The Big 4 companies: Who they are and what they do

6 min read

If you haven’t heard of the Big 4, it’s possible you live under a large, soundproof rock. That’s not to make you feel bad—their entire moniker is based around them being massive.

Regardless, we’re going to take a moment out of our busy schedules to examine the Big 4 companies, what they do, who they are and what makes them so famously large.

What are the Big 4 accounting firms?

That’s the 212-billion-dollar question!

The Big 4 are the largest accounting and auditing firms in the world: Deloitte LLP (Deloitte), PricewaterhouseCoopers (PwC), Ernst & Young (EY) and Klynveld Peat Marwick Goerdeler (KPMG). They’re so big that their joint revenue in 2024 was—you guessed it—$212 billion.

Let’s go into more detail.

Deloitte

Deloitte‘s consulting branch was established in 1995, but the firm was founded way back in 1845 by William Welch Deloitte. It operates out of London but has offices across the world, specializing in strategy, operations, human capital and technology consulting. Deloitte is renowned as a top place to start a career and highly sought-after employer, often working with Fortune 500 companies in finance. Its FY 2024 revenue reached $67.2 billion with a workforce of around 460,000 employees.

PricewaterhouseCoopers

PricewaterhouseCoopers has existed in its current iteration since 1998, but was formed through a merger of Coopers & Lybrand and Price Waterhouse, which were both founded in the 1800s. Often abbreviated to PwC, the firm is a leader in the global advisory market operating in more than 155 countries. Its consulting career areas include strategy, management, risk and technology consulting. PwC is a fairly traditional member of the Big 4, with a strong and established audit client base. Like Deloitte, its headquarters are in London, with FY 2024 revenue estimated at $55.4 billion and approximately 370,000 employees worldwide.

Ernst & Young

Similar to PwC, Ernst & Young was founded in 1989 after the merger of Ernst and Whinney and Arthur Young and Co. In fact, tracing back through the origins of the companies, we land on the English firm Harding and Pullein, which was founded in 1849. Also known as EY, the firm is likewise headquartered in London like Deloitte and PwC. It specializes in business transformation driven by people, technology and innovation, with services including cross-advisory teams, IT risk and assurance, performance improvement and risk management. EY’s FY 2024 revenue was around $51.2 billion, with a roster of around 400,000 employees.

KPMG

Another story of mega-mergers, KPMG was founded in 1987 after Peat Marwick International and Klynveld, Peat Marwick, Goerdeler announced they would be joining forces. Of the Big 4, KPMG is the smallest and also the only one operating outside of London—the firm’s headquarters is in Amstelveen, Netherlands. However, KPMG does operate in over 150 different countries, offering tax, audit and advisory services. Their teams also have expertise in digital transformation, business performance and ESG. They specialize in analytical and technical work, with a Europe-focused approach in comparison to the rest of the Big 4. As of FY 2024, they closed the year with $38.4 billion in revenue and around 275,000 employees.

Why are they called the Big 4?

A very interesting question, and a nice prompt for a brief history lesson. Once upon a time—in recent memory—there existed a Big 8. They were the following firms:

But how did the Big 8 become the Big 4? Various reasons. They merged over time, but the most exciting disruption to the status-quo came down to one of the biggest white-collar scandals in history: Enron.

Enron was an energy, commodities and services company from Houston Texas. It was also the perpetrator of huge corporate fraud in the early 2000s. This was achieved by CEOs Kenneth Lay and Jeffrey Skilling intentionally misvalued the company with special purpose entities (SPEs) to disguise losses. And their accounting partner happened to be a member of the original Big 8: Arthur Andersen.

The bubble eventually burst, of course. In 2001, billions in investor and employee savings were wiped out as investigations shed light on the energy company’s malpractice. This led to criminal convictions for key executives and significant reforms in corporate governance and accounting standards. And Arthur Andersen, of course, went bust for its part in the bad dealings.

Now, industry consolidation had already begun transforming the Big 8 into the Big 4 since 1989. Arthur Young joined Ernst & Whinney; Deloitte Haskin & Sells merged with Touche Ross; Price Waterhouse mixed itself up with Coopers & Lybrand. But the Enron fiasco meant the final nail in the coffin of the 8-way dynasty.

What services do the Big 4 offer?

The Big 4 offer a lot to their clients. That includes audit, assurance, consulting, financial advisory, risk management and tax compliance. They can also help with mergers, acquisitions, corporate restructuring, and forensic accounting—in fact, they all have dedicated in-house legal departments. Not to brag, but IE Law School has very strong connections with these firms, too.

During busy season, typically from January to April when tax reports and quarterly earnings are due, employees often work long hours, sometimes doubling their usual workload. This period is characterized by intense auditing or tax compliance activities to meet strict deadlines. The demanding schedule reflects the critical role the Big 4 play in ensuring accurate financial reporting and regulatory compliance for their clients.

The importance of the Big 4 can’t be understated. Beyond services, they have an international operation that facilitates cross-border transactions. They keep multinational corporations ticking and have a huge influence on research and accounting standards.

How can I work for the Big 4?

Since you’re here, you’re probably interested in working for the Big 4. And you can certainly achieve that goal if you put the right work in. However, while it’s not an absolute requisite, you have to understand that positions are highly competitive. The Big 4 often source graduates from top universities.

All the Big 4 offer diverse entry points into the industry, including work experience schemes aimed at supporting underrepresented backgrounds, summer internships tailored to specific areas of interest, and work placements as part of university programs. These opportunities typically last six to eight weeks, providing hands-on experience and a chance to make a strong impression for future employment. Each firm also runs distinctive initiatives, such as PwC’s social mobility programs, Deloitte’s insight events, EY’s Discover EY program, and KPMG’s Women in Technology week, designed to attract and develop talent.

To succeed in securing a role at one of these firms, you should develop key skills like organization, communication, and problem-solving. Each company also looks for specific qualities: PwC values curiosity and relationship-building; Deloitte emphasizes authenticity, creativity, and growth; EY seeks individuals ready to make an immediate impact and demonstrates confidence; and KPMG appreciates diversity and unique personal experiences. Following their careers pages and engaging in campus events like skills drop-ins and mock interviews can help you better understand what each firm values and how to present yourself effectively.

What are alternatives to the Big 4?

Look, we’re big on the Big 4. We love ’em. But before you apply to work at one of these mammoth organizations, you need to ensure the culture fits your values. For example, each firm has a distinctive environment: PwC is highly prestigious with a reputation for stability; Deloitte is ambitious and results-driven, with a focus on consultancy; EY is known for its emphasis on diversity and inclusivity; and KPMG offers a more relaxed atmosphere with strong staff development programs. So it’s a good idea to talk to people who’ve worked at various firms to give you insights.

Let me speak to you personally—I have many friends who’ve worked at the Big 4 firms. Many loved it. Some hated it.

The attraction is obvious. Career development, good money, prestigious names. But working in a giant corporation simply might not be for you. And there’s nothing wrong with that. There are different cultures for different people, and you just might not “get” it even after working at one of them for a few years.

So, if you’re looking for alternatives, take a look at any of these consulting firms and consider what’s best for you:

RSM

RSM has a focus on the middle market, with a knack for growing expertise in auditing and advising in accounting. 

Grant Thornton

Grant Thornton offers a client-focused approach to audit and advisory services. 

BDO

BDO is a great alternative to the Big 4, functioning across different service areas and markets.

Crowe

Crowe combines global reach with local expertise to offer a boutique but international service.

Satori Assured

Satori Assured specializes in a technology-driven audit approach, with expertise in automation and AI.

Protiviti

Protiviti has a leading niche in risk consulting and internal audit, while also being a respectable provider of general consulting.