Internship by MBB and big 4

BCG McKinsey and Bain internship MBB
New answer on Mar 16, 2023
5 Answers
Anonymous A asked on Mar 15, 2023

What are some effective ways to prepare for internship applications at MBB firms and big 4 companies, especially for individuals struggling with chart interpretation and math skills?

Should one focus on practicing with other candidates or is it more beneficial to read and deeply analyze business cases?

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Content Creator
replied on Mar 16, 2023
Ex-Bain and interviewer for 7+ years | >95% success rate | mentor and coach for 6+ years

Hi there,

I think this is an interesting question that may be relevant for many people. I would be happy to share my thoughts on it:

  • First of all, it's great to see that you've already developed an understanding of your weak spots. In general, I would highly advise you to do both.
  • Practicing case studies with peers and/or a coach will always provide you with the most realistic experience for the interviews you may encounter.
  • Moreover, working specifically on your weak spots will ensure you progress even more quickly in those areas, ensuring you develop strong case study skills in a shorter period of time.
  • Lastly, while reading and conducting case studies on your own might be helpful in the very beginning of your preparation, the added value of this approach decreases quickly.

If you would like a more detailed discussion on how to address your specific situation, please don't hesitate to contact me directly.



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Content Creator
replied on Mar 16, 2023
#1 Coach for Sessions (4.000+) | 1.500+ 5-Star Reviews | Proven Success (➡ | Ex BCG | 10Y+ Coaching

Hi there,

Q: Should one focus on practicing with other candidates or is it more beneficial to read and deeply analyze business cases?

I would recommend a mix of the two, as you are going to develop different skills by practicing and reading. Both can be useful if you work on the right material.

For math, you can find more info here:

How to Answer Properly Any Math Question

For graphs, you can find more info here:

How to Analyze any Graph

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In terms of general preparation, I would recommend the following:

  1. Define a calendar for your preparation. Identify how many hours you have before your interview and allocate a time slot for preparation in your calendar for each day, working on the points below. Many candidates need 100+ hours to be ready before the interview starting from zero so you can keep that as a benchmark.
  2. Start reading good MBA Consulting Casebooks – you can find several for free online (INSEAD is a good one to start). Read the cases and try to apply your structure to solve them. Whenever you see there is something missing, upgrade your structure with the new insights. Try to read a new case per day – in this way you will absorb better the information with constant learning.
  3. After the first 5-10 cases in books/casebooks and basic theory, start to practice live. PrepLounge can be helpful to connect with other candidates for that. There is a relevant part of the interview score that is based on your communication, which you cannot practice at all if you read cases only.
  4. Keep track of your mistakes and see which ones you are repeating. This is very important, as otherwise you may do a ton of cases without fixing the real issues. If you find common mistakes, try to identify the reason for them (feedback from experienced partners would be particularly useful for this). Be sure to focus on both the behavioral part and the case part during the mocks. The case part should also cover market sizing, math and graph analysis.
  5. Before your application, be sure to review your CV and Cover, so that they are in the required format for a strategy role.
  6. At least 3 weeks before the application deadline, start networking to find referrals. You can find some tips here.
  7. Before the interviews, be sure to prepare your questions for the interviewer – a great way to show you prepared in advance and to connect with the interviewer for a good final impression. Ideally, try to get information on who they are and study their profile to have good questions to ask.

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If you have to do the BCG Online Case Chatbot or McKinsey PSG Solve, you can find some material to prepare below (full disclosure – I am the author;) ).

▶ BCG Online Case Software Simulation

▶ McKinsey Solve Game Video Simulation

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If you want to spend a few hours only instead of 100+ and cover everything mentioned above, I developed a program precisely for that. 

I can also share with you real questions for your target office (I have a db with 1.500+ questions asked in 60+ offices you won't find anywhere else - you can check on my profile if I cover your particular office).

You can check the program at the following link to learn more:

▶ GYM Program

If you have any questions please feel free to PM me.



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Content Creator
replied on Mar 16, 2023
MBB | 100% personal interview success rate (8/8) and 95% candidate success rate | Personalized interview prep

Hi there,


You're looking at this very narrowly and I am quite concerned.

In general:Please don't just read cases. You need to live case. Please don't just case. Like a soccer team, they don't just play games and scrimmage…they do dribbling, passing, shooting drills. You need to do the same.

Please read this article:

For chart/math: I like Rocketblocks for this

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replied on Mar 15, 2023
FREE Intro session | Deloitte Senior Consultant | Big4 & Boutiques coaching | Strategy & Operations | LBS MBA

Hi there, 

There's tons of material and advice on PrepLounge which can help you to develop your study plan - would scroll through the Q&A as well as some guides that experts have developed. 

You should draw on this info to develop your own personal study plan and spend more time on things that you currently struggle with (i.e. charts and maths as you mentioned).

Generally, I recommend 1-2 months to prep for your interviews but that obviously depends on when your interviews are (some of my candidates do a 3-day crash course with me, and while that's not advised, it can work!).  As a high-level overview…

  1. CV, CL, and supporting documents - do detailed company research and get your motivation piece crystal clear.  Working on your behavioural responses in parallel can also be quite useful while youre at it.
  2. Introduction to theory & frameworks - Materials such as Case in Point by Victor Cheng, Porters 5 forces framework, P&L framework, operating model frameworks etc. will help to give you the basics on how the case interviews work, what the key frameworks are, example cases and how to structure your approach.  What can also be helpful is to look at videos (youtube or on PrepLounge) to see sample interviews from other candidates and get a hang on the structure of the case interviews and what good, bad and ugly problem solving looks like!
  3. Put theory into practice!  Practice cases firstly with peers (via PrepLounge or with friends) and then, if possible, with actual consultants working for your target firms.  The more cases you do, the more comfortable you will feel in the interview chair.  Also, make sure you really take the time to reflect on your interviews, go back through the questions, see what you could have done better etc.

PrepLounge experts such as myself can help guide you, structure your preparation, provide you with lots of materials (theory & cases) not available online and give you valuable and actionable feedback on what you need to improve and how!  Feel free to reach out for more information!

Best of luck!


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CoachingPlus Expert
replied on Mar 15, 2023
PL-level BCG experience (6 years)|Interviewer at BCG| 6/6 personal + 95%+ candidates offer success rate

Hi There,

you should aim for an holistic preparation and study plan based on the timeline you have in mind between now and hypothetic 1st round interview.

Many coaches on the platform (including me) can offer this to you.

Happy to deep dive on specific topics, but the conceputal building blocks to me are

1) “Top of funnel optimization”: maximize number of interviews vs. applications

Strategy varies drastically between e.g. MBA students in Target MBA program for MBB / undergrad but in general I would say

→ Informed selection of target firms / geos /offices 

→ Perfect CV and Cover Letter checking w/ experts for every firm

→ Use network (school or build one through e.g. linkedin) to have “referrals” or “warm introductions” to target firms/geos/offices

2a) Build the Case Hard Skills

You can find detailed info in most coaches profiles about programs to do this ( which include chart interpretations and math skills).

In general my advice would be to split

→ In early phase (2-3 weeks) 70% self-study on the basics hopefully guided by a coach

→ Then 60-70% practice w/ peers and 30% “self-study” on any topic (including math)

On math and chart interpretation specifically, you can find specific resoruces here on the platform for self-study which are very good both for Math and chart interpretation. Feel free to DM me for more details

 2b) Prepare FIT interview

My advice is to start deep-diving at midpoint btw. start of preparation and interview. Most applicants overlook this but this has a considerable weight in decision to progress beyond 1st stage, especially when applicant pool is competitive (read good CV and good at casing) 

→ Self-reflection, Story-Matrix, and deep-dive on WHY consulting, WHY firm and your USP are the must 

3) Prepare for “first 3 months” success on the job

Even here I would urge to talk with ex-senior MBB people in this platform to get a bit guided here. Can make a difference on how hard the ramp-up is for you, in the happy event of you accepting a job offer.


Hope this helps

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Hagen gave the best answer


Content Creator
Ex-Bain and interviewer for 7+ years | >95% success rate | mentor and coach for 6+ years
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