition (2003) — https://www.govinfo.gov/content/pkg/GAOREPORTS-GAO-03-864/html/GAOREPORTS-GAO-03-864.htm
18. UK Financial Reporting Council, Key Facts and Trends 2024 — https://www.frc.org.uk/news-and-events/news/2024/09/frc-publishes-key-accountancy-and-audit-facts-and-trends-report-for-2024/
19. UK FRC, Audit market and competition developments 2024 — https://media.frc.org.uk/documents/Audit_market_and_competition_developments_2024.pdf
20. IFIAR, Survey of Inspection Findings 2025 — https://www.ifiar.org/?wpdmdl=19599 and Annual Inspection Findings Survey — https://www.ifiar.org/activities/annual-inspection-findings-survey/
21. IFIAR 2025 survey reported by Thomson Reuters Tax — https://tax.thomsonreuters.com/news/global-audit-regulators-report-slight-rise-in-inspection-findings-in-2025-survey/
22. PCAOB, 2023 annual inspection reports — https://pcaobus.org/news-events/news-releases/news-release-detail/pcaob-posts-2023-annual-inspection-reports-alongside-staff-observations-new-charts-to-boost-transparency and Big Four Part I.A rates (via AuditUpdate) — https://www.auditupdate.com/post/2023-pcaob-large-firm-inspection-reports
23. Inside Public Accounting Top 500 ranking 2025 (via CPA Practice Advisor) — https://www.cpapracticeadvisor.com/2025/08/19/inside-public-accounting-releases-ranking-list-of-top-500-firms/167635/

Related research

More original, sourced datasets from The Ledgerism Brief:

• CPA Industry Report + Shortage Index — Workforce, salary, firms, and the CPA shortage.
• The State of Accounting 2026 — The U.S. accounting profession by the numbers.
• AI in Accounting Report — Adoption rates and the Automation Index.
• Accounting Salary Database — Pay by state, metro, role, and experience.
• FASB Standards Report — ASUs issued and adoption of major standards.
• SEC Restatement Report — Restatements by year, type, and cause.