With a competitive and dynamically changing business environment, the success of your company’s finances can be made or broken depending on the accounting partner you settle on. It could be working with complex tax laws, conducting precise audits, or improving business financial efficiency; it requires companies that will not just comply but also offer insight, strategy, and value. The market has traditionally been dominated by the Big 4 accounting firms, with their extensive knowledge and international reach.

Nevertheless, there is a significant change in 2025. With the increasing number of businesses and mid-market companies, they are now considering mid-tier accounting firms that offer Big Four professionalism, greater flexibility, and individual client relationships. These companies unite international competencies with regional knowledge and will be recommended to business ventures that require a balance between pricing and talent.

This post delves further into what makes up a mid-tier firm, the top mid-tier accounting firms of 2025, and helps you compare the two with the Big 4 to determine the best company that meets your company’s requirements.

What Defines a Mid-Tier Accounting Firm?

The term mid-tier accounting firm in the accounting ecology refers to the world-renowned accounting firms that lie between small, localized accounting firms and the Big 4 accounting firms (Deloitte, PwC, EY, and KPMG). These companies are known to have a wide range of clientele, including small- to mid-sized companies, start-ups, and local corporations, for which they provide services such as audits, tax reporting, financial advice, and advisory services.

Compared to the Big 4, mid-sized accounting firms tend to focus on personal interaction, quicker decision-making, and custom solutions. They possess a well-structured international operations system that ensures their clients have global experience and local insight. For example, companies like RSM, BDO, and Grant Thornton can provide services across multiple countries through their international presence.

The current business requirements are significantly changing the mid-tier accounting firms to cope with prevailing demands. They are going to drive digital change, implement powerful cloud-based accounting software, and improve their advisory capabilities beyond bookkeeping. More and more companies are taking sustainability reporting, cybersecurity, and AI-based analytics into account, enabling their clients to make more intelligent, data-driven decisions.

Basically, mid-tier companies sit between local availability and global accessibility—they offer quality financial services without the high fees of the Big 4.

Top Mid-Tier Accounting Firms in 2025

Due to increased flexibility, relationship-based, and cost-effective accounting opportunities offered by sources outside the Big 4, mid-tier accounting firms are becoming reliable partners to both global and mid-market enterprises. These companies offer a comprehensive range of audit, tax, and advisory services, with a strong focus on personal service —a quality most growing firms cherish.

Here is a glimpse of the top mid-tier accounting firm in 2025, known worldwide for its innovation, skill, and strategic mindset.

BDO – Global Advisory Strength and Mid-Market Focus

Best For	Mid-market and multinational companies seeking integrated tax, audit, and advisory services.
Key Features	Operates in 160+ countries; expertise in digital transformation, sustainability consulting, and cross-border compliance.
Global Presence	1,800+ offices worldwide with a focus on emerging and developed markets alike.
Notable Strengths	Personalized client service with Big 4-level technical depth; strong reputation among mid-tier accounting firms globally.

As a global company, BDO is a major mid-tier accounting firm with over 160 offices worldwide. The company pays close attention to clients, who are middle-market corporations that require assistance from the Big 4 without the bureaucracy. BDO has three primary sources of strength — audit, tax, and business advisory — supported by innovative digital technology and automation. This is achieved by its desire to learn clients’ business models so it can provide solutions that are efficient and profitable in the short and long term. BDO’s emphasis on digital transformation and sustainability consulting will ensure the company becomes one of the preferred partners of progressive enterprises in 2025.

Aone Outsourcing – Global Accounting Efficiency & End-to-End Support

Best For	Businesses seeking reliable and scalable outsourced accounting, bookkeeping, and financial reporting solutions.
Key Features	End-to-end accounting support, cloud integration (Xero, QuickBooks, NetSuite), secure data handling, and real-time financial visibility.
Global Presence	Serving clients across the US, UK, Australia, and Asia with dedicated regional teams.
Notable Strengths	Combines mid-tier expertise with outsourcing efficiency — delivering accurate, affordable, and growth-focused accounting services.

Aone Outsourcing has quickly become a trusted partner to organizations seeking scalable, technologically oriented accounting solutions. With a full-time team of virtual bookkeepers, tax professionals, and financial analysts, Aone offers end-to-end services, including transaction management, payroll services, and financial reporting, as well as financial advice. The unique feature of Aone compared to other mid-tier accounting firms is its personalized vision, open communication, and connectivity with popular cloud-based tools such as Xero, QuickBooks, and NetSuite. By combining flexibility in outsourcing, SMEs, startups, and international enterprises can ensure that they are accurate, cost-efficient, and expand at a pace they are comfortable with.

Grant Thornton – Tech-Driven SME Accounting

Best For	Growing businesses and SMEs seeking modern, cloud-based accounting and advisory solutions.
Key Features	Emphasis on automation, sustainability, and AI-driven business insights.
Global Presence	140+ countries with regional expertise across Europe, Asia-Pacific, and the Americas.
Notable Strengths	Combines innovation with human-led advisory; known for tech-driven approaches among mid-size accounting firms.

One of Grant Thornton’s strengths is its innovation-based strategy and strong knowledge of small and medium-sized businesses. The company operates in more than 140 markets; it incorporates technology, data analytics, and sustainability into its audit and advisory services. Grant Thornton has the advantage of combining technical skills with nimble customer service, enabling businesses to respond quickly to dynamic market conditions. Its focus on cloud accounting, ESG reporting, and strategic advisory, which have persisted in 2025, positions it among the most trusted mid-sized accounting firms worldwide.

RSM Global – Powerful in Audit and Assurance

Best For	Mid-tier enterprises looking for top-tier audit and assurance expertise.
Key Features	Robust audit frameworks, risk advisory, and corporate governance consulting.
Global Presence	Offices in 120+ countries serving middle-market clients worldwide.
Notable Strengths	Ranked among the leading mid-tier accounting firms with deep audit specialization.

RSM Global is one of the leading mid-tier accounting firms globally, renowned for its audit and assurance services. With a presence in over 120 countries, RSM serves a large number of mid-market clients seeking high-quality audit processes and compliance management services. The firm’s advisors make evidence-based projections that go beyond financial statements, helping businesses enhance governance and transparency. The client-first model at RSM, coupled with expertise in risk advisory and performance improvement, positions the company as a reliable global accounting leader in 2025.

Crowe Global – Customized Tax and Consulting

Best For	Businesses need personalized tax, risk, and consulting services.
Key Features	Industry-specific strategies, strong client relationships, and flexible service models.
Global Presence	150+ countries with a focus on North America, Europe, and Asia-Pacific.
Notable Strengths	Recognized for building long-term partnerships and adaptability among mid-tier accounting firms.

Crowe Global is a company that conducts its business through over 200 member firms worldwide and provides customized tax, audit, and consulting services. In contrast to larger accounting networks, Crowe believes in building strong relationships with clients and developing solutions to each business’s specific problems. It has professionals with extensive experience in the manufacturing, healthcare, and financial services industries. As one of the finest mid-tier accounting firms in 2025, Crowe’s localized knowledge and tax planning expertise enable middle-tier clients to navigate complex regulatory landscapes with confidence.

Baker Tilly – Industry-Specific Advisory

Best For	Family-owned and sector-specific businesses seeking holistic advisory and audit support.
Key Features	Industry expertise across healthcare, manufacturing, and technology.
Global Presence	145 territories with strong representation in the U.S., Europe, and Asia.
Notable Strengths	Strategic consulting approach and commitment to mid-market growth.

Baker Tilly’s unconventional approach is to combine traditional accounting services with industry-targeted advisory services. The company is well distributed across 140+ countries, serving business retail, real estate, energy, and technology.  Its consultants are known for their intimate knowledge of family-owned and mid-sized companies and offer services that facilitate succession planning, expansion, and operational change. Baker Tilly will remain in the mid-tier space in 2025 through its progressive orientation towards strategy, innovation, and digital advisory.

Mazars – Compliance and Risk Excellence

Best For	Corporations seek a balance between compliance, ethics, and innovation.
Key Features	Expertise in audit, tax, financial advisory, and risk management.
Global Presence	100+ countries with a strong presence across Europe and Africa.
Notable Strengths	Globally integrated firm structure ensures transparency and consistency.

Mazars is a mid-tier accounting firm worldwide with a strong track record in compliance, audit quality, and risk management. It works in more than 100 countries, providing independent advisory services with a highly collaborative approach to clients. In specific areas important in the dynamic business environment of 2025, Mazars excels in integrated reporting, corporate governance, and sustainability compliance. Its experience in integrating global standards with local regulatory expertise makes it the first choice for multinational SMEs and socially responsible organizations.

PKF International – Regional Accounting Leader

Best For	Regional and cross-border firms requiring agile accounting and tax services.
Key Features	Emphasis on regional expertise and local responsiveness.
Global Presence	Over 150 member firms across 125 countries.
Notable Strengths	Blends local insight with global reach — a leading mid-tier accounting company.

PKF International has positioned itself as a market leader among mid-sized accounting firms, especially in regional and emerging markets. PKF operates in 150+ countries and provides agile accounting, audit, and tax compliance services for growing companies. It has a competitive advantage in its localized knowledge base and agility, enabling the client to more easily find solutions to regulatory challenges. By 2025, PKF would still be renowned for providing value-oriented services and cultivating sustainable relationships with its clients through open communication and creativity.

Moore Global – Cross-Border Financial Expertise

Best For	Businesses are expanding internationally and managing complex financial structures.
Key Features	Strong in international taxation, audit, and advisory.
Global Presence	110+ countries with 30,000+ professionals.
Notable Strengths	Focused on collaboration and cross-border business growth.

Moore Global is an entity that serves businesses with cross-border financial needs in more than 110+ countries. The company is exceptionally reputable in international tax planning, transfer pricing, and global business advisory. The agile form of Moore enables it to provide responsive service to its clients as it moves into new markets. As globalization shapes business strategies in 2025, Moore’s ability to combine local knowledge with international compliance standards will make it a frontrunner among mid-tier accounting firms worldwide.

Nexia International – Promised Mid-Market Clients

Best For	Entrepreneurial and growing businesses require scalable accounting solutions.
Key Features	Specializes in tax, audit, and business advisory services integrated with cloud platforms.
Global Presence	125+ countries, 250+ member firms worldwide.
Notable Strengths	Known for proactive guidance and strong SME relationships.

Nexia International specializes in working with entrepreneurial and middle-market companies that require financial counseling with a growth orientation. With a workforce of more than 5000 employees, Nexia operates in more than 120 countries, offering tax, audit, and advisory services to dynamic businesspersons. It has a progressive mindset that combines technology and data analytics to enhance clients’ decision-making. In 2025, Nexia will focus on active communication, transparency, and innovation, strengthening the company’s position as a leader among the top mid-tier accounting firms serving emerging businesses.

Pitcher Partners (Australia) – Domestic Experience

Best For	SMEs and growing businesses in Australia are seeking trusted financial partners.
Key Features	Tailored business advice, tax planning, and compliance support.
Global Presence	National strength with local offices across major Australian cities.
Notable Strengths	Deep understanding of local market challenges and opportunities.

One of the most reputable regional mid-tier firms in Australia (Pitcher Partners) is characterized by a strong local presence and accounting support for SMEs. The company focuses on mid-sized and family-owned businesses, offering tax planning, business advisory services, and audit services. It also has the advantage of extensive knowledge of regional market forces, enabling it to provide practical, results-oriented advice. This company remains a symbol of the heart of local expertise in the global mid-tier accounting network in 2025.

Whether it is on an international level, like BDO, or in the scope of compliance superiority at Mazars, or in technological innovation at Grant Thornton, these mid-range companies are the new generation of global accounting. They represent the ideal combination of accessibility, innovation, and strategic positioning —they show that the Big 4 are no longer the sole providers of revelation to businesses in delivering world-class financial management.

How to Choose the Right Mid-Tier Firm for Your Business?

Selecting the right accounting partner is an important decision that shapes your company’s financial stability and growth. When measuring mid-sized accounting firms, companies must not rely solely on brand name but also on their practical fit in the real world, including expertise, responsiveness, and innovation.

Here’s what to look for:

Industry Specialization

Select a company that is aware of the financial environment of your industry. Mid-tier accounting firms that focus and have specialized knowledge can provide more actionable information and compliance assurance, no matter the field—manufacturing, technology, or retail.

Global vs Regional Presence

Assuming that your business has boundaries, collaborate with a company that has an international network and local presence. Regional mid-level accounting firms have been known to offer quicker, relationship-based services than large corporate firms.

Cost vs Expertise

Mid-tier companies usually offer Big 4-level skills at affordable prices. Consider pricing arrangements that ensure you get what you deserve without compromising quality.

Advisory Support and Communication

Find companies that emphasize open communication and aggressive business consulting, but not year-end auditing. Partnerships created by relationship-oriented firms are what lead to long-term success.

Technology Adoption

Accounting today relies on automation, artificial intelligence, and cloud computing. Prefer companies that are technology adopters, are precise and transparent, and offer real-time financial visibility.

Mid-Tier Firms vs Big 4: Which Fits Your Business Needs?

The war between the Big Four and Mid-Tier Accounting Firms remains dynamic in 2025. They both fit different market segments; however, the one that suits you best will depend on the company’s size and budget, as well as your growth expectations.

Here’s a quick comparison:

Criteria	Big 4 Firms	Mid-Tier Firms
Client Size	Large multinational corporations	SMEs, startups, and mid-market enterprises
Pricing	High and premium	Moderate, with flexible engagement models
Personalization	Structured, less client-focused	Highly personalized and relationship-driven
Decision Speed	Slower due to hierarchy	Faster and more adaptable
Innovation	Big tech investments	Agile, tech-savvy adoption for practical use
Advisory Access	Limited to smaller clients	Direct and ongoing access to senior advisors
Service Breadth	Extensive, but standardized	Tailored, scalable, and industry-specific

The strengths of both of these kinds of firms are undeniable.

• The Big Four firms are prestigious, with global reach and significant scale—perfect for multinational organizations with complex business activities.

• Intermediate-level companies, however, integrate technical excellence, flexibility, cost-effectiveness, and personalized care, and are therefore more likely to grow in growing and middle-level enterprises.

Finally, it is up to your company’s structure, expectations, and collaboration needs to determine the best option.  In 2025, a middle-tier accounting firm would be the most strategic ally to you if you appreciate agility, transparency, and close advisory support.

Final Thought!

Given the evolving financial landscape, mid-tier accounting firms are redefining how businesses acquire professional accounting and advisory services. They fill the gap between small local companies and the Big 4—with global experience, personalization, and attributable value.

Although both Big 4 and mid-tier firms are worthy, the decision should be based on your company’s goals, complexity, and expectations for the collaboration.

Aone Outsourcing collaborates with businesses worldwide by matching them with reputable mid-tier accounting firms to help secure financial accuracy, scale, and sustainable growth. No matter where you are going to increase your activity —whether in the global or local market —the right partner can change your financial performance.

FAQs

Q1. Who are the top mid-tier accounting firms in 2025?

The top companies are BDO, Aone Outsourcing, RSM, Grant Thornton, Crowe Global, Mazars, and Baker Tilly, renowned for their global coverage and success in the middle market.

Q2. Why should a business choose a mid-tier accounting firm instead of a Big Four firm?

Mid-level companies are economical, provide immediate partner access, and are more personalized, making them a good fit for SMEs and growth-oriented companies.

Q3. How do I select the right mid-tier accounting firm for my business?

Analyze their experience in the industry they are operating, geographical coverage, application of technology, and quality of relationship to clients before making a decision.

Q4. Are mid-tier accounting firms suitable for international businesses? 

Yes. They are best suited to international business because most of them have cross-border compliance and extensive global networks.