Is it prudent to sell a stock on a 40% rise in 2 months
Depends entirely on the stock and your perception of it. Would you buy it at the current price? If so, keep it. Would you buy something else? If so, sell it and buy that. Sell half. If it's as volatile as you say, sell it all and buy on another dip. No one can really offer targeted advice based on the amount of information you have provided. Did you buy near the bottom? Suppose you did then the price is still 16% below. 50% fall and then 40% increase leaves a 16% gap. So there could still be upside. However, it appears that you are talking about a small-cap that is volatile. I wouldn't hold it. I would take the money and invest elsewhere. If you have a lot of shares and brokerage is less then sell 60% now and the remaining 40% on either 10-15% jump in price or if it falls by 5% from now. Too risky to hold longer-term.
Ignore sunk costs and look to future returns.  Although it feels like a loss to exit an investment from a loss position, from a financial standpoint you should ignore the purchase price.  If your money could be better invested somewhere else, then move it there. You shouldn't look at it as though you'll be more financially secure because you waited longer for the stock to reach the purchase price.  That's psychological, not financial. Some portion of your invested wealth is stuck in this particular stock.  If it would take three months for the stock to get back to purchase price but only two months for an alternate investment to reach that same level, then obviously faster growth is better.  Your goal is greater wealth, not arbitrarily returning certain investments to their purchase price. Investments are just instrumental.  You want more wealth.  If an investment is not performing, then ignore purchase price and sunken costs.  Look at the reasonable expectations about an investment going forward. 1-2 years is very short-term. If you know you will need the money in that timeframe and cannot risk losing money because of a stock market correction, you should stay away from equities (stocks). A short-term bond fund (like VBISX) will pay around 1%, maybe a bit more, and only has a small amount of risk. Money Market funds are practically risk-free (technically speaking they can lose money, but it's extremely rare) but rates of return are dismal. It's hard to get bigger returns without taking on more risk. "In a sense, yes. There's a view in Yahoo Finance that looks like this   For this particular stock, a market order for 3000 shares (not even $4000, this is a reasonably small figure) will move the stock past $1.34, more than a 3% move.  Say, on the Ask side there are 100,000 shares, all with $10 ask. It would take a lot of orders to purchase all these shares, so for a while, the price may stay right at $10, or a bit lower if there are those willing to sell lower.  But, say that side showed $10 1000, $10.25 500, $10.50 1000. Now, the volume is so low that if I decided I wanted shares at any price, my order, a market order will actually drive the market price right up to $10.50 if I buy 2500 shares ""market"".  You see, however, even though I'm a small trader, I drove the price up. But now that the price is $10.50 when I go to sell all 2500 at $10.50, there are no bids to pay that much, so the price the next trade will occur at isn't known yet. There may be bids at $10, with asking (me) at $10.50. No trades will happen until a seller takes the $10 bid or other buyers and sellers come in." 2.5 years is a short period in the stock market. That means there is a significant chance it will be lower in 2.5 years, whereas it is very likely to be higher over a longer time period like 5-10 years. So if you want the funds to grow for sure then consider an online savings account, where you might earn 1-2%.  If you want to do stocks anyway, but don't have any idea what fund to buy, the safest default choice is to buy an index fund that tracks the S&P 500. Vanguard's VFINX is one example. Yes, you can do this buy placing a conditional order to buy at market if the price moves to 106 or above. Once the price hits 106 your market order will hit the market and you will purchase the stock at 106 or above. You can also place a tack profit order at 107 linked to your initial conditional buy order, so that once you buy order is executed and you buy at 106, a take profit order will be executed only if the price reaches 107 or above.  If the price never reaches 106, neither your market buy order or take profit order will hit the market and you won't buy or sell anything. My thoughts are that if you've seen considerable growth and the profit amassed would be one that makes sense, you would have to seriously consider selling NOW because it could take yeoman's time to mimic that profit in the next 10 quarters or so.  To analogize; If you bought a house for 100k and we're renting it for say 1,000/month and we're making $ 250/month profit and could sell it now for 125k, it would take you 100 months to recoup that $25k profit (or 8 years 4 months). Doesn't it make sense to sell now? You would have that profit NOW and could invest it somewhere else without losing that period of time, and TIME is the emphasis here. I think the advice Bob is being given is good. Bob shouldn't sell his investments just because their price has gone down. Selling cheap is almost never a good idea. In fact, he should do the opposite: When his investments become cheaper, he should buy more of them, or at least hold on to them. Always remember this rule: Buy low, sell high. This might sound illogical at first, why would someone keep an investment that is losing value? Well, the truth is that Bob doesn't lose or gain any money until he sells. If he holds on to his investments, eventually their value will raise again and offset any temporary losses. But if he sells as soon as his investments go down, he makes the temporary losses permanent. If Bob expects his investments to keep going down in the future, naturally he feels tempted to sell them. But a true investor doesn't try to anticipate what the market will do. Trying to anticipate market fluctuations is speculating, not investing. Quoting Benjamin Graham: The most realistic distinction between the investor and the speculator is found in their attitude toward stock-market movements. The speculator's primary interest lies in anticipating and profiting from market fluctuations. The investor's primary interest lies in acquiring and holding suitable securities at suitable prices. Market movements are important to him in a practical sense, because they alternately create low price levels at which he would be wise to buy and high price levels at which he certainly should refrain from buying and probably would be wise to sell. Assuming that the fund in question is well-managed, I would refrain from selling it until it goes up again. "There are two things going on here, neither of which favors this approach. First, as @JohnFx noted, you should be wary of the sunk-cost fallacy, or throwing good money after bad. You already lost the money you lost, and there's no point in trying to ""win it back"" as opposed to just investing the money you still have as wisely as possible, forgetting your former fortune. Furthermore, the specific strategy you suggest is not a good one. The problem is that you're assuming that, whenever the stock hits $2, it will eventually rebound to $3. While that may often happen, it's far from guaranteed. More specifically, assuming the efficient market hypothesis applies (which it almost certainly does), there are theorems that say you can't increase your expected earning with a strategy like the one you propose: the apparent stability of the steady stream of income is offset by the chance that you lose out if the stock does something you didn't anticipate." "If they return to their earlier prices Assuming I don't make too many poor choices That's your problem right there: you have no guarantee that stocks, will in fact return to their earlier prices rather than go down some more after the time you buy them. Your strategy only looks good and easy  in hindsight when you know the exact point in time when stocks stopped going down and started going up. But to implement it, you need to predict that time, and that's impossible. I would adopt a guideline of ""sell when you've made X%, even if it looks like it might go higher."" Congratulations, you've come up with the concept of technical analysis. Now go and read the hundreds of books that have been written about it, then think about why the people who wrote them waste time doing so rather than getting rich by using that knowledge." If you do this, you own a stock worth $1, with a basis of $2. The loss doesn't get realized until the shares are sold. Of course, we hope you see the stock increase above that price, else, why do this? You are assuming the price increase will continue. The people selling are assuming that the price increase will not continue.  Ultimately that's what a share transaction is: one person would rather have the cash at a particular price / time, and one person would rather have the share. If your criteria has changed but some of your existing holdings don't meet your new criteria you should eventually liquidate them, because they are not part of your new strategy. However, you don't want to just liquidate them right now if they are currently performing quite well (share price currently uptrending).  One way you could handle this is to place a trailing stop loss on the stocks that don't meet your current criteria and let the market take you out when the stocks have stopped up trending. Unless you have insider information (ILLEGAL!!!) don't go high risk over this time frame.  It makes about as much sense as betting on the horses. Stick it in a 3 or 6 month GIC at the pathetic rates the banks are giving. "I think the question can be answered by realizing that whoever is buying the stock is buying it from someone who can do the same mathematics. Ask your son to imagine that everyone planned to buy the stock exactly one week before Christmas.  Would the price still be cheap?  The problem is that if everyone knows the price will go up, the people who own it already won't want to sell.  If you're buying something from someone who doesn't really want to sell it, you have to pay more to get it.  So the price goes up a week before Christmas, rather than after Christmas. But of course everyone else can figure this out too.  So they are going to buy 2 weeks before, but that means the price goes up 2 weeks before rather than 1 week.  You play this game over and over, and eventually the expected increased Christmas sales are ""priced in"".  But of course there is a chance people are setting the price based on a mistaken belief. So the winner isn't the person who buys just before the others, but rather the one who can more accurately predict what the sales will be (this is why insider trading is so tempting even if it's illegal).  The price you see right now represents what people anticipate the price will be in the future, what dividends are expected in the future, how much risk people think there is, and how that compares with other available investments." "Check your math... ""two stocks, both with a P/E of 2 trading at $40 per share lets say, and one has an EPS of 5 whereas the other has an EPS of 10 is the latter a better purchase?"" If a stock has P/E of 2 and  price of $40 it has an EPS of $20. Not $10. Not $5."