When you are working on a case related to client analysis, how do you know if the client portfolio is too concentrated? Are there any metrics to determine this? For example, if the top 10 customers collectively account for more than 50% of turnover... or if there is a customer that accounts for more than 20% of turnover .... etc. How do you analyse this?
What worries me most is how to justify the answer to an interviewer. What to base the reasoning on to say that one criterion or the other is the most appropriate.