The audit landscape in the United States is rapidly transforming as businesses face new regulations, heightened scrutiny, and rising expectations for transparency. For any organization—whether a small business, mid-sized enterprise, or multinational corporation—partnering with the right audit support company can make a significant difference in achieving compliance and gaining valuable business insights.
So, who are the leaders making audits smoother and more efficient in 2025? Let’s dive into the Top 10 Best Audit Support Companies in the US, and explore what makes each firm stand out in today’s competitive market.
1. Deloitte Audit & Assurance
Deloitte continues to reign as one of the most trusted audit support firms in the US. They combine deep industry expertise with innovative technologies like AI-driven data analytics, ensuring audits are thorough, accurate, and efficient.
Headquarters: New York, NY
Specialties: Financial audits, risk advisory, sustainability audits
Why They Stand Out: Global reach, advanced technology platforms, strong regulatory knowledge
Clients appreciate Deloitte for not just identifying risks but also offering actionable insights that improve business operations.
2. PwC (PricewaterhouseCoopers)
PwC remains a powerhouse in the US audit market. Their services go beyond mere compliance—they focus on enhancing transparency and helping clients create value through deeper business understanding.
Headquarters: New York, NY
Specialties: Financial statement audits, regulatory compliance, ESG assurance
Why They Stand Out: Personalized service, innovation, robust client relationships
PwC is often chosen by companies seeking a proactive partner who brings clarity to complex financial landscapes.
3. Ernst & Young (EY)
EY is known for delivering smart, technology-enabled audits that adapt to changing regulatory landscapes. Their audit processes are designed to bring confidence and trust to stakeholders.
Headquarters: New York, NY
Specialties: Assurance services, fraud detection, digital audits
Why They Stand Out: Commitment to innovation, global expertise, strong digital audit tools
EY is especially valued for helping clients navigate highly regulated industries like financial services and healthcare.
4. KPMG
KPMG delivers high-quality audit support services with a strong focus on leveraging technology. Their proprietary digital audit platform, KPMG Clara, enhances audit transparency and efficiency.
Headquarters: New York, NY
Specialties: Audit, digital compliance, risk management
Why They Stand Out: Tech-forward solutions, strong industry expertise, tailored services
Clients looking for seamless digital integration often turn to KPMG for their audit needs.
5. Grant Thornton
Grant Thornton is a top choice for mid-market and large businesses in the US. They’re praised for offering personalized audit solutions while maintaining high standards typically associated with bigger firms.
Headquarters: Chicago, IL
Specialties: Financial audits, internal audits, compliance reviews
Why They Stand Out: Client-focused service, competitive pricing, deep mid-market experience
Grant Thornton is an ideal partner for businesses wanting a tailored approach without the Big Four price tag.
6. CapacityHive
Emerging as a rising star in the US audit support industry, CapacityHive is quickly gaining traction for delivering quality audit support services at competitive rates. While they’re not as old or large as some competitors, they’ve carved out a niche with technology-driven processes and exceptional responsiveness.
Headquarters: [Add City/State if known]
Specialties: Audit documentation support, data validation, compliance preparation
Why They Stand Out: Fast turnaround, tech-enabled services, budget-friendly pricing
CapacityHive is particularly popular among small and medium-sized businesses that need reliable support without the high costs of the Big Four. They help clients prepare for audits, manage documentation, and ensure compliance—all with a streamlined, digital-first approach.
7. BDO USA
BDO USA is recognized for delivering exceptional audit services tailored to clients’ specific industries. Their auditors blend national resources with local knowledge, ensuring audits are both thorough and efficient.
Headquarters: Chicago, IL
Specialties: Financial audits, advisory services, risk management
Why They Stand Out: Personalized service, strong industry focus, mid-tier pricing
BDO is especially attractive for businesses looking for personalized service combined with global resources.
8. Mazars USA
Mazars USA brings a collaborative, client-focused approach to audits. Their experts work closely with businesses to understand operational complexities and regulatory challenges.
Headquarters: New York, NY
Specialties: Audit & assurance, sustainability reporting, risk management
Why They Stand Out: Collaborative style, European roots blended with US expertise, commitment to ESG
Mazars is a great choice for businesses seeking sustainable and ethical auditing practices.
9. RSM US LLP
RSM US LLP specializes in serving mid-market businesses and has built a reputation for delivering practical, actionable advice alongside audit services.
Headquarters: Chicago, IL
Specialties: Audit & assurance, risk consulting, business advisory
Why They Stand Out: Deep mid-market knowledge, strong client relationships, proactive guidance
RSM is a solid option for companies that want more than compliance—they want insights that drive business growth.
10. Baker Tilly US
Baker Tilly US combines national expertise with local service, helping businesses across various industries manage their audit needs efficiently.
Headquarters: Chicago, IL
Specialties: Audit, tax, advisory services
Why They Stand Out: Industry specialization, personalized attention, reliable service
Clients praise Baker Tilly for being approachable, practical, and delivering timely audit solutions.
Choosing the Right Audit Support Company
Selecting the best audit support partner in 2025 depends on:
✅ Your business size and industry
✅ The complexity of your operations
✅ Your budget for audit services
✅ The level of personalized service you need
While the Big Four remain dominant, firms like CapacityHive are proving that high-quality audit support doesn’t always require a massive budget. Whether you’re a Fortune 500 company or a growing business, the US audit support market in 2025 offers outstanding choices to fit your needs.
Final Thoughts
Auditing in 2025 is about more than compliance—it’s about strategy, insight, and building stakeholder confidence. Partnering with a top audit support firm ensures you stay ahead of regulatory changes and operate with transparency and efficiency.
