Deloitte
The largest of the four by revenue.
- Revenue, FY2026
- US$74.5 billion
- People
- Nearly 500,000
- Consulting
- Strategy, Risk & Transactions and Technology & Transformation
- Strategy arm
- Monitor Deloitte
Big 4 consulting firms: who they are and how they hire
The Big 4 are Deloitte, PwC, EY and KPMG, four global networks that audit companies and also run large consulting businesses. Each has a strategy arm that competes for the same strategy work as McKinsey, BCG and Bain: Monitor Deloitte, Strategy& at PwC, EY-Parthenon and KPMG's Global Strategy Group. Deloitte is the largest, with US$74.5 billion in revenue for its 2026 fiscal year. Deloitte, PwC and EY-Parthenon all describe case interviews for consulting roles. Every consulting route into the Big 4 runs through a case or a scenario. Soreno, an AI voice interview practice app for consulting, investment banking and other finance candidates, runs Big 4 style cases and fit questions with follow-ups and scored feedback.
Updated
- Four firms. Deloitte, PwC, EY and KPMG. Each audits, advises on tax and runs a consulting business.
- Four strategy arms. Monitor Deloitte, Strategy& (PwC), EY-Parthenon and KPMG's Global Strategy Group do the work closest to MBB.
- Big by revenue. Deloitte US$74.5B, PwC US$60.2B and EY US$57B in fiscal 2026, KPMG US$39.8B in fiscal 2025, each from its own results.
- Strategy through delivery. The firms pitch strategy that they then help carry out, across technology, deals and operations.
- A case in most interviews. Deloitte, PwC Advisory, Strategy& and EY-Parthenon all name case interviews on their careers pages.
The Big 4 and their consulting and strategy arms
Each firm is a network of member firms that share a brand. Below, each consulting and strategy arm is described in the firm's own words, and size comes from each firm's latest global results, read on October 28, 2026.
PwC
Advisory is its largest line of service.
- Revenue, FY26
- US$60.2 billion
- People
- More than 360,000
- Advisory, FY26
- US$25.8 billion
- Strategy arm
- Strategy&
EY
Reports Consulting and EY-Parthenon separately.
- Revenue, FY26
- US$57 billion
- People
- 415,182
- Consulting, FY26
- US$17.4 billion
- EY-Parthenon, FY26
- US$6.8 billion
KPMG
Its fiscal year ends September 30.
- Revenue, FY25
- US$39.8 billion
- People
- 276,030
- Consulting
- KPMG Advisory
- Strategy arm
- Global Strategy Group
What each consulting and strategy arm does8 arms
Each firm has a broad consulting business and a smaller strategy arm. Their own descriptions:
Monitor Deloitte
Deloitte's strategy practice
Deloitte US says "At Monitor Deloitte, we help clients craft bold, transformational strategies that drive profitable growth": enterprise and business unit strategy, growth strategy and business model innovation.
Deloitte case interviewDeloitte consulting
Strategy, Risk & Transactions plus Technology & Transformation
Deloitte names these two businesses as its consulting services. It calls SR&T its strategic advisory business, working with executive teams, boards and investors, and T&T its technology driven transformation work.
Strategy&
PwC's strategy consulting business
Strategy& calls itself "the only at-scale strategy business that's part of a global professional services network". It took its current form in 2014, when Booz & Company joined the PwC network, and cites 3,000+ strategy consultants.
Strategy& case interviewPwC consulting
Strategy carried into delivery
PwC US says it designs forward-looking strategies and drives seamless execution, across operations, the front office, cyber, deals, technology and finance.
EY-Parthenon
EY's strategy and transactions arm
EY calls EY-Parthenon a global strategy consulting firm that works with CEOs, boards, private equity investors and governments on growth, strategic transformation and value creation. Its FY26 revenue grew 7.4% in local currency, the fastest of EY's four service lines.
EY-Parthenon case interviewEY Consulting
Business transformation
EY describes Consulting as business transformation through people, technology and innovation. At US$17.4 billion in FY26, it is EY's second largest service line after Assurance.
KPMG Global Strategy Group
KPMG's strategy practice
KPMG says its Global Strategy Group works with private, public and not-for-profit organizations, and that its strategy services focus on agile strategies.
KPMG Advisory
Performance, risk and technology
KPMG US says clients come to KPMG Advisory to improve business performance, turn risk into opportunities and embed technology across the organization.
KPMG interview questions
Size, from each firm's own results4 firms
Fiscal years end on different dates, so compare with care. Shares are our math from each firm's published numbers.
Deloitte
US$74.5B, year to May 31, 2026
Up 3.8% in local currency. Deloitte says it has nearly 500,000 people in more than 150 countries and territories. It does not split out a single consulting revenue figure in the release, and gives growth for SR&T (4.4%) and T&T (2.5%).
PwC
US$60.2B, year to June 30, 2026
Advisory brought in US$25,832 million. That is 43% of PwC's revenue (25,832 / 60,226, our math). PwC cites more than 360,000 people in 130+ countries and territories.
EY
US$57B, year to June 2026
Consulting US$17.4B and EY-Parthenon US$6.8B, together 42% of revenue ((17.4 + 6.8) / 57, our math). EY counts 415,182 people at the end of June 2026.
KPMG
US$39.8B, year to September 30, 2025
Its latest global results as of October 2026, on a continued operations basis. Advisory grew 2.9%. Headcount was 276,030. In the US, KPMG cites 80+ offices and 36,000+ employees and partners.
From Deloitte: FY2026 revenue, Deloitte: Monitor Deloitte US, Deloitte: Monitor Deloitte, PwC: FY26 results, PwC: consulting, Strategy&: who we are, Strategy&: history, Strategy&: about us, EY: FY26 revenue, EY-Parthenon: strategy, EY: consulting, KPMG: FY25 revenue, KPMG: strategy services and KPMG US: early career.
How the Big 4 differ from MBB
MBB means McKinsey, BCG and Bain, firms that only do consulting. The differences below are our reading, with the firm's own words where a point rests on a fact.
Audit firms that also consult
The Big 4 audit public companies, and audit rules limit what they can sell an audit client. Deloitte US notes that "certain services may not be available to attest clients under the rules and regulations of public accounting." MBB have no audit business.
Strategy is one arm, not the whole firm
At MBB, strategy work is the core. At the Big 4 it sits in a strategy arm inside a far larger consulting business, so where you join decides what work you do.
Strategy carried into delivery
Each firm pitches strategy it then helps carry out. Deloitte says it aligns "strategy with execution", Strategy& says it works "from strategy through to execution" and EY-Parthenon designs solutions "that work in practice, not just on paper".
Many entry points
The Big 4 hire into strategy, technology, deals, risk and public sector teams, each with its own postings. Our reading: you pick a team when you apply, while at MBB you join a generalist pool.
Similar interviews
Both test structured thinking in a case. The Big 4 cases often draw on the work that team does, such as a digital transformation at a bank in PwC's own sample case.
From Deloitte: Monitor Deloitte US, Deloitte: Monitor Deloitte, Strategy&: US home, EY-Parthenon: strategy and PwC: case interview prep.
How each Big 4 firm hires, from its careers pages
Each firm hires undergraduates and MBAs into its consulting and strategy teams. Here is what each one's US careers pages say about roles and interviews, read on October 28, 2026.
DeloitteCase and scenario interviews
Deloitte says candidates "may go through a mix of behavioral, technical, and case-based interviews, depending on the role." Its Case Prep Tool has separate practice cases for undergraduate and advanced degree students, and its tips ask for a five step approach: understand the issue, name assumptions, summarize findings, recommend, then give next steps.
Deloitte: student careersOur Deloitte interview guide
PwC and Strategy&Assessment, then live virtual interviews
PwC sends most entry level applicants an assessment within a few hours of applying. Candidates typically do two live virtual interviews in a row, and "the majority of our Advisory positions require a case interview." Strategy& MBA candidates do one round of three virtual interviews, each with a case and a behavioral part, and PwC aims to give an offer decision within three weeks.
PwC: entry level recruitingOur PwC interview guide
EY and EY-ParthenonBehavioral and case interviews
EY-Parthenon runs an Associate Program for undergraduates and master's students and a Consultant Program for MBAs. Candidates "can expect a mix of behavioral and case-based interviews with multiple EY-Parthenon professionals," and offers typically come within a week. EY says its wider process can include online, written or face-to-face assessments.
EY-Parthenon: careersOur EY-Parthenon case guide
KPMGTwo live video interviews
KPMG US recruits on a rolling basis and lets you hold at most two active applications. Interview picks come typically within two weeks of applying, then two live video interviews with business leaders, and most decisions within two weeks after that. Its US early career page does not describe a case interview, as of October 2026.
KPMG US: early careerOur KPMG interview guide
Which Big 4 firm fits whom, in our words
This is Soreno's own guidance, not firm data. Pick by the team and the work, then by firm.
Six kinds of candidate
Pure strategy
Aim for the strategy arm
If you want the work closest to MBB, apply to Monitor Deloitte, Strategy& or EY-Parthenon. Their interviews lean hardest on cases.
Technology
Tech strategy and transformation
If you like systems, data and AI, the technology teams fit, such as Deloitte's Enterprise Tech Strategy or EY Consulting. Expect case questions about technology choices and roadmaps.
Deals
Transactions and private equity work
If you are drawn to M&A and investors, EY-Parthenon and the deals teams at each firm fit. Our reading: it builds the deal skills private equity firms look for.
Consulting to private equityFrom EY-Parthenon: careers.
Public sector
Government and public services
If you want public impact, look at each firm's government and public services teams, which hire their own consultants.
Accounting majors
Start close to your degree
Risk, forensic and valuation teams draw on accounting. Deloitte's Case Prep Tool includes forensic and valuation practice cases.
From Deloitte: Case Prep Tool.
MBB hopefuls
Apply to both
The interviews overlap, so prepare once and apply to MBB and Big 4 strategy arms in the same season.
MBB consulting
Our guidance. For firm facts, see the firm list above.
16 Big 4 consulting interview questions to practice
Big 4 interviews mix fit questions with a case drawn from the team's work. Our own wording, with what a strong answer does.
Why the Big 45 questions
The questions that test your reasons.
Why consulting?
What a strong answer does
Two reasons backed by things you have done, tied to the kind of work this team does. Practice it, see a model answer
Why this firm?
What a strong answer does
Something specific you learned from the firm's people or pages, such as how its strategy arm works with the rest of the firm. Practice it, see a model answer
Why the Big 4 and not McKinsey, BCG or Bain?
What a strong answer does
A positive reason about the work, such as seeing strategy carried into delivery, never a line about MBB being out of reach.
- “Have you applied to MBB as well?”
- “What would make you pick us over an MBB offer?”
Why this team and not another part of the firm?
What a strong answer does
Shows you know what this team does day to day, and connects it to a skill or interest you can prove.
- “Which other teams did you look at?”
Walk me through your background.
What a strong answer does
Two minutes, in order, each step leading to the next, ending on why this role now. Practice it, see a model answer
Behavioral5 questions
Stories about how you work with people.
Tell me about a time you dealt with ambiguity.
What a strong answer does
A real situation with unclear facts, the structure you put on it and what you decided. Practice it, see a model answer
Tell me about a conflict with a teammate.
What a strong answer does
Your part in it, how you raised it directly and what changed in the work. Practice it, see a model answer
Tell me about tough feedback you received.
What a strong answer does
Specific feedback, what you changed and proof the change stuck. Practice it, see a model answer
Tell me about an ethical dilemma.
What a strong answer does
A real gray area, the line you held and how you raised it. Integrity matters doubly at firms that audit. Practice it, see a model answer
What are your strengths?
What a strong answer does
Two strengths the job uses, each with a short example and its result. Practice it, see a model answer
Case prompts6 questions
Cases shaped like the work Big 4 teams do.
A large bank wants to move its customers to digital banking within two years. What risks should it plan for?
What a strong answer does
Groups the risks (customers, technology, people, regulation), ranks them and ends with a short road map.
- “Which risk would you tackle first?”
- “How would you measure progress?”
A retailer wants to cut costs by 10%. Where would you look?
What a strong answer does
Splits costs into buckets, sizes each one, then names the cuts that hurt customers least. Practice it, see a model answer
An e-bike maker wants to enter the US. Should it?
What a strong answer does
Market size, competition, the company's ability to win and the economics, ending in a clear yes or no. Practice it, see a model answer
A food company wants to buy a snack startup. Should it?
What a strong answer does
Strategic fit, the standalone value, synergies and the price, then a recommendation with the key risk. Practice it, see a model answer
A manufacturer wants a technology roadmap for AI. Where do you start?
What a strong answer does
Starts from the business goals, then the use cases that serve them, the data and systems needed, and the order to build in.
- “How would you pick the first use case?”
- “What would make the roadmap fail?”
Should a company make or buy a key component?
What a strong answer does
Compares full cost, quality, control and risk on both sides, then picks one with the deciding factor named. Practice it, see a model answer
Myths and how to prepare
Myths about Big 4 consulting
"The Big 4 are only accountants"
Consulting is a large share of each firm. Advisory was 43% of PwC's FY26 revenue, and EY's Consulting and EY-Parthenon together were 42% of EY's (our math from their own results).
"Big 4 consulting has no case interview"
Deloitte, PwC Advisory, Strategy& and EY-Parthenon all describe case interviews on their careers pages, and Deloitte and PwC publish practice cases.
"Every Big 4 job is the same"
Each firm hires into many teams with their own postings. A strategy role and a tax technology role at the same firm have different interviews.
"You can use AI in the interview"
PwC says the use of AI during its assessment and interview process is not permitted.
How to prepare for Big 4 consulting interviews
One plan covers all four firms, then a little firm-specific work.
Step 1
Pick your teams
Read the postings for the teams you want and note what each one does. That shapes your why this firm answer and the cases you will get.
From Deloitte: student careers and PwC: entry level recruiting.
Step 2
Try the firms' own practice cases
Deloitte's Case Prep Tool and PwC's Advisory case page each walk through sample cases. Do them before you practice with anyone else.
Step 3
Practice cases out loud
Do cases out loud, with someone or something asking follow-ups, and say your structure before you dive in.
Step 4
Check the timeline
Big 4 postings often recruit on a rolling basis and close as offers go out. Apply early.
Consulting recruiting timeline
From KPMG US: early career.
Every Big 4 offer starts with an interview
Soreno's AI interviewer runs consulting cases one question at a time, asks follow-ups on your fit stories, then scores the session. Start your free week. Soreno is not affiliated with Deloitte, PwC, EY or KPMG.
Questions people ask
Who are the Big 4 consulting firms?
Deloitte, PwC, EY and KPMG. They are the four large audit and professional services networks, and each runs a consulting business and a strategy arm: Monitor Deloitte, Strategy& (PwC), EY-Parthenon and KPMG's Global Strategy Group.
Which Big 4 firm is the biggest?
Deloitte, with US$74.5 billion in revenue for the year to May 31, 2026 and nearly 500,000 people. PwC reported US$60.2 billion and EY US$57 billion for fiscal 2026. KPMG's latest global figure is US$39.8 billion for fiscal 2025.
Is Big 4 consulting the same as MBB?
No. McKinsey, BCG and Bain only consult, with strategy at the core. The Big 4 also audit, and their strategy arms sit inside far larger consulting businesses that carry strategy into technology, deals and operations work.
What is the Big 4 strategy arm at each firm?
Monitor Deloitte at Deloitte, Strategy& at PwC (formerly Booz & Company, which joined PwC in 2014), EY-Parthenon at EY and the Global Strategy Group at KPMG.
Do Big 4 consulting interviews include a case?
Mostly yes. Deloitte, PwC Advisory, Strategy& and EY-Parthenon all describe case interviews. KPMG US describes two live video interviews and, as of October 2026, does not describe a case on its early career page.
How much do Big 4 consultants make?
Our Big 4 salary page gives median base pay by level from US H-1B filings, with dated reports for the consulting and strategy arms. We keep pay there rather than repeat it here.
Is it easier to get into the Big 4 than MBB?
None of the firms publishes acceptance rates. The Big 4 hire into many more teams, so there are more entry points, and strategy arm rounds center on cases, as at MBB.
Can you move from the Big 4 to MBB?
Yes. The interviews test the same skills, so Big 4 case practice carries over, and MBB hire at the MBA level as well as from undergrad. No firm publishes how many make the move.