Alternative Metrics, page-67

Just keep in mind that everyone has a reason to sell. Sometimes it's for personal reasons if they need the money, sometimes it's for tax reasons, sometimes it's a matter of taking profits or reshuffling their portfolio. If I'm up 100% on a stock there is a good chance I'll sell half and free carry going forward so that the stock doesn't take up more than a certain percentage of my portfolio.

My point is, there are many legitimate reasons to sell and it doesn't necessarily mean that investors think the company has peaked.