European Audit Market Report [2025]: Fees, Firms & Trends

Key Takeaways

Where Big Four dominance is weakening (by engagement count) and where it isn't (by fee value)
How CSRD assurance is already affecting fee structures at firms in the Netherlands and France
Which mid-tier networks grew fastest in Europe in 2024, and what drove that growth
How to position your firm's fee proposals against the benchmarks in this report

Market size and growth

The European auditing services market crossed the €65 billion mark in 2025 according to Mordor Intelligence's market sizing report. External audit engagements account for 72.54% of that revenue. Internal audit outsourcing is growing faster (8.18% CAGR) but from a much smaller base.

The UK commands the largest single-country share at 29.64% of the European market. Germany holds the second position, with particularly strong mid-market audit demand driven by its Mittelstand economy. The BENELUX region (Belgium, Netherlands, Luxembourg) is growing at 8.16% CAGR, the fastest sub-regional growth rate in Europe, driven by regulatory harmonisation and cross-border M&A activity.

Banking, financial services, and insurance (BFSI) generated 31.35% of European audit demand in 2024. Financial audits specifically delivered 35.63% of total 2024 revenues. Information-system audits are projected to advance at 13.63% CAGR, outpacing every other service line as cyber-risk monitoring becomes inseparable from financial statement reliability.

The FRC's 2025 Audit Market and Competition Update confirmed that total PIE audit fees in the UK reached £1.4 billion for the 2023 reporting period (the most recent full-year data published). The median PIE audit fee for 2024 was £1 million, 7% higher than 2023. That 7% increase was well below the double-digit rises seen in 2021 and 2022, suggesting the post-pandemic fee correction is stabilising.

Big Four versus mid-tier: the fee and engagement gap

Two numbers from the FRC's 2025 report frame this section. Non-Big Four firms held 13% of FTSE 350 audit engagements in 2023, up from roughly 9% in 2020. But when measured by fees rather than engagements, non-Big Four firms held just 2% of FTSE 350 audit fee revenue in 2024.

That gap (13% of engagements, 2% of fees) tells a specific story. Mid-tier firms are winning smaller listed mandates. The larger, higher-fee mandates remain concentrated. PwC held 27% of FTSE 350 fee share in 2024 (up from 26% in 2023). EY held 23% (down from 24%). Deloitte and KPMG held the remainder among the Big Four.

At the EU level, the European Commission's 2024 audit market monitoring report (based on 2021 data, the most recent EU-wide dataset) found the Big Four accounted for 86% of revenue from PIE statutory audits and 71% of revenue from audits of other entities. Their average EU market share by number of PIE audits was 59%, down from 70% in 2018. In 13 EU member states, the Big Four are no longer the four largest firms by number of PIE opinions issued.

Mazars ranked as the fifth-largest firm in the EU PIE market with 7% market share by engagement count. BDO followed at 5%.

Measure by fee revenue, not engagement count

For non-Big 4 firms competing in the European mid-market, the practical implication is clear: winning by engagement count is happening. Winning by fee value is not. The engagements mid-tier firms pick up tend to be smaller, lower-fee clients. If you're building a practice strategy around PIE market share growth, measure it by fee revenue, not engagement count.

Where mid-tier firms are gaining ground

The mid-tier networks posted strong growth numbers in 2024. Grant Thornton International reported record global revenues of $8 billion for the year ending September 2024, growth of 8.8% in constant currency. Their Europe and Middle East region grew 11.6%, with the Netherlands specifically growing 10.8%. Assurance revenue (the segment that includes statutory audit) grew 11.9%, the fastest of any service line.

BDO reported $15 billion in global revenue for 2024. In the UK specifically, BDO's fee income grew 16% according to the Accountancy Age Top 50+50 rankings. Forvis Mazars (formed from the June 2024 merger of Mazars and Forvis) reported $5.2 billion in combined global revenue, with EMEA representing the fastest-growing region.

Baker Tilly International posted $5.62 billion in global revenue for 2024, with EMEA growing at 13%, driven by expansion in Belgium, France, Germany, Italy, the Netherlands, Poland, Spain, and the UK.

RSM reached $10 billion globally and reported the highest fee per partner (£3.9 million) among mid-tier firms in the UK market.

Private equity is accelerating the mid-tier consolidation story. Grant Thornton US sold a significant stake to New Mountain Capital in May 2024. Grant Thornton UK sold a majority stake to Cinven. These deals fund cross-border acquisitions and faster capability buildout, particularly in advisory, ESG assurance, and technology. BDO completed mergers in Austria (absorbing Grant Thornton partners), Italy (merging with Mazars Italy), and France (four local mergers). PE-backed consolidator Sumer in the UK grew fee income by 605% in a single year through aggressive acquisitions.

The two-directional pressure on independent firms

For SRA member firms and other independent practices in the Netherlands and wider Europe, the mid-tier consolidation wave creates pressure from two directions. From one side: mid-tier networks are becoming more competitive for the same mid-market mandates you target. From the other: rotation and tendering requirements mean clients leaving a Big Four firm don't always go to another Big Four firm. If you can demonstrate sector expertise and competitive pricing, the opportunity is real.

Country-level breakdown

Fee structures vary substantially across European jurisdictions. The FRC's 2025 report provides the most granular data for the UK:

ICB Industry (FTSE 350)	Average audit fee 2024	Change vs 2023
Energy	£13.0 million	Largest avg fee
Telecommunications	£9.7 million	Second largest
Health care	£8.1 million	Third largest
FTSE 350 median (all industries)	£1.0 million	+7%

Note that these figures reflect the FTSE 350 listed company population. Mid-market and non-listed audit fees are substantially lower.

Netherlands. The AFM's 2025 State of the Auditing and Reporting Industry report provided data from over 31,000 statutory audits of non-PIE firms (collected from 2023 through mid-2025). The AFM noted that non-PIE audit firms deployed increased FTEs on professional practice support, with average professional practice FTEs at PIE firms rising from 56.7 in 2023 to 66.6 in 2024. Compliance FTEs rose from 13.4 to 14.9.

Austria and Germany. Mottinger et al. (2023) found that audit fees increased post-EU Audit Reform in Austria, while fees in Germany actually decreased over the same period. Both markets saw increases in assurance services revenue and evidence of "lowballing" (lower first-year fees followed by subsequent increases).

France. France has the most established joint audit requirement in Europe. The fee impact of joint audits is debated, with academic studies finding effects ranging from no significant difference to increases above 25% (Delors Centre, 2024). The trade-off is between higher audit costs and potentially lower cost of capital through increased investor confidence.

CSRD and sustainability assurance: the fee uplift

The CSRD's impact on the audit fee market is now visible in actual data, not just projections.

In the Netherlands, Eumedion (the Dutch corporate governance body) reported an "unexpectedly large" 19% increase in assurance costs among domestic firms complying with CSRD for the 2024 reporting year. In France, the H2A (Haute Autorité de l'Audit) evaluated 91 companies subject to CSRD and found assurance costs ranged from 1% to 25% of total audit fees, with an average of 8%.

The Sustainability Reporting Navigator found that 90% of first-wave CSRD assurance engagements were performed by Big Four firms. Only 1% of reports received a qualified opinion from auditors.

CSRD assurance costs under limited assurance currently run at 20% to 30% of average financial audit fees, according to Position Green's analysis. The European Commission's original timeline called for a potential move to reasonable assurance by October 2028. The February 2025 Omnibus Proposal, however, removed the reasonable assurance requirement entirely, permanently maintaining the limited assurance level. This changes the fee outlook significantly: the expected cost escalation from limited to reasonable assurance will not materialise under the Omnibus framework.

The scope expansion is the bigger story. In the Netherlands, the AFM noted that CSRD-obligated companies will increase from roughly 95 (2024 financial year) to over 3,000 from 2025 onward. That's a 30x increase in the number of entities requiring sustainability assurance. For audit firms, this is the single largest source of new engagement volume in a generation.

The window for non-Big 4 firms

Big Four firms captured 90% of first-wave engagements, but first-wave companies were overwhelmingly large PIEs (the Big Four's natural client base). Second and third waves include mid-market companies more likely to consider mid-tier and independent firms. Non-Big 4 firms that build CSRD assurance capability now have a genuine opportunity.

Talent shortage and its effect on fees

Auditor supply is the constraint most directly affecting fee levels in 2025.

Mordor Intelligence's 2025 report estimated that qualified auditor supply in Europe lags demand by double-digit percentages, with senior-staff wages rising 23% in 2024 across the European audit market. That wage inflation feeds directly into engagement pricing.

The Quoted Companies Alliance (QCA) in the UK found that average audit fees for small and mid-cap listed companies rose 75% between 2017/18 and 2022/23, from £397,243 to £694,083. Companies on the Main Market with market capitalisation under £500 million paid an average of £547,000 more in audit fees over that period. The QCA attributed the increase to four factors: decreasing auditor availability, increased financial reporting and auditing standards, audit firms pursuing higher margins, and fewer auditors entering the profession.

The talent gap is most acute in IT audit and ESG assurance, where interdisciplinary expertise is required. Firms that can recruit, retain, or contract specialist talent have pricing power. Firms that can't are either turning away work or staffing engagements with under-qualified teams (a quality risk the AFM is explicitly watching for).

Worked example: benchmarking your firm's fee position

Client scenario: Vos & Dekker Machinebouw B.V., a Dutch manufacturing company with €38 million revenue, 145 employees, operations in two countries (Netherlands and Belgium), and no CSRD obligation (yet). Current audit fee: €42,000.

Step 1: Identify the comparable market segment

Vos & Dekker sits in the non-PIE mid-market segment. The AFM's non-PIE audit data covers this population. It's not FTSE 350 data. It's not Big Four territory.

Documentation note: Record the benchmark source and date. "Fee benchmarked against AFM non-PIE audit data (2025 report, covering 31,000+ statutory audits) and Mordor Intelligence European market sizing (2025)."

Step 2: Calculate the fee-to-revenue ratio

€42,000 / €38,000,000 = 0.11% of revenue.

For context, the Manufacturers Alliance found that US manufacturers paid an average of 0.07% of revenue in audit fees in 2023. European mid-market ratios tend to run higher due to smaller entity sizes and proportionally greater audit complexity. A range of 0.08% to 0.15% is typical for a €30-50 million revenue non-PIE manufacturing entity in the Netherlands.

Documentation note: "Fee-to-revenue ratio of 0.11% falls within the expected range for a non-PIE manufacturing entity of this size. No anomaly identified."

Step 3: Assess upcoming fee pressure points

Vos & Dekker has 145 employees. Under the original CSRD scope, it would fall below the 250-employee threshold. Under the Omnibus Proposal's revised thresholds (1,000 employees, €450 million turnover), it would remain out of scope entirely. But if Vos & Dekker's largest customer is a CSRD-obligated entity requesting supply chain ESG data, the audit scope may expand indirectly.

Documentation note: "CSRD not directly applicable under current or proposed thresholds. Monitor supply chain data requests from CSRD-obligated customers. No fee uplift budgeted for sustainability assurance in 2026."

Step 4: Position the fee proposal

Current fee of €42,000 for a two-country, €38 million revenue manufacturing audit is defensible. A reviewer would see a ratio within range and a documented basis for the benchmark. If proposing a fee increase for 2026, the 7% year-on-year increase seen in UK PIE median fees (FRC, 2025) and the 23% senior-staff wage inflation reported by Mordor Intelligence provide a data-backed justification. A 5-8% increase (€44,100 to €45,360) would be consistent with market trends without overreaching.

Documentation note: "Proposed fee increase of [X]% supported by FRC 2025 median fee growth data and Mordor Intelligence European wage inflation data. Documented in fee proposal letter dated [date]."

Practical checklist for 2026 fee planning

Pull your firm's average fee-to-revenue ratio by sector. Compare it against the FRC's FTSE 350 industry averages and the Manufacturers Alliance's 0.07% manufacturing benchmark. If your ratio is below 0.08% for a complex mid-market entity, you are likely under-pricing.
Identify which clients will fall within CSRD scope for the 2025 or 2026 financial year. For each, estimate the limited assurance fee at 20-30% of the current financial audit fee (Position Green benchmark). Build this into your engagement letter before fieldwork begins.
Check the AFM's 2025 State of the Auditing and Reporting Industry for updated data on non-PIE audit quality indicators. Use these to benchmark your firm's FTE allocation on professional practice support against the market average (66.6 FTEs at PIE firms, with a rising trend for non-PIE firms).
Review your staff cost assumptions. If you haven't increased billing rates to reflect 2024's 23% senior-staff wage inflation, your margins are eroding. Calculate the gap between your average hourly cost and your average billing rate for each grade.
Document every fee benchmark source used in engagement letters and fee proposals. Named sources with dates. The FRC's 2025 report, the AFM's 2025 report, and Mordor Intelligence's market sizing are all publicly available and traceable.

Common mistakes in fee benchmarking

Comparing non-PIE mid-market fees against FTSE 350 or S&P 500 averages. Those populations are structurally different. The IAA's 2025 report found average US audit fees of $2.726 million, which has no relevance to a €40,000 Dutch mid-market audit.

Ignoring the engagement-count versus fee-value distinction. The FRC data shows mid-tier firms hold 13% of FTSE 350 engagements but 2% of fee revenue. Quoting engagement market share in a pitch without acknowledging the fee gap overstates your firm's competitive position.

Failing to budget for CSRD assurance as a separate fee line. The AFM expects over 3,000 Dutch entities to require sustainability assurance from the 2025 financial year onward. Firms that roll this into existing audit fees rather than pricing it separately will under-recover.

Get practical audit insights, weekly.

No exam theory. Just what makes audits run faster.

No spam — we're auditors, not marketers.

Frequently asked questions

How large is the European audit services market in 2025?

The European auditing services market reached approximately €65.9 billion in 2025, growing at a compound annual rate of 6.33% with projected growth to €95.25 billion by 2030 (Mordor Intelligence, 2025). External audit engagements account for 72.54% of that revenue. The UK commands the largest single-country share at 29.64% of the European market.

What market share do Big Four firms hold in Europe?

Non-Big Four firms held 13% of FTSE 350 audit engagements in 2023, up from roughly 9% in 2020. But when measured by fees rather than engagements, non-Big Four firms held just 2% of FTSE 350 audit fee revenue in 2024. At the EU level, the Big Four accounted for 86% of revenue from PIE statutory audits and 71% of revenue from audits of other entities. Their average EU market share by number of PIE audits was 59%, down from 70% in 2018.

How much does CSRD assurance cost?

CSRD assurance costs under limited assurance currently run at 20% to 30% of average financial audit fees, according to Position Green's analysis. In the Netherlands, Eumedion reported an unexpectedly large 19% increase in assurance costs among domestic firms complying with CSRD for the 2024 reporting year. In France, the H2A found assurance costs ranged from 1% to 25% of total audit fees, with an average of 8%. The February 2025 Omnibus Proposal removed the reasonable assurance requirement, permanently maintaining the limited assurance level.

Which mid-tier firms are growing fastest in Europe?

Grant Thornton International reported record global revenues of $8 billion for the year ending September 2024, with their Europe and Middle East region growing 11.6%. BDO reported $15 billion in global revenue. Baker Tilly posted $5.62 billion with EMEA growing at 13%. RSM reached $10 billion globally. Private equity is accelerating consolidation, with Grant Thornton UK selling a majority stake to Cinven and BDO completing mergers across Austria, Italy, and France.

How is the talent shortage affecting audit fees?

Mordor Intelligence estimated that qualified auditor supply in Europe lags demand by double-digit percentages, with senior-staff wages rising 23% in 2024. The QCA found that average audit fees for UK small and mid-cap listed companies rose 75% between 2017/18 and 2022/23. The talent gap is most acute in IT audit and ESG assurance, where interdisciplinary expertise is required. Firms that can recruit specialist talent have pricing power.