MBB stands for McKinsey, BCG and Bain, the three strategy consulting firms people in the industry also call the Big Three. It is informal shorthand, not a ranking any firm or official body publishes. All three hire through case interviews, and each adds its own online test and fit interview. To rehearse those interviews out loud, Soreno, an AI voice interview practice app for consulting, investment banking and other finance candidates, runs MBB-style cases and fit questions with follow-ups and scored feedback.
Updated
Recruiters, students and consultants use MBB to mean the three firms together, as in MBB recruiting or an MBB offer. Other groups have their own nicknames. None of them is an official ranking, and lists disagree on where some firms sit.
MBB
The three strategy firms. The Big Three means the same thing.
Tier 2
Firms such as Oliver Wyman, Kearney, L.E.K. and Roland Berger. Lists differ on which others belong.
Consulting firm tiers, explainedBig 4
Their consulting arms, including strategy units such as Strategy& at PwC and EY-Parthenon at EY.
Big 4 consulting salaryBoutiques
Firms that focus on one industry, such as life sciences, or one kind of work, such as pricing or economics.
The interview
Each firm hires consultants through case interviews, with a fit or experience interview beside them and often an online test first.
How the interviews differThe hire
Each hires students straight from undergrad and from MBA programs, through internships and full-time roles.
Consulting recruiting timelineThe pay
Median base for an MBA hire is $192,000 at McKinsey, $190,000 at BCG and $192,000 at Bain in US H-1B filings from January 2025 to June 2026.
Consultant salary by firmFrom McKinsey: history of our firm, McKinsey: Global Connect, BCG: our history, BCG: about and Bain: about.
All three use case interviews. What comes before and beside the case differs, from each firm's own careers pages.
McKinsey uses Solve, a game-based assessment, for most consulting roles. BCG in the US starts with an online assessment, and many candidates take an online case of 8 to 10 questions in about 35 minutes. Bain sends some applicants a digital assessment of about 30 to 40 minutes, on Sova or TestGorilla.
McKinsey runs personal experience interviews, where you talk through your own experiences in detail. BCG opens with a skills interview on your experience and motivation. Bain wants to hear why you want to join Bain in particular.
McKinsey calls its case a problem-solving interview. BCG adds a team interview for client-facing roles. Bain gives every candidate for a role the same questions and says its cases have no single right answer.
McKinsey bars outside calculators in its assessments and interviews, so do your math on paper. BCG's online case guide lists one as required. Bain allows one only in its digital assessment.
From McKinsey: interviewing, McKinsey: assessment integrity, BCG: interview process, BCG: online case guide (PDF), Bain: interviewing and Bain: digital assessment.
From each firm's own about and history pages, read on October 26, 2026. Each card links our full guide to that firm's interviews.
McKinsey & CompanyJames O. McKinsey, a University of Chicago professor and expert on management accounting, set up the firm in 1926, its history page says. Its careers site says it has offices in over 130 cities in more than 65 countries.
Boston Consulting GroupBCG's history page names Bruce Henderson as its founder and CEO from 1963 to 1980. Its about page lists offices in more than 100 cities in over 50 countries and 33.5k employees around the world.
Bain & CompanyBain's about page says it has partnered with clients since 1973 and works as one global team across 67 cities in 40 countries.
Our own wording, in the styles all three firms use, with what a strong answer does.
McKinsey's PEI, BCG's skills interview and Bain's fit questions.
Why consulting?
Two reasons backed by things you have done, and what you want to learn in your first years. Practice it, see a model answer
Why this firm, and not the other two?
Something you learned from the firm's people or its own pages, tied to the work you want to do. Never knock the others. Practice it, see a model answer
Tell me about a time you led a group to a result.
Your own moves, how people came along and the result in numbers if you have them. Practice it, see a model answer
Tell me about a time you worked with someone who saw things differently.
Their view put fairly, what you did to understand it and how you decided together. Practice it, see a model answer
The shapes that come up across MBB sample cases.
A regional grocery chain's profits fell 20% in two years. Why?
Split profit into revenue and cost, go one level deeper on each, then say which branch you'd test first and why. Practice it, see a model answer
Should a European e-bike maker enter the US?
Market size and growth, rivals, the client's edge and the cost of getting in. End with yes or no. Practice it, see a model answer
How many cups a day does a new coffee shop need to sell to break even?
Fixed costs over the margin per cup, worked by hand and out loud. Practice it, see a model answer
A streaming service's churn has doubled. What could explain it?
Causes on the customer, product and market side, grouped, then how you would test each. Practice it, see a model answer
The CEO walks in. What do you recommend?
The answer in one sentence, two or three reasons with numbers, the main risk and a next step. Practice it, see a model answer
The case is similar, but the tests and fit rounds are not. A PEI story needs far more depth than a quick behavioral answer.
McKinsey does not allow one in any interview. Do every practice case by hand.
An answer that would fit any of the three tells the interviewer little. Name something you can only say about the firm in front of you.
A case you have only read about rarely holds up under follow-up questions. Say it out loud with someone, or something, asking back.
Many candidates apply to all three, so build one base and add each firm's own parts.
Step 1
Read what each firm says about its rounds. They differ more before and around the case than in it.
McKinsey interview, step by stepBCG case interviewBain case interview examples
Step 2
Solve, BCG's online case and Bain's assessment each have their own format. Know which one you will get before the invitation arrives.
Step 3
Practice both styles: one where the interviewer steers you question by question, and one where you lead. Do the math by hand.
Free McKinsey-style caseFree BCG-style caseFree Bain-style case
Step 4
McKinsey suggests two examples for each of its four PEI areas, and the same stories serve at BCG and Bain. Candidates report the PEI stays on one story for most of its time, so pick ones where you made the key calls.
Step 5
MBB internship deadlines for undergrads can come in sophomore spring. Check each firm's page from January.
Soreno's AI interviewer runs MBB-style cases one question at a time, probes your stories with follow-ups, then scores the session. Start your free week. Soreno is not affiliated with McKinsey, BCG or Bain.
McKinsey, BCG and Bain: McKinsey & Company, Boston Consulting Group and Bain & Company. It is industry shorthand, and none of the firms uses it about itself.
Yes. Both names mean McKinsey, BCG and Bain. The Big Four is a different group: Deloitte, PwC, EY and KPMG.
There is no official answer, and the right one for you depends on the office, the people and the work you want. One published list ranks firms as places to work: the 2026 Vault Consulting 50 for North America, published February 11, 2026, put Bain first and BCG second.
Median base for an undergraduate hire is $112,000 at McKinsey, $110,000 at BCG and $112,000 at Bain, and for an MBA hire $192,000, $190,000 and $192,000, in US H-1B filings from January 2025 to June 2026. Bonuses come on top. Our McKinsey, BCG and Bain salary pages have every level.
No. Deloitte, PwC, EY and KPMG are the Big 4. Their strategy arms, such as Strategy& and EY-Parthenon, hire through case interviews too.
None of the three publishes an acceptance rate or the number of applicants. Treat any figure you see as an outside estimate.
Yes. Each firm runs its own application with its own deadlines, so you apply to each one separately.
