Not sure why the other comments are so negative. I don't see how you can dispute that having a large part of your net worth in a single stock leaves you vulnerable if anything happens to it. There's also the fact that your fortunes are still very closely tied to your company's through unvested stock, bonuses, and employment. Regardless of how positive you are on your company, you're probably already sufficiently invested in it. I can't imagine any combination of individual situation and risk tolerance that would make holding a large amount of a single publicly-traded stock an optimal investment strategy.