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To operate any size of business or industry, a trustworthy and professional accounting service is not negotiable. A financial company does not just balance your books. The right partner will help with tax planning, financial projections, compliance, mergers, acquisitions, and even lead you through an international expansion. A wise decision can be the key to successful development, while poor choices can result in failure.
The difficulty, however, lies in the numerous options available. In the United States, there are hundreds of companies that claim to be the best accounting firms. For a small business owner in New York, a real estate investor in Miami, or a global company in California, the accounting partner can make or break it. Collaborating with an inappropriate company can result in expensive penalties, poor accounting, or missed growth opportunities.
The blog provides information about the most successful accounting companies in the USA, including not only the international giants of the Big Four but also the well-established mid-sized and local companies. We will also break down the services these firms offer and give you practical suggestions on how to select the accounting firm that works for you, so you can make a decision that is grounded in facts, not guesses.
Best Accounting Firms in the USA: 2026 Comparison Table
| Firm | Best For | Headquarters | Firm Type | Known For |
| Deloitte | Large & multinational enterprises | New York, NY | Big Four | Tech consulting, digital transformation |
| Pwc | Fortune 500 audit & assurance | New York, NY | Big Four | Audit rigor, investor trust |
| EY | Innovation-focused & high-growth companies | New York, NY | Big Four | Startup advisory, sustainability |
| KPMG | Regulated industries | New York, NY | Big Four | Regulatory & risk advisory |
| RSM US LLP | Middle-market businesses | Chicago, IL | National mid-tier | High-touch client relationships |
| BDO USA, LLP | Big-firm resources, regional service | Chicago, IL | National mid-tier | 65+ US offices, global network |
| Grant Thornton LLP | Mid-to-large Big Four alternative | Chicago, IL | National mid-tier | Practical, innovation-focused advisory |
| CBIZ & MHM | Small-to-mid, outsourcing-friendly | Cleveland, OH | Regional/boutique | Flexible outsourcing solutions |
| Baker Tilly US, LLP | Construction, real estate, financial services | Chicago, IL | Regional/boutique | Niche industry expertise |
| Moss Adams LLP | West Coast startups & family-owned businesses | Seattle, WA | Regional/boutique | Tech, healthcare, relationship-driven |
What Type of Accounting Firm Fits Your Business?
It’s important to know which type of firm you need before you compare individual firms:
Big Four (Deloitte, PwC, EY, KPMG): Best for large, complex, or multi-national companies that require the SEC-level audit rigor, cross-border tax expertise, or investor and lender credibility that only a Big Four name can bring.
National mid-tier firms (RSM, BDO, Grant Thornton): Mid-tier firms (Sprint, KPMG, Ernst & Young, Grant Thornton, RSM, BDO) – typically best suited to more established middle-market companies seeking Big Four-level skills at more affordable rates and a more personalized experience with their client.
Regional and boutique firms (Baker Tilly, Moss Adams, CBIZ): Regional or Boutique firms (Baker Tilly, Moss Adams, CBIZ) – a good match for companies that are more industry specific (construction, tech, healthcare), more family owned, or more startup oriented, where a closer, more focused partnership outweighs the need for global size.
Regional and boutique firms (Baker Tilly, Moss Adams, CBIZ): For small businesses and start-ups that require regular, professional bookkeeping, payroll, tax preparation, and CFO-level analysis without the expense of a traditional accounting firm, outsourced accounting partners are the perfect solution. Refer to the special section below.
The 10 Best Accounting Firms in the USA
Whenever individuals need the best accounting firms in the US, the Big Four are usually the order of the day. Deloitte, PwC, EY, and KPMG are the four international companies that are leaders in their industry and have a representation in almost all major markets. They are leaders in terms of global networks, a multi-industry knowledge base, and expertise in handling the most complex accounting and consulting tasks.
Nevertheless, they are not the only competitors. Several mid-sized and regionally based firms are among the largest accounting firms in the US, and are, in fact, the better choice for many businesses.
1. Deloitte
Headquarters: New York, NY | Firm Type: Big Four | Best fit: Large & multinational enterprises
The reason why they stood out: Deloitte is ranked first as the largest accounting firm in the United States and the world. Their service offerings are audit, tax, consulting, risk advisory and financial advisory. Technology consulting is also one of the areas in which Deloitte excels, as well as a leader in digital business transformation. When automating, moving to the cloud, or using AI-powered analytics, Deloitte is usually a preferred partner to reach.
2. PricewaterhouseCoopers (PwC)
Headquarters: New York, NY | Firm Type: Big Four | Best fit: Fortune 500 audit & assurance
Reasons why they Sparkle: PwC enjoys a good reputation for auditing and consulting services. They have great experience working with Fortune 500 companies and are highly respected in the fields of healthcare, finance, and government. PwC also emphasises trust and transparency in reporting and is hence a favourite among companies that would like to enhance investor relations.
3. Ernst & Young (EY)
Headquarters: New York, NY | Firm Type: Big Four | Best fit: Innovation-focused & high-growth companies
Why They Are Unique: EY has a high emphasis on innovation, sustainability, and entrepreneurship. Their consulting division assists companies with matters ranging from cybersecurity to international tax restructuring. They also invest heavily in backing start-ups and entrepreneurs, which makes them appealing to rapidly growing businesses that need prompt advisory services.
4. KPMG
Headquarters: New York, NY | Firm Type: Big Four | Best fit: Regulated industries (energy, infrastructure, financial services)
What Makes Them Different: KPMG is the smallest among the Big Four yet one of the world’s leaders. It is known for audit services and also performs well in advisory services, including support for institutions in the energy, infrastructure, and financial services industries. Most companies value KPMG’s practical approach and its regulatory expertise.
5. RSM US LLP
Headquarters: Chicago, IL | Firm Type: National mid-tier | Best fit: Middle-market businesses
Why They Are Special: RSM is the most prominent accounting firm in the US that is not among the Big Four, and it has earned a reputation as the preferred accounting firm among middle-market businesses. They are also experts in audit, tax, and consulting; however, their strength lies in the long-term relationships with their clients.
RSM’s high-touch strategy implies that a business receives more personal attention than may be provided by the Big Four. They are also significant investors in industry-specific knowledge, and they assist clients in real estate, healthcare, and manufacturing to overcome the unique challenges.
6. BDO USA, LLP
Headquarters: Chicago, IL | Firm Type: National mid-tier | Best fit: Big-firm resources with regional service
Why They are Special: BDO has more than 65 offices in the country, which belong to the world network of BDO, implying that they are both domestically and globally recognised. Their services include assurance, tax, advisory and outsourcing services.
The appealing aspect of BDO is that it strikes a balance between scale and customisation, allowing companies to enjoy the benefits of a large firm in terms of resources and expertise, while also benefiting from the personalisation of a regional firm. They are particularly effective in industries such as retail, nonprofit, and financial services.
7. Grant Thornton LLP
Headquarters: Chicago, IL | Firm Type: National mid-tier | Best fit: Mid-to-large Big Four alternative
Why They Shine: Grant Thornton is a good alternative to the Big Four, especially for mid-sized to large businesses. They have a reputation for practical service and a focus on innovation in accounting practices.
They are versatile partners, with expertise that spans industries such as healthcare, manufacturing, and real estate. Another reason clients tend to refer to Grant Thornton is that it can provide a blend of technical and practical, business-friendly advice.
8. CBIZ & MHM
Headquarters: Cleveland, OH | Firm Type: Regional/boutique | Best fit: Small-to-mid businesses, outsourcing-friendly
Why They Stand Out: CBIZ and MHM (Mayer Hoffman McCann) are well-known companies that specialise in providing flexible and cost-effective solutions for small and mid-sized firms. They offer accounting, tax, and advisory services.
However, the information they are most familiar with is their outsourcing solutions, which are perfect for businesses that want to concentrate on growth without a large in-house finance department. Their auditing and consulting hybrid model enables companies to simplify operations without going astray.
9. Baker Tilly US, LLP
Headquarters: Chicago, IL | Firm Type: Regional/boutique | Best fit: Construction, real estate & financial services
Why They Are Special: Baker Tilly has a strong regional presence, complemented by international coverage through Baker Tilly International. They provide tax, assurance, and consulting services; however, they are known for niche expertise in the construction, real estate, and financial services sectors. Baker Tilly is a good option for businesses that require highly skilled expertise with international capabilities.
10. Moss Adams LLP
Headquarters: Seattle, WA | Firm Type: Regional/boutique | Best fit: West Coast startups & family-owned businesses
Reasons They Are Different: Moss Adams has a powerful reputation on the West Coast, established in the technology, healthcare, and manufacturing industries. They are famous for working with growing startups, family-owned businesses, and companies that want a partner skilled in technical issues but also takes a relationship-based approach.
Moss Adams also focuses on advising clients regarding innovation and upcoming trends in the industry, which makes them not only future-oriented but also reliable at the moment.
What Leading Accounting Firms Offer: Key Services Explained
The best accounting companies do not perform taxes as if they were doing it for themselves. They are full-service business partners. In the meantime, this is generally what they offer:
- Audit and Assurance – The financial statements, regulations, and increased credibility towards investors or lenders. For public companies, compliance with SEC or global reporting requirements is a requirement.
- Tax Advisory/Compliance – Since the federal income tax, including international transfer pricing, companies reduce the amount of taxes owed and remain in compliance. This is especially beneficial for growing companies that must operate across several states or international jurisdictions.
- Consulting & Advisory – Beyond numbers, companies can offer businesses expert advice on strategy, mergers and acquisitions (M&A), technology adoption, and cybersecurity. Most businesses consider such services as the actual value-add to the basic bookkeeping.
- Risk and Compliance Management – Companies assist organisations in managing the changing regulations (think: Sarbanes-Oxley, GDPR, ESG reporting). In the case of industries such as banking or healthcare, this is a guarantee of survival in a highly regulated world.
- Outsourced Accounting/Payroll- This is becoming increasingly popular as many mid-sized firms desire the services of a leading firm without developing a comprehensive in-house financial department.
How to Choose the Right Accounting Firm for Your Business
There are too many large names and special players, and it may seem easier to select the correct firm. Here’s a practical checklist:
Size and Fit: A start-up might not require a Big Four company (and its associated costs). Smaller middle-tier firms such as RSM or Grant Thornton tend to be more personable.
Experience in the Industry: Find companies with inside knowledge of your industry. Moss Adams is a good example of a company excelling in tech and healthcare, whereas Baker Tilly is more experienced in construction and financial services.
Scope of Services: In case you only require annual filing of tax filing, a smaller firm could be used. However, when it comes to advisory, risk management, or overseas expansion, choose companies that offer more services.
Technology & Tools: Inquire about what software platforms the company operates in – cloud accounting, automation, and AI-driven insights are the new standards in the industry. A company lagging in technology can reduce its expansion.
Budget & Value: Bigger does not necessarily mean better. Balance the price and value you are receiving, particularly in long-term advisory and consulting services.
Pro tip: Compare firms not just on tax prep, but on consulting, risk management, and outsourcing support: these become significant as your business grows.
How to Choose the Right Accounting Firm for Your Business
There are too many large names and special players, and it may seem easier to select the correct firm. Here’s a practical checklist:
- Size and Fit: A start-up might not require a Big Four company (and its associated costs). Smaller middle-tier firms such as RSM or Grant Thornton tend to be more personable.
- Experience in the Industry: Find companies with inside knowledge of your industry. Moss Adams is a good example of a company excelling in tech and healthcare, whereas Baker Tilly is more experienced in construction and financial services.
- Scope of Services: In case you only require annual filing of tax filing, a smaller firm could be used. However, when it comes to advisory, risk management, or overseas expansion, choose companies that offer more services.
- Technology & Tools: Inquire about what software platforms the company operates in – cloud accounting, automation, and AI-driven insights are the new standards in the industry. A company lagging in technology can reduce its expansion.
- Budget & Value: Bigger does not necessarily mean better. Balance the price and value you are receiving, particularly in long-term advisory and consulting services.
Pro Tip: Before contracting with a firm, ask for case studies or references from clients of a similar size. It is the most effective method for estimating whether they will secure your business.
Do You Know? Most Small Businesses Don’t Need a Big Four Firm…
See what an outsourced accounting partner can take off your plate instead.
When an Outsourced Accounting Partner Makes More Sense Than a Big Four Firm
For most small and mid-sized businesses, a Big Four engagement isn’t just unnecessary, it’s the wrong tool for the job. Big Four firms are built for public-company audit complexity, multinational tax structuring, and enterprise-scale consulting. If your business doesn’t need that, you’re paying for infrastructure you’ll never use.
An outsourced accounting partner like Aone Outsourcing Solutions is built for a different job: giving growing businesses accurate books, reliable payroll, tax preparation, accounts payable and receivable support, and CFO-level advisory — delivered by a dedicated team, without the overhead of an in-house finance department or the price tag of a traditional firm.
This is typically the right fit if:
- You’re a startup or small business that needs consistent, professional bookkeeping rather than a once-a-year tax relationship.
- You’re outgrowing DIY accounting software but aren’t ready for (or don’t need) a full in-house CFO.
- You want Big-Four-level financial discipline and reporting rigor without Big Four pricing.
- You need scalable support – bookkeeping today, payroll services and AP/AR tomorrow, CFO-level insight as you grow.
Pro Tip: Before contracting with a firm, ask for case studies or references from clients of a similar size. It is the most effective method for estimating whether they will secure your business.
Wrapping Up
Choosing among the greatest accounting firms in the USA, the choice, at the end, corresponds to size of your business, industry, and long-term objectives. In the case of a multinational company or a company with very complicated structure, the Big Four companies of Deloitte, PwC, EY, and KPMG can provide the global access, profound expertise, and reputation that will open the doors and bring a sense of confidence among investors.
Nonetheless, mid-market companies like RSM, BDO, and Grant Thornton offer a viable option and their service quality is as good as that of leading firms, but the services are given in a more personalized, client-centered manner. In the case of startups, family-owned companies, and regional businesses, the companies such as Moss Adams, Baker Tilly, and CBIZ are usually the right balance between price and experience.
The key thing is to look at your accounting firm not only as a service provider but also a strategic partner. The right company will not only maintain your compliance with requirements related to tax and audit, it will also guide you through the difficulties, find the opportunity, and design the growth that will continue.
Frequently Asked Questions
Q1: What are the Big 4 accounting companies?
The Big Four are Deloitte, PwC, EY, and KPMG. For a full breakdown of their history, services, and how they compare to mid-tier firms, see our complete Big Four accounting firms guide.
Q2: What accounting firm is best for small businesses?
Small businesses will usually be better served by mid-range companies, such as RSM, BDO, or Grant Thornton, which offer a more personalised and cost-efficient service tailored to smaller companies.
Q3: What types of consulting do top accounting firms offer?
In addition to tax and audit, major companies offer consulting services in business strategy, mergers, technology adoption, risk management, and digital transformation.
Q4: How can I choose the right accounting firm?
The optimal option will be based on your size, industry, and objectives. Large companies bring international experience, whereas mid-level and local companies are often more cost-effective and offer a more personalised approach.
Q5: Why are many firms outsourcing accounting services?
Outsourcing helps companies save money, gain knowledge, and expand services on a case-by-case basis. Most leading companies also offer outsourced bookkeeping, payroll, and tax preparation services to meet this need.
Q6: How much does a top accounting firm cost for a small business?
The price of bookkeeping services can range from a few hundred dollars per month for outsourced bookkeeping to enterprise-level Big Four engagement fees.
Q7: Is a Big Four firm overkill for a small business?
In most cases, yes. Big Four firms are built for public-company audit complexity and multinational operations. Small and mid-sized businesses typically get better value and more personal service from a mid-tier, regional, or outsourced accounting partner.
Q8: What’s the difference between an accounting firm and an outsourced accounting provider?
A traditional accounting firm typically bills project-by-project (tax season, an annual audit). An outsourced accounting provider functions more like an extension of your team — handling ongoing bookkeeping, payroll, and financial reporting on a continuous basis, often at a lower total cost.
Q9: Which accounting firms specialize in audits for private or mid-sized companies?
RSM, BDO, Grant Thornton, and Baker Tilly all maintain strong private and mid-market audit practices, generally offering more accessible pricing and closer client relationships than a Big Four audit engagement.
