It is time to sell a stock when the points in your buy case have turned negative, but beware of false signals that can trick you into selling at the wrong time. 
Your buy case was built to support buying the stock 
This written case is your reason for owning the stock. The only reason for selling the stock is if something changes the buy case. Here are some events that can fool you into selling, but may not mean your buy case has been compromised: 
- Falling stock price – A      drop in stock price is not necessarily a reason to sell (it may, in fact      be a signal to buy). Remember that you are investing in a company and its      stock may not always reflect its true value. Re-check the company’s      fundamentals and if they haven’t changed, the stock is probably reacting      to market conditions that are affecting all stocks or all stocks in the      same sector. If the company remains a strong buy, it may be time to add      more to your portfolio. 
 - Stock price rises – Oddly      enough, investors sometimes can’t stand a good thing and sell after the      stock has gone up. Stocks prices don’t necessarily operate by the laws of      gravity. Just because they have gone up doesn’t mean they are doomed to      come down. Some stocks keep going up for long periods, which is the idea. 
 - Bad news and rumors – Bad      news about a stock/company can send a stock down. It might be a story      about the company missing earnings or something more serious like a      government investigation. Before an emotional “Oh my gosh” reaction, get      facts, not rumors to assess the full impact of the news. Is this a bump in      the road or a major wreck? Unless it is a serious problem, most bad news      goes away quickly unless it involves criminal proceedings or a fundamental      change in the company’s core business (government action eliminates a key      product). Hang over bumps. If it’s truly a wreck, it is probably time to      cut your losses as quickly as possible. 
 
Knowing when not to sell is as important as knowing when to sell.
(By Ken Little)
















