Underperformance at MBB is often less dramatic than people imagine. It is usually not one catastrophic mistake. More often, it is a pattern where someone is not progressing at the expected rate across problem solving, communication, ownership, or team effectiveness.
A consultant can be hardworking and still receive weak feedback if the work consistently requires too much correction, if they struggle to synthesize, or if managers cannot trust them to own increasingly complex pieces of the project. Expectations also rise quickly, so performance that was acceptable six months ago may no longer be enough.
Early signs can include repeated feedback on the same issue, managers narrowing your scope instead of expanding it, difficulty getting staffed onto preferred projects, or reviews that emphasize the need for rapid improvement. None of those automatically means someone is being pushed out, but repeated patterns matter.
The healthiest way to think about the system is as a progression model rather than a constant firing threat. Strong firms should give feedback and opportunities to improve. If you are receiving consistent feedback, acting on it, and showing upward movement, one rough project or difficult manager does not define your trajectory. A useful reference is performance expectations for new consultants.