
Industry research
Scope
US
Companies
147
Table of contents

What does the accounting, auditing and taxation services market landscape look like in the US?
The US accounting, auditing and taxation services market is consolidated at the top, with the Big Four (i.e. Deloitte, EY, KPMG, PwC) dominating public-company audits. Mid-tier firms (e.g. Baker Tilly, Grant Thornton) focus on the middle market, high-growth businesses and family-owned companies. Beneath them, >80k smaller CPA firms compete through strong regional presence. Consolidation has been significant, with ~50% of the top 300 firms merging in the past decade (Thomson Reuters, June 2025). Much of this activity has been driven by mid-tier players seeking scale, niche expertise and entry into adjacent areas (e.g. consulting). Recent trends in the industry show a shift away from the traditional partnership model toward alternative practice structures. Under this model, firms are split into two entities, with the attest entity remaining CPA-owned to meet independence requirements and the advisory and tax entity able to accept PE investment, fueling M&A roll-ups. Meanwhile, the Big Four have focused their acquisitions on strengthening consulting capabilities. Generalist firms have refined their client bases and deepened relationships to strengthen their role as trusted advisors, opening up significant cross-selling opportunities in high-value advisory services. Deloitte exemplifies this shift, with consulting accounting for ~45% of its 2024 revenue, up from ~35% in 2015 (Deloitte, November 2024; The Wall Street Journal, September 2015). The specialist segment remains more fragmented, with firms typically focusing on distinct niches. They differentiate by combining deep expertise with technology-driven delivery models.
What is the level of investor activity in the US's accounting, auditing and taxation services industry?
Investor-led interest has been limited, with ~15% of identified US assets being backed by financial sponsors (October 2025). Herein, investor interest is fueled by (i) recurring revenue streams from compliance-driven audit requirements supported by a sticky customer base, (ii) adoption of technology (e.g. AI) that boosts cost savings and efficiency and (iii) evolving tax regulations fueling demand for specialized tax advisory. The main detractors relate to (i) heightened regulatory scrutiny of audit firms, (ii) rising uncertainty around potential tariffs on outsourcing, as well as (iii) a structural shortage of audit professionals.
What are the key ESG considerations in the US's accounting, auditing and taxation services industry?
ESG topics in the US accounting, auditing and taxation market relate to environmental, social and governance issues. In terms of environmental concerns, the industry is under pressure to reduce its carbon footprint from office operations and business travel. In response, firms adopt remote audits, virtual meetings, office consolidation and energy efficiency initiatives. Social challenges center on employee well-being, with heavy workloads and long hours affecting retention and the profession’s attractiveness. To address this, firms offer flexible schedules, hybrid work models, capped hours during off-season periods and expanded wellness and family care benefits. Lastly, governance risks arise from audit lapses and audit-advisory conflicts of interest, with regulators maintaining strict scrutiny on quality controls and independence. To mitigate these risks, firms invest in technology, strengthen training, establish independent oversight structures and adopt alternative practice models to separate audit from non-audit services.

The global auditing services market was valued at ~$337.8bn in 2023 and is expected to reach ~$451.2bn by 2028 (+5.9% CAGR 2023-2028; Technavio, July 2024)
The global accounting services sector is expected to grow from a market value of ~$652.3bn in 2023 to ~$804.3bn by 2028 (+4.4% CAGR 2023-2028; Benchmark International, September 2024)
Entrepreneurial activity and new business registrations in the US are expected to continue to rise, driving demand for accounting, audit and tax services. To illustrate, the US averaged ~430k new business applications per month in 2024, ~50% higher than pre-2020 norms, accelerating the number of businesses requiring bookkeeping setup, financial reporting and tax compliance services (Commerce Institute, September 2025; US Department of the Treasury, September 2024)
Evolving tax regulations fuel demand for specialized tax advisory, particularly for multistate and multinational firms. To illustrate, major tax laws (e.g. the Affordable Care Act (2010), the Tax Cuts and Jobs Act (2017)) contributed to >168% growth in Big 4 US tax practice revenues from 2000 to 2022 (The CPA Journal, July 2024; Grant Thorton, December 2023; OC&C expert interview)
The adoption of AI, machine learning and data analytics boost cost savings and efficiency for audit practices. These technologies drive improved accuracy, sharper anomaly detection and more efficient audit workflows, strengthening audit quality and profitability simultaneously (Escalon, April 2024; Journal of Accountancy, February 2024; FundCount, November 2023)
A persistent shortage of skilled professionals in the US audit sector constrains the industry’s ability to meet growing demand. The talent pool is shrinking, with CPA exam candidates down ~37% from 2016 to 2023, while ~75% of current CPAs are projected to retire within the next 15 years (Intuit, June 2025; Confederation of Asian and Pacific Accountants, March 2024)
Regulatory scrutiny of US audit firms is intensifying, increasing operational complexity and driving up compliance costs. Given the rise in audit lapses, the PCAOB (Public Company Accounting Oversight Board) issued record penalties of ~$35.7m (+78% YoY) in 2024 and adopted tougher standards, including AS 1000 (including a 14-day audit-documentation deadline vs. 45 days before) and QC 1000 (requiring annual firmwide QC evaluations), with updated confirmation requirements taking effect in 2025 (PCAOB, September 2025; PCAOB, March 2025; Reuters, February 2025)
Rising uncertainty around potential tariffs on outsourcing threatens the cost efficiency of offshore delivery models. The proposed Halting International Relocation of Employment (HIRE) Act, which introduces a 25% excise tax on outsourcing payments made to foreign workers and prohibits companies from claiming tax deductions on such payments, could significantly erode these advantages and compress profit margins (Forum, September 2025; KMK Ventures, September 2025)
With the full report, you’ll gain access to:
Detailed assessments of the market outlook
Insights from c-suite industry executives
A clear overview of all active investors in the industry
An in-depth look into 147 private companies, incl. financials, ownership details and more.
A view on all 410 deals in the industry
ESG assessments with highlighted ESG outperformers