Facts 101: What to Know About the Big Four Accounting Firms

Even with the emerging accounting firms today, businesses still opt to rely on a reputable partner for their number crunching. For many, the Big 4 accounting firms still remain at the forefront of the best practices in the industry.  

Related: How to Select the Best Outsourced Accounting Service 

The Big 4 Accounting Firms 

The four accounting giants are formally made up of eight separate firms. After a series of mergers and dissolutions, the Big 4 were formed.  

Each of the Big 4 firms is several times the size of BDO Global, the fifth largest firm. This disparity in company size drew the line between the accounting giants and the remaining firms.  

Outsourcing your accounting and bookkeeping services to one of the Big 4 accounting firms gives your company a solid and trusted ground in operating with real-time data, which guides you in making better business decisions.  

Here’s a brief about the leading accounting names in the industry: 

1. Deloitte 

Operating in over 150 countries worldwide, Deloitte stands as the biggest among the Big 4 accounting firms. It has reported revenue of $67.2 billion generated from its four subsidiaries: Deloitte & Touche LLP, Deloitte Consulting LLP, Deloitte Financial Advisory Services LLP, and Deloitte Tax LLP. 

Deloitte provides services such as audit and assurance, consulting, financial advisory, risk advisory, tax and related services. Over the years, Deloitte merged and bought companies and established subsidiaries, making it one of the biggest names in the accounting landscape. 

2. PricewaterhouseCoopers (PwC)  

In terms of revenue, PwC comes next to Deloitte. Former corporations Price Waterhouse and Coopers & Lybrand decided to merge in 1998, which formed what we know today as PricewaterhouseCoopers.  

PwC has more than 370,000 employees in 149 countries. Its gross revenues for the year ending 30 June 2024 amounted to $55.4 billion, making them run close to the 2024 revenue of Deloitte. 

Aside from accounting and bookkeeping services, PwC also specializes in tax and advisory, IFRS reporting, and others. It serves 86% of the Global Fortune 500 companies and more than 100,000 entrepreneurial and private businesses.  

3. Ernst & Young (EY)  

Coming in third rank is E.Y., which operates in over 150 countries globally through member firms. They are structured through the Executive and Regions in four geographic areas: America; Europe, Middle East, India and Africa (EMEIA); Asia-Pacific, and Japan.  

Formerly the 4th and 5th largest accounting firms, Ernst & Whinney and Arthur Young merged in 1989 to create what we know today as Ernst and Young.  

EY also took over the global operations of Arthur Andersen, a former member of the Big 5 after its collapse in 2002. To date, EY has over 700 offices and 400,000 employees around the world who offer quality services to diverse clientele. 

4. Klynveld Peat Marwick Goerdeler (KPMG)  

Among the Big 4, KPMG is the oldest firm, with its earliest parent company being founded in 1818. In 1911, William Barclay Peat & Co merged with Marwick Mitchell & Co to form Peat Marwick.

The largest merger of this firm took place between KMG and Peat Marwick that finally established KPMG. With more than 670 offices in over 145 countries, KPMG is the only member of the Big 4 with quarters outside of London and is based in the Netherlands.  

Read: Small vs. Large Accounting Firms: Which One to Hire? 

How the Big 4 accounting firms are integrating AI 

Artificial Intelligence, or AI, refers to the simulation of human intelligence in machine that are programmed to think like humans and mimic their actions.  

In recent years, AI has become a game-changer in the finance and accounting industry, enabling firms to automate repetitive tasks, enhance decision-making, and improve overall efficiency. 

The Big Four accounting firms—Deloitte, PwC, EY, and KPMG—are at the forefront of this technological shift. Aside from how these top accounting firms operate, it's also important to understand how they are incorporating cutting-edge technologies like AI into their processes. 

Here are some ways they are integrating AI in their processes according to Daniel Fagella, head of research at Emerj.  

1. Deloitte

Deloitte uses AI in three main ways: 

a. Product:

Deloitte adds AI features to some of the tools they offer clients. For example, their CortexAI platform helps businesses manage risks and handle compliance better. It also uses AI to analyze data and give helpful insights, which makes their services even more useful.  

b. Process:

AI helps make daily work easier in Deloitte by automating tasks. For instance, they use Robotic Process Automation (RPA) to handle repetitive tasks like pulling data or matching numbers. This saves time, cuts down on errors, and lets their team focus on more important work. 

c. Insight:

Deloitte uses AI to look at large amounts of data and find useful patterns. Their Deloitte Omnia platform, a cloud-based, end-to-end global audit solution, is tailored for larger audits, including publicly listed entities. This digital tool enhances their ability to see the bigger picture and extract deeper insights, delivering greater value 

Most of Deloitte’s AI projects are focused on improving processes and gathering useful insights. 

2. EY

EY has put AI to work in a couple of big areas: 

a. Contract Review:

AI is used to pull out key details from lease contracts, like start dates, payment terms, and renewal options. This saves time by handling repetitive tasks automatically. 

b. Audit Help:

EY is testing AI to speed up the audit process. Instead of spending hours going over documents, employees can focus more on analyzing the numbers. EY says these AI tools can review around 70-80% of simpler contracts electronically, leaving humans to handle just the complex parts. 

3. PwC

PwC has put a lot of effort into using a type of AI called Natural Language Processing (NLP): 

a. Natural Language Processing (NLP):

NLP helps PwC go through long, detailed documents, such as lease contracts, revenue agreements, and meeting notes. This tool finds the important details that PwC’s clients need, making it easier for them to make informed choices without reading through stacks of paperwork. 

4. KPMG

KPMG’s AI projects are all about pulling out information, spotting trends, and ensuring compliance: 

a. Call Center Analysis:

Their AI tool turns customer calls into text to analyze common themes and predict customer needs. It looks at keywords, customer sentiment and predict future trends. 

b. AI Anomalous Event Predicting Tool:

KPMG uses AI to forecast events, helping clients prepare for what might happen next by spotting unusual patterns early. 

c. Document Compliance:

KPMG’s compliance tool scans entire documents—such as contracts and lease agreements—to find key details and help make sure clients meet legal requirements. 

The Big 4 are leading the way in showing how AI can make complex work easier and more efficient. Deloitte, EY, PwC, and KPMG are using AI not only to speed things up but also to bring new insights and better service to their clients. This is how they’re setting a new standard for accounting with AI. 

The Bottom Line 

Hiring Deloitte, PwC, EY or KPMG speaks for itself - access to top-of-the-line online bookkeeping services, licensed and well-versed talents onboard, exposure to a larger network and stronger client relations.  

Work with D&V Philippines 

Is working with large accounting firms not an option for you? Work with D&V Philippines instead.   

Our team of seasoned accounting professionals, most of whom have experienced working in the Big 4, brings the skills and experience of top-tier accounting firms to support your business with the same trusted excellence. Schedule a free consultation with us today to learn more about our services.  

You can also download our whitepaper, Finding the Right Talents: D&V Philippines’ Solutions to Modern Accounting Firms to learn more about what sets us apart from other outsourcing firms. 

This post was first published on 14 February 2017 and edited on 02 January 2025. Edited by: Angelica Garcia