Companies like to make a big deal about identifying and developing "high potential" employees. These are the people that the company things have the potential to grow into bigger and bigger roles. Companies tend to spend more time and effort developing this high-potential employees, sometimes at the expense of everyone else.
I'll save the topics of how bad companies are at identifying these individuals and how bad they are at actually developing them for another time.
My focus is on the absolutely insane policy some companies have of not telling high-potentials that they are high-potentials. I've heard several reasons why they do this, none of them good. In fact, most of them are mind-numbingly bad. I actually had one manager once tell me that he didn't want to tell someone they were a high-potential because then they would start to think that they were a better performer than everyone else, and that would be bad for team morale.
Wut? Isn't the reason you selected them as a high-potential the fact that they are a better performer?
Everyone should have a development plan. Be honest with the high-performer. Let them know that they are viewed as someone who has potential. You can't promise them a promotion or raise, but you and the company have high expectations.
Once the employee knows this, they will be encouraged to work harder. If they start to coast because they think they've "made it", then you know they weren't the high performer you thought they were.