Many times that I observed when someone who is top performers left the company, it is always something in the company that throw him off. Jay at Dumb Little Man gathers and consolidates some notes from exit interviews and look into the notes that has been considered in the top 20% in the company. He placed them into categories:

Money Unchallenged Too Challenged Dead Company Watch your Levels (and the BS)

For money, it does not mean top players work for money. But unfortunately employee weight what they worth from compensation. If you couldn’t pay the market rate for those top performer, or the salary package couldn’t catch up their performance, prepare for losing that star employee. Why Top Employees Quit – [Dumb Little Man]