What are the Big Four? And what's the difference between Deloitte, EY, PWC, and KPMG?

So, you want to work at a Big Four firm. It's tough to get in (although still easier than banking), but if you've got the right stuff, you might find a rewarding career waiting for you. However, there are four firms. So, which one do you pick? Deloitte, Ernst & Young (EY), PriceWaterhouseCoopers (PwC), and KPMG (yeah, just KPMG) are the Big Four. They differ in some extremely critical ways – for example, KPMG has a blue logo, EY has a yellow logo, PwC has an orange logo, and Deloitte has a green dot. What are the Big Four firms? As one might expect, there are four Big Four firms. Deloitte Measured in terms of revenues, Deloitte is the biggest Big Four firm. In 2024 its global revenues totaled $67.2bn, an increase of 3.5% on the year before, and it employed 460,000 people. Deloitte is massive. Like most Big Four firms, Deloitte splits its business into different areas. Those are audit and assurance, consulting, tax and legal, financial advisory, and risk advisory. Deloitte is particularly well known for its consulting arm, which is itself divided into a technology consulting arm, a strategy and operations arm, and a 'human capital' (ie. Managing people) arm. Deloitte's focus on consulting can be traced to the fact that it was the only Big Four firm to retain its consulting arm after the Enron scandal in the early 2000s. PwC PwC is the second biggest of the Big Four. In 2024, its global revenues were $55.4bn, an 11.5% increase on 2023, and it employed 370,000 people. While Deloitte is known for its strong consulting arm, PwC's prominence has traditionally been in audit. It had the highest audit revenue among the Big Four, and that's probably why it's usually seen as one of the most prestigious (if not the most prestigious) Big Four firm to work for. It's also working hard to increase social mobility by, for example, changing the way it interviews students in the UK – interviews are now based around 'future focused' scenario questions which assess candidates' potential, instead of experience-based questions, which focus on past work experience. EY The second biggest in terms of headcount but the third biggest in terms of revenue ($51bn), EY was the smallest big four firm for a long time. EY's business is split into four main groups: assurance, tax, advisory and transaction advisory. Transaction advisory professionals help with things like M&A and strategy advice. Mere advisory professionals include things like risk advisors, IT advisors and people who help make "performance improvements." EY is pushing strongly into technological consulting. It's created an EY Global Innovation Garage (yes) in California to 'foster innovative solutions for EY and its clients.' It employs 20,000 data and analytics practitioners (of whom over 2,000 are actual data scientists) globally. KPMG KPMG is the smallest of the big four firms both by headcount and revenue ($38bn), although its core audit & assurance sector is strong – stronger than Deloitte's, in fact. The firm has a reputation for being more European than some other Big Four firms. Staff insiders describe a culture that is quirky, with less pressure to fit into the stereotypical city graduate lifestyle. KPMG is also big on learning and development, with a high spend on coaching and mentoring, both structured and informal. What is it like to work at the Big Four? Fundamentally, however, they're extremely similar. And not necessarily in positive ways. "The working hours can be awful, and the culture can be harsh. "All of the firms are bleeding people because of how awful it is to work at them" one unhappy auditor informs us. She's only worked at one of the Big Four firms, but says she knows people that have worked at several of them who would happily concur. "Everyone who has ever worked at a Big Four firm would say the same thing. There is little difference between them." Other young professionals, with credentials at multiple firms, agree about their broad similarity. "In my experience, there is very little that differs between the two," says one PwC junior who previously spent over a year at Deloitte. "Both have a similar working internal structure, both with emphasis on building up core skills and guiding you through the work. Both also have a similar working style and pace." He says that the only real difference between the two is that PWC is more demanding with its office hours – three days in, two days at home. That's on par with EY's two-three day regime, but less than Deloitte and KPMG, which operate a more ad hoc in-office system. Deloitte's website says people there can work on a hybrid basis and that its golden rule is that "people are trusted to decide how they work." Deloitte may be clamping down, though: it has begun tying bonuses to office presence in the US. "I consider them to be quite similar culturally," says one senior PwC head who spent several years in Deloitte's consulting teams. It makes sense; Deloitte and PwC are much, much bigger (26,000 employees respectively) in the UK than EY or KPMG (17-18,000 employees, respectively).

Deloitte, Ernst & Young (EY), PriceWaterhouseCoopers (PwC), and KPMG are the Big Four accounting and professional services firms. They are the largest professional services networks in the world and are considered the most prestigious firms to work for in the industry.