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When to sell a stock?
I am a believer in stocks for the long term, I sat on the S&P right though the last crash, and am 15% below the high before the crash.  For individual stocks, you need to look more closely, and often ask yourself about its valuation. The trick is to buy right and not be afraid to sell when the stock appears to be too high for the underlying fundamentals. Before the dotcom bubble I bought Motorola at $40. Sold some at $80, $100, and out at $120. Coworkers who bought in were laughing as it went to $160. But soon after, the high tech bubble burst, and my sales at $100 looked good in hindsight. The stock you are looking at - would you buy more at today's price? If not, it may be time to sell at least some of that position.