Top 20 Accounting Firms in the US: A Complete 2026 Guide

Quick answer: The top accounting firms in the US in 2026 are led by the Big Four (Deloitte, PwC, EY, KPMG), followed by large national players like RSM, BDO, Grant Thornton, and Forvis Mazars, and specialized outsourcing partners such as Corient Business Solutions that help CPA firms scale bookkeeping, payroll, tax, and advisory work without adding in-house headcount.

Today's leading accounting firms look nothing like the traditional audit-and-tax shops of a decade ago. The strongest names in the industry have become technology-driven advisory partners, guiding businesses through compliance, automation, AI adoption, tax strategy, and growth planning — not just closing the books.

Why 2026 Is a Turning Point for US Accounting Firms

Firms across the country are under real pressure this year. Compliance requirements keep expanding, IRS reporting rules keep changing, AI-powered accounting software is reshaping workflows, staffing shortages remain severe, and clients expect faster, more strategic service than ever before.

That raises an obvious question: how does a firm stay profitable and maintain quality under all that pressure?

A Real-World Example

One US CPA firm saw a client's business grow quickly — a good problem, but a costly one. Staff became overloaded with bookkeeping reviews, payroll deadlines, sales tax filings, and 1099/W-2 compliance checks. Hiring more people was slow and expensive, and turnaround times began to slip.

Instead of continuing to recruit, the firm turned to outsourced bookkeeping and compliance support. Within months, bottlenecks eased, and senior staff were freed up for higher-value advisory work.

This scenario is becoming the norm, not the exception. According to the 2026 Corporate Finance & Accounting Talent Study, 61% of finance leaders report at least a minor shortage of accounting and finance talent, with a talent shortage index of 77% — a gap that's driving demand for outsourced compliance support and specialized finance expertise.

What Makes an Accounting Firm Top-Tier in 2026

Revenue alone doesn't determine which firms make it onto a "best of" list. A few consistent traits separate the top 20 from the rest of the field.

Technical Expertise

Leading firms keep investing in core capabilities, including:

• Audit planning

• Tax advisory

• Corporate finance

• Outsourcing services

• Business consulting

• Compliance services

Clients increasingly want strategic guidance rather than basic bookkeeping alone.

Technology Adoption

To keep up with evolving IRS e-filing rules, state-level sales tax complexity, and stricter enforcement, top firms are investing in:

• Cloud accounting systems

• AI-powered automation

• Digital audit tools

• Workflow management platforms

• Real-time reporting dashboards

These tools improve accuracy while cutting down manual work.

Industry Specialization

Many top-tier firms have built deep expertise in specific sectors, such as:

• Construction

• Healthcare

• E-commerce

• Staffing and recruitment

• Real estate

• Manufacturing

• Technology

Sector focus allows firms to offer more tailored, relevant advice.

Scalability

Standardized workflows and automation let top firms grow their service capacity without sacrificing quality — a key differentiator as client demands grow.

Client Experience

Top firms are judged increasingly on how they treat clients, not just technical output. That means:

• Faster response times

• Proactive communication

• Transparent reporting

• Advisory-led relationships

The Top 20 Accounting Firms in the US

1. Corient Business Solutions

A trusted outsourcing partner for US CPA firms and accounting practices, offering outsourced accounting and bookkeeping, payroll, tax preparation support, financial reporting & analysis, CFO and business advisory services, and back-office support. Corient operates from the US with an additional UK office and holds ISO 27001 and Cyber Essentials certifications, along with US data-protection compliance, multi-factor authentication, and end-to-end encryption.
Best for: CPA firms seeking scalable outsourcing, payroll, bookkeeping, and compliance support.

2. Deloitte

The largest accounting firm in the world by revenue and headcount, serving multinational corporations with audit, tax, risk advisory, and consulting.
Best for: Large corporations needing audit and advisory at scale.

3. PwC

Runs one of the largest audit practices among the Big Four, serving most Fortune 500 companies with audit, tax, deals, and digital transformation advisory.
Best for: Large corporations needing audit services and M&A advisory.

4. EY

Known for its focus on innovation, sustainability, and entrepreneurship across audit, tax, and consulting.
Best for: Fast-growing organizations undergoing digital or ESG transformation.

5. KPMG

The smallest Big Four firm by US revenue, with particular strength in regulated industries like financial services, energy, and infrastructure.
Best for: Regulated industries needing specialized audit and advisory expertise.

6. RSM US LLP

The largest firm outside the Big Four, focused on middle-market businesses that have outgrown a local CPA firm.
Best for: Middle-market businesses in manufacturing, real estate, healthcare, and tech.

7. BDO USA

Combines national scale with personalized service, particularly for retail, nonprofit, and financial services clients.
Best for: Mid-sized businesses wanting a balance of scale and customization.

8. Grant Thornton LLP

Offers national scale and broad advisory capability while remaining more accessible than the largest firms.
Best for: Private companies and nonprofits wanting senior-level attention.

9. Forvis Mazars

Formed through the BKD–Dixon Hughes Goodman merger and later combination with Mazars, now ranking among the US top 10 firms.
Best for: Mid-market and growth-stage businesses needing full-service assurance and tax support.

10. CBIZ

Combined with attest partner Mayer Hoffman McCann and having absorbed Marcum, CBIZ is a top-tier national provider of accounting, tax, and advisory services.
Best for: Businesses wanting integrated accounting, benefits, and advisory services.

11. Baker Tilly

Grown rapidly through acquisitions, with increasing investment in AI-driven capabilities.
Best for: Growing businesses across a broad range of industries.

12. Crowe LLP

A leading audit, tax, advisory, and consulting firm with specialist strength in assurance, corporate tax, and risk consulting.
Best for: Businesses needing audit and consulting expertise across sectors.

13. Moss Adams

Known for deep industry specialization and a strong West Coast presence.
Best for: Privately held and middle-market businesses, particularly on the West Coast.

14. CohnReznick

Particular strength in real estate, technology, and government contracting.
Best for: Real estate, tech, and government-contracting businesses.

15. Plante Moran

Consistently ranked among the best firms to work for, with a strong Midwest presence.
Best for: Privately held businesses and nonprofits seeking a full-service regional partner.

16. PKF O'Connor Davies

A top-tier national firm with particular strength in nonprofit and employee benefit plan audits.
Best for: Nonprofits, healthcare organizations, and benefit plan sponsors.

17. Withum

Combines national scale with an entrepreneurial, tech-forward culture.
Best for: Tech-forward businesses and startups needing scalable advisory support.

18. Eide Bailly

A top-tier regional firm with strength across the central US.
Best for: Businesses across the central US seeking full-service regional support.

19. Wipfli

Strong focus on technology-enabled advisory and industry-specific solutions.
Best for: Businesses seeking tech-enabled advisory and outsourced accounting support.

20. Cherry Bekaert

A fast-growing national firm with strength in government contracting, manufacturing, and private equity-backed businesses.
Best for: PE-backed businesses and government contractors.

Top 20 US Accounting Firms: Quick Comparison

Services Leading US Accounting Firms Now Offer

Audit and Assurance

Financial statement audits, internal audits, risk assessments, and regulatory compliance reviews.

Tax Advisory

Corporate tax, state and local tax (SALT) planning, international tax, R&D tax credits, and capital gains tax strategy.

Bookkeeping and Outsourcing

Bookkeeping, payroll, accounts payable/receivable, and management accounts — increasingly outsourced to scale without added staffing pressure.

Payroll Services

Federal and state payroll tax processing, 401(k) and benefits administration, W-2/1099 compliance, and multi-state payroll reporting.

Advisory Services

Cash flow planning, business strategy, M&A support, financial forecasting, and digital transformation guidance.

Trends Shaping US Accounting Firms in 2026

AI-Powered Accounting

AI is automating invoice processing, data entry, reconciliations, fraud detection, and financial reporting. Practices that have invested in training teams and operating AI in accounting and finance workflows have been able to cut operational costs considerably.

Growing Demand for Outsourcing

Rising compliance workloads and persistent talent shortages are pushing firms toward outsourcing partners for white-label bookkeeping, sales tax support, payroll, year-end reporting, and audit support.

IRS Digital Reporting Requirements

Firms must maintain digital records, automated reporting systems, and IRS e-filing-compatible software — fueling demand for cloud accounting expertise.

Private Equity Investment

PE investment continues funding technology upgrades, acquisitions, talent recruitment, and geographic expansion, especially among mid-market firms like CBIZ and Baker Tilly.

Cloud Accounting Growth

Tools like QuickBooks, Xero, and Sage are driving improvements in collaboration, reporting visibility, compliance management, and workflow efficiency.

Frequently Asked Questions

What's the difference between accounting outsourcing and traditional accounting?
Traditional accounting relies on internal teams for bookkeeping, payroll, compliance, and reporting. Outsourcing delegates some or all of these functions to an external provider while the business retains oversight — typically to improve scalability and cost control.

How much do US accounting firms typically charge?
Fees vary by scope, size, and complexity. Typical ranges: bookkeeping ($150–$1,500+ monthly), payroll ($6–$20 per employee), year-end reporting ($750–$7,500+), and project-based tax advisory pricing.

How do top firms integrate technology into their workflow?
Leading firms use cloud accounting software, AI-powered automation, digital audit tools, workflow management systems, and business intelligence dashboards for faster, more accurate reporting.

How many CPA and accounting firms are there in the US?
An estimated 45,000+ CPA firms operate in the US, with most being small local practices of four or fewer employees.

Final Thoughts

The list of top US accounting firms isn't static,  it shifts as firms invest in technology, automation, cloud accounting, outsourcing, and advisory capability. Meanwhile, compliance demands, talent shortages, and rising client expectations are pressuring firms of every size, making scalable support models increasingly essential.

By pairing internal expertise with outsourcing partners such as Corient Business Solutions, US accounting practices can expand capacity, improve efficiency, and focus on higher-value advisory work — without overwhelming their teams. The firms leading the industry tomorrow are the ones already balancing technology, people, and scalability today. Want to do everything right in accounting outsourcing? Contact us and see it for yourself.

About the Author

This article is brought to you by Corient Business Solutions, a US-focused outsourcing partner helping CPA firms and accounting practices scale through bookkeeping, payroll, tax preparation support, financial reporting, and CFO advisory services. Learn more at corientbs.com.