My favorite McKinsey failure is the one where UBS (the Swiss Investment Bank) brought them in circa 2000 to understand how they could better expand in the USA.

My favorite McKinsey failure is the one where UBS (the Swiss Investment Bank) brought them in circa 2000 to understand how they could better expand in the USA. McKinsey said something along the lines of "Well - you guys have very little subprime mortgages exposure and we think this is the next hot thing - you guys need to move all your chips into subprime". Fast forward 7 to 8 years and the US was hit with one of the biggest financial crises ever. Caused by what? Sub-prime debt. UBS had some of the biggest debt writeoffs - maybe 2nd to Citi. Source: There is a post-mortem report that UBS released after the financial crises that explains how they got there.