Reading about MF Global declaring bankruptcy under former NJ Governor Jon Corzine's leadership made me think about the most common mishap in management: promoting a top performing employee right into failure. It is a common problem, but it is easier to prevent than you think. When you take Corzine as an example, he was a successful bond trader for Goldman Sachs and by many accounts was promoted to CEO because he made a lot of money for the firm in that role. So what is wrong with making that person a manager you ask?
The skills that made them successful are not ones that make a manager successful. For Corzine the job he was so successful at in no way resembled the CEO's job. A bond trader is a very independent role where former coworkers say Corzine made quick decisions based on his gut instincts. The role of the CEO requires the ability to not only set strategy (which hopefully has been vetted by more than just your gut), but the ability to communicate it clearly to the larger team and to get it followed, if not enthusiastically, then at least correctly.
Were they promoted solely out of the fear of losing them? I think fear is a lousy reason for any management decision, but you have to realize that you will lose what they contribute anyway if you take them out of a job where they are successful and put them in one that they don't have the skills for. You are also likely to lose more than just this employee if they fail as a manager. If the issue is solely money, then you need to make sure they are paid well for the role in which they contribute so highly.
They may be master of their universe, but there is no one in their orbit. By this I mean do they have the ability to connect with others and understand the need to build support for their ideas. Corzine's undoing was his tendency to forge ahead with plans without gaining a consensus according to several people who worked with him. That is a classic independent contributor type of move. As a manager, you have to make sure that your employees are with you when you step forward, and Corzine appears to have taken those steps off the cliff alone.