There are two major reasons to exit a position

Kimball Brooker of First Eagle Investment Management in New York says “There are two main reasons to sell. First, if your investment thesis is inaccurate or you own something that wasn't what you thought it was. Second, the sell decision can be linked to intrinsic value. Once a stock price converges with what we believe to be the value of the business, we'll discuss it in the context of trimming. In many cases, intrinsic value is not a static number. It can grow. When we feel a stock is at or above intrinsic value, we’ll trim the position. If the stock price rises far north of intrinsic value, we may have to exit the entire position.” (Source: Graham and Doddsville Newsletter 2015). Read the whole Graham and Doddesville report here: (VIEW LINK)