CaseClimbThis guide sorts consulting firms into four groups: MBB, Tier 2 strategy firms, the Big 4 consulting arms and boutiques. For each you get the typical project, team and client, how hiring works, what the interviews look like and who does well there. Then come a summary, a way to decide, advice on applying to several groups at once, and how the case differs by group.
Treat the tiers as an informal industry convention that people apply in different ways. No official body publishes the list, and a firm one candidate calls Tier 2 another calls a large boutique. Large firms also contain teams that work like a different group, such as a strategy unit inside a Big 4 firm. Use the groups to organise your research, then judge each firm and office on its own terms.
MBB: McKinsey, BCG and Bain
MBB is shorthand for McKinsey, BCG and Bain, the three firms most candidates name first when they think of strategy consulting. The typical project is a question a chief executive or a board wants answered within a few months: whether to enter a market, how to restructure a cost base, which acquisition to pursue, how to turn around a business unit that is losing money. Many projects also run into implementation.
Teams are small, often a partner, a project leader and two to four consultants, and the client contacts tend to be senior. Hiring runs through structured campus programmes for undergraduates and MBA students, plus experienced-hire routes for people from industry. Screeners see many CVs for each place, so academic record and leadership carry weight at the first cut.
Interviews combine case interviews and fit questions across two or more rounds, and many offices add an online test or a game-style assessment before the first round. Cases tend to be broad business problems with a mix of structure, numbers and judgement. People who thrive in this group enjoy ambiguity, learn fast from direct feedback, and are happy to change industry and topic from one project to the next.
Tier 2 and other strategy firms
Tier 2 is the loose label for strategy firms outside MBB that run a similar model and a similar interview. Common examples include Oliver Wyman, Kearney, Roland Berger and L.E.K. Consulting, along with others that vary by region.
Project types overlap with MBB: growth strategy, due diligence for private equity, operations and cost work, pricing, organisation design. Some firms lean toward particular industries or functions, such as financial services, transport, manufacturing or investor work, and you will see that lean in their published case studies. Teams are small and client contacts are senior, though the client mix can be wider and some projects shorter.
Recruiting looks like the MBB process at a smaller scale: campus events, a CV and cover letter, often an online test, then case and fit rounds. Intakes are smaller, and candidates report that a referral or a good conversation at an event can earn a closer read. The people who thrive here want strategy work with a sharper focus and more responsibility early in a smaller team.
The Big 4 consulting arms
The Big 4 are Deloitte, PwC, EY and KPMG. Each runs a consulting business alongside audit, tax and advisory, and those consulting arms are large, with many service lines under one brand. Projects range from strategy and transaction work to technology implementation, finance transformation, risk, supply chain and human resources.
Team size varies. A strategy project may look like a small strategy-firm team; a technology programme may involve dozens of people from several countries for a year or more. Hiring is high volume and organised by service line, so you apply to a specific team, for example strategy, technology or operations, and the interview reflects that team.
Interviews often mix competency questions, a case or a written exercise, sometimes an assessment centre, and technical questions for technical service lines. People who thrive here want depth in a function or a technology, value a large network of colleagues and formal training, or want to see a change through from design to go-live.
Boutiques
Boutiques are smaller firms that focus on one industry, such as healthcare, energy or consumer goods, or on one function, such as pricing, procurement, digital or due diligence for investors. Projects sit inside that focus, and you build expertise fast because you see the same type of problem many times across different clients.
Teams are small, and a junior can end up close to the partner and the client from the first week. Client contacts are often the head of the function the boutique serves. Recruiting is less formal. Many boutiques hire as roles open, outside the campus calendar, through referrals, job boards and direct applications.
Interviews vary the most in this group. Expect a case drawn from the firm's speciality, questions that test your interest in the industry, and at times a modelling or analysis task. People who thrive at a boutique already know the field that excites them, enjoy being the expert in the room, and prefer a smaller team to a famous brand.
The four groups side by side
- MBB: broad strategy and transformation work for senior executives; case and fit rounds, often after an online test; suits people who want wide exposure across industries.
- Tier 2 strategy firms: strategy, operations and due diligence work, often with an industry lean; case and fit rounds close to MBB; suits people who want strategy work with a sharper focus.
- Big 4 consulting arms: strategy through to large implementation programmes, by service line; competency questions, a case or written exercise, sometimes an assessment centre; suits people who want technical depth and to see changes delivered.
- Boutiques: deep work in one industry or function; cases from the speciality and questions on your interest in it; suits people who know the area they want to master.
Choosing which groups to target
Answer four questions in writing before you build your list. Most candidates find that one answer outweighs the others, and that answer should shape the shortlist.
- The skills you want to build: a broad problem-solving toolkit points to MBB and Tier 2; depth in technology, finance or operations points to the Big 4; mastery of one field points to a boutique.
- The industry you care about: if you already know it is healthcare or energy, look for the firms with a strong practice there, which can put a Tier 2 firm or a boutique ahead of a bigger name.
- Lifestyle: hours and travel depend on the project, the office and the client more than on the group. Ask people in the office about staffing and travel.
- Exit options: strategy firms tend to lead to corporate strategy, private equity and start-up roles; Big 4 work tends to lead to functional leadership, technology and finance roles; boutique experience tends to lead to roles inside the same industry. Many people move between groups during a career.
Applying to several groups at once
Most candidates apply to more than one group in the same season, and screeners expect that. The risk lies in sending the same motivation to all of them. Interviewers ask "why this firm" in most fit rounds, and they notice an answer that would fit any competitor. Tailor it first to the group and then to the firm, using what you learned from its people and its published work. The fit interview guide covers how to build the stories behind those answers.
Take a candidate with an engineering degree who applies to a strategy firm, a Big 4 operations team and a supply chain boutique. A weak answer reads the same for all three: "I am drawn to your firm because of its strong reputation, its people and the variety of projects." Stronger versions name something specific to each group:
- Strategy firm: "I want to learn to frame a problem from the top down across different industries. Two of your consultants described moving from a market entry question to an operations plan within a year, and that range is what I want from my first years."
- Big 4 operations team: "I enjoy the point where a plan meets the factory floor. Your team stays on through implementation, and I want to learn how to make a new process stick, which my engineering placement only let me watch from the outside."
- Supply chain boutique: "Supply chain is the problem I keep coming back to. At a firm that focuses on it, I would see the same question across many clients and build a depth I could not build at a generalist firm."
Keep a short note for each firm with the people you spoke to and the reason it fits your plan, and reread it before each interview. Campus deadlines for strategy firms and the Big 4 often fall in the same weeks, while boutiques hire through the year. Build your case skills first, because they carry across all four groups; a four-week prep plan fits before the first deadline.
Case interview differences across groups
The core of a case interview is the same in all four groups: you clarify the question, build a structure, work through the numbers and give a recommendation. The guide to structuring a case covers that core. The differences sit at the edges.
- MBB and Tier 2: broad business problems, run either interviewer-led with set questions or candidate-led where you drive each next step. Expect clean mental maths.
- Big 4: cases often tie to the service line you applied to, such as a cost reduction for an operations team or a system choice for a technology team. Some rounds use a written case or a presentation you prepare in advance, and competency questions can take up more of the hour.
- Boutiques: cases drawn from the speciality, sometimes with industry data you are expected to read, and follow-ups on how that industry makes money.
Ask the recruiter or a consultant about the format before each round. Formats change over time and differ by country.
Common questions
Is a Tier 2 firm a step down from MBB? For many careers it is a different choice with its own strengths. The labels describe size and brand recognition more than the quality of the work. Pick the firm whose projects and people match what you want to learn.
Can I move from a Big 4 firm to a strategy firm later? Many people do, as experienced hires or after an MBA. You will still sit case interviews, so keep your case skills practised and build a record of work you can describe in business terms.
Should I apply to boutiques if I have not chosen an industry? You can if the speciality interests you, though interviewers will probe that interest, and a vague answer about why their field is hard to recover from.
Do I need different case preparation for each group? Prepare the shared core first: structure, maths and synthesis. Closer to each interview, add cases from the firm's industries or service line and practise the format that firm uses.
Whichever group you choose, the case interview decides most offers. You can practise full cases with feedback on the case training page.
