If throwing good money after bad is generally a bad idea, is throwing more money after good Ok?
"The response to this question will be different depending which of the investment philosophies you are using.  Value investors look at the situation the company is in and try to determine what the company is worth and what it will be worth in the future. Then they look at the current stock price and decide whether or not the stock is priced at a good deal or not. If the stock price is priced lower than they believe the company is worth, they would want to buy stock, and if the price rises above what they believe to be the true value, they would sell. These types of investors are not looking at the history or trend of what the price has done in the past, only what the current price is and where they believe the price should be in the future.  Technical analysis investors do something different. It is their belief that as stock prices go up and down, they generally follow patterns. By looking at a chart of what a stock price has been in the past, they try to predict where it is headed, and buy or sell based on that prediction.  In general, value investors are longer-term investors, and technical analysis investors are short-term investors.  The advice you are considering makes a lot of sense if you are using technical analysis. If you have a stock that is trending down, your strategy probably tells you to sell; buying more in the hopes of turning things around would be seen as a mistake. It is like the gambler in Vegas who keeps playing a game he is losing, hoping that his luck changes.  However, for the value investor, the historical price of a stock, and even the amount you currently have gained or lost in the stock, are essentially ignored. All that matters is whether or not the stock price is above or below the true value determined by the investor. For him, if the stock price falls and he believes the company still has a high value, it could be a signal to buy more. The above advice doesn't really apply for them.  Many investors don't follow either of these strategies. They believe that it is too difficult and risky to try to predict the future price of an individual stock. Instead, they invest in many companies all at once using index mutual funds, believing that the stock market as a whole always heads up over a long time frame. Those investors don't care at all if the prices of stock are going up or down. They simply keep investing each month, and hold until they have another use for the money. The above advice isn't useful for them at all.  No matter which kind of investing you are doing, the most important thing is to pick a strategy you believe in and follow the plan without emotion. Emotions can cause investors to make mistakes and start buying when their strategy tells them to sell.  Instead of trying to follow fortune cookie advice like ""Don't throw good money after bad,"" choose an investment strategy, make a plan, test it, and follow it, cautiously (after all, it may be a bad plan). For what it is worth, I am the third type of investor listed above. I don't buy individual stocks, and I don't look at the stock prices when investing more each month. Your description of your own strategy as ""buy and hold"" suggests you might prefer the same approach." "I have heard that investing more money into an investment which has   gone down is generally a bad idea*. ""Throwing good money after bad"" so   to speak. Is investing more money into a stock, you already have a stake in,   which has gone up in price; a good idea? Other things being equal, deciding whether to buy more stocks or shares in a company you're already invested in should be made in the same way you would evaluate any investment decision and -- broadly speaking -- should not be influenced by whether an existing holding has gone up or down in value. For instance, given the current price of the stock, prevailing market conditions, and knowledge about the company, if you think there is a reasonable chance that the price will rise in the time-period you are interested in, then you may want to buy (more) stock. If you think there is a reasonable chance the price will fall, then you probably won't want to buy (more) stock. Note: it may be that the past performance of a company is factored into your decision to buy (e.g was a recent downturn merely a ""blip"", and long-term prospects remain good; or have recent steady rises exhausted the potential for growth for the time being). And while this past performance will have played a part in whether any existing holding went up or down in value, it should only be the past performance -- not whether or not you've gained or lost money -- that affects the new decision. For instance: let us suppose (for reasons that seemed valid at the time) you bought your original holding at £10/share, the price has dropped to £2/share, but you (now) believe both prices were/are ""wrong"" and that the ""true price"" should be around £5/share. If you feel there is a good chance of this being achieved then buying shares at £2, anticipating they'll rally to £5, may be sound. But you should be doing this because you think the price will rise to £5, and not because it will offset the loses in your original holding. (You may also want to take stock and evaluate why you thought it a good idea to buy at £10... if you were overly optimistic then, you should probably be asking yourself whether your current decisions (in this or any share) are ""sound""). There is one area where an existing holding does come into play: as both jamesqf and Victor rightly point out, keeping a ""balanced"" portfolio -- without putting ""all your eggs in one basket"" -- is generally sound advice. So when considering the purchase of additional stock in a company you are already invested in, remember to look at the combined total (old and new) when evaluating how the (potential) purchase will affect your overall portfolio." "I have heard that investing more money into an investment which has gone down is generally a bad idea*. ""Throwing good money after bad"" so to speak. This is over simplified statement to explain the concept. What is essentially says is; Say I hold stocks of XYZ; 100 units worth say USD 1000. This has lost me x% [say 50%]. The general tendency is to buy 100 more units in anticipation / hope that the price will go up. This is incorrect.  However on case to case basis, this maybe the right decisions. On a periodic basis [or whenever you want to invest more money]; say you have USD 1000 and did not have the stock of XYZ, will you buy this at current price and outlook of the company. If the answer is Yes, hold the stock [or buy more], if the answer is no sell the stock at current market price and take the loss. The same applies when the price has appreciated. If you have USD 1000; given the current price and future outlook, will you buy the specific stock. If yes, hold the stock [or buy more], if answer is no sell the stock and book profit. Off-course I have not overlaid the various other considerations when buying stocks like diversification, risk profiles of individual stocks / segments, tax implications etc that are also essential even if you decide to buy or sell specific stock." The principle behind the advice to not throw good money after bad is better restated in economics terms: sunk costs are sunk and irrelevant to today's decisions.   Money lost on a stock is sunk and should not affect our decisions today, one way or the other.  Similarly, the stock going up should not affect our decisions today, one way or the other.  Any advice other than this is assuming some kind of mispricing or predictability in the market.  Mispricings in general cannot be reliably identified and stock returns are not normally predictable. The only valid (efficient markets) reason I know of to allow money you have lost or made on a stock to affect your decision today is the tax implications (you may want to lock in gains if your tax rate is temporarily low or vice versa). To expand a bit on what TripeHound said in the comment section, past performance is not indicative of future performance, which is why the best advice is to ignore if you already own the stock or not.  If the stock goes down, but you've done your research and think it will come back, then investing more isn't a bad idea. If the stock is doing well and it will continue to do well, then invest more. Treat investing more into a stock you already own as a new investment and do your research.  TL;DR of your question, it's a very case-by-case basis Is investing more money into a stock that you already have a stake, in which has gone up in price a good idea? What you describe here is a good idea when the stock keeps up-trending. The way to do it is say you have originally bought $1000 worth of shares, then the next purchase you buy $500 worth, then $250 worth. It is called pyramiding into your trades. However, this system would not be the best with simply a buy and hold when you keep holding even if the price starts freefalling. You would need to have a trailing stop loss on your initial trade, and then as you buy each additional trade your trailing stop loss would incorporate the additional trade and move to a level where if you get stopped out you will make an overall profit. With each additional trade your trailing stop will move higher and higher for higher protected profits. The whole point behind pyramid trading is to keep buying more of a stock that keeps performing well to increase your profits. However, each additional purchase is half the previous one so that you don't eat too much into existing profits (in the case of the uptrend reversing) and so as to not overcapitalise on the one stock. So you are using part of your existing profits in an attempt to make more profits.
"I love John's answer, but I just can't help myself from adding my 2 cents, even though it's over 5 years later. I sold cars for a while in the late 90s, and I mostly agree with John's answer. Where I disagree though, is that where I worked, the salesperson did not have ANY authority to make a sale. A sales manager was required to sign off on every sale. That doesn't mean that the manager had to interact with the buyer, that could all be handled behind the scenes, but the pricing and even much of the negotiating strategies were dictated by the sales managers. Some of the seasoned salespeople would estimate numbers on their own, but occasionally you'd hear the managers still chew them out with ""I wish you wouldn't have said that"". Of course, every dealership is different. Additional purchase advice: There is a strategy that can work well for the buyer, but only in scenarios where the salesperson is trying to prevent you from leaving. They may start interrupting you as you are packing up, or blocking your path to the door, or even begging. If this happens, they are obviously desperate for whatever reason. In this case, if you came prepared with research on a good price that you are comfortable with, then shoot lower and hold firm to the point of near exhaustion. Not so low that that they realize you're too far away- they will let you leave at that point. It needs to be within a reasonable amount, perhaps at most 1-2% of the purchase price. Once you detect the salesperson is desperate, you finally move up to your goal number or possibly a little lower. Typically the salesperson will be so happy to have gotten you to move at all that they'll accept. And if the managers are fed up too (like 45 minutes after close), they'll accept too. I saw this happen multiple times in a high pressure scenario. I also used it once myself as a buyer. If you are planning to purchase options that can be added at the dealer rather than from the factory, keep them up your sleeve at first. Get your negotiations down to where you are a little further apart than the invoice price of the option, then make your move. For example, suppose the option you want retails for $350 with an invoice of $300. Get within about $400 of the dealer. Then offer to pay their price, but only if they throw in the option you want. This will throw them completely off guard because they didn't expect it and all of their calculations were based on without it. If they say yes, you effectively moved $100 and they moved $300. It's much more likely that they'll agree to this than taking $300 off the price of the car. (I'm guessing the reason for this is partially due to how their accounting works with sticker price vs aftermarket price, and partially psychological.) Note, this works best with new cars, and make sure you only do this if it's for items they can add after the fact. Even if they don't have the part in stock it's ok, they can give you an IOU. But if the option requires a car change to something they don't have on the lot, it will probably just make them mad." One major concern with moving out on your own is can you afford rent each month, be it an apartment or a house payment. You'll hear people say that anywhere from 25% to 40% of your monthly after-tax income should go to housing. 40% seems very high to me and quite risky. I'd go for closer to 30% of your monthly after-tax income and not any higher, but that's just my opinion.  I had a friend that moved out of his parents house about the same time that I did. He bought himself a house, and then he immediately started looking for roommates to help pay for his house. It really was a good idea, and I wish that I'd been in a position to do the same, because I'm sure that it saved him a lot of money for the first couple of years. Apart from that, my only advise would be to get a house if you can afford it. 1) Interest rates are very low right now, and 2) if you're paying rent to someone (for an apartment or whatever) then you're just throwing your hard-earned money away. Good luck! "If I buy property when the market is in a downtrend the property loses   value, but I would lose money on rent anyway. So, as long I'm viewing   the property as housing expense I would be ok. This is a bit too rough an analysis.  It all depends on the numbers you plug in.  Let's say you live in the Boston area, and you buy a house during a downtrend at $550k.  Two years later, you need to sell it, and the best you can get is $480k.  You are down $70k and you are also out two years' of property taxes, maintenance, insurance, mortgage interest maybe, etc.  Say that's another $10k a year, so you are down $70k + $20k = $90k.  It's probably more than that, but let's go with it... In those same two years, you could have been living in a fairly nice apartment for $2,000/mo.  In that scenario, you are out $2k * 24 months = $48k--and that's it.  It's a difference of $90k - $48k = $42k in two years.  That's sizable. If I wanted to sell and upgrade to a larger property, the larger   property would also be cheaper in the downtrend. Yes, the general rule is:  if you have to spend your money on a purchase, it's best to buy when things are low, so you maximize your value.   However, if the market is in an uptrend, selling the property would   gain me more than what I paid, but larger houses would also have   increased in price. But it may not scale.  When you jump to a much larger (more expensive) house, you can think of it as buying 1.5 houses.  That extra 0.5 of a house is a new purchase, and if you buy when prices are high (relative to other economic indicators, like salaries and rents), you are not doing as well as when you buy when they are low.   Do both of these scenarios negate the pro/cons of buying in either   market? I don't think so.  I think, in general, buying ""more house"" (either going from an apartment to a house or from a small house to a bigger house) when housing is cheaper is favorable.  Houses are goods like anything else, and when supply is high (after overproduction of them) and demand is low (during bad economic times), deals can be found relative to other times when the opposite applies, or during housing bubbles.   The other point is, as with any trend, you only know the future of the trend...after it passes.  You don't know if you are buying at anything close to the bottom of a trend, though you can certainly see it is lower than it once was.   In terms of practical matters, if you are going to buy when it's up, you hope you sell when it's up, too. This graph of historical inflation-adjusted housing prices is helpful to that point:  let me just say that if I bought in the latest boom, I sure hope I sold during that boom, too!" "Serious answer: This would be a horrible idea for you, so don't do it.  Theoretical answer:  This gets more complicated.  If you are refusing to pay your student loans, this is bad for the economy because you just destroyed the value associated with that payment.  You essentially robbed the person holding the debt (since you promised to pay it off).    However, you also stimulate the economy by buying goods.  I'm just an armchair economist, but I would say that the detriment of not paying your debt is higher than the benefit of paying for the goods.  Now, lets say you never say your not paying of your loans, and instead just pay the minimum payment and buy the goods.  Now you are helping the economy because your debt is still generating money *and* you are injecting real money through your payment.  So you essentially made more money for the economy.  So long as the ""system"" believes you can pay of the debt, the ""system"" is able to hold more money.  This is actually why most credit companies *want* you to pay the minimum balance (that, and the interest earns them far more money than you borrowed)." Any investor can make a bad bet, even Buffett. Even if you have done every bit of research on an investment possible you are exposed to random external events.. acts of god, and outright fraud. Someone entering a casino with $15 could employ a very simple strategy and have a better-than-90% chance of walking out with $16.  Unfortunately, the person would have a non-trivial chance (about one in 14) of walking out with $0. If after losing $15 the person withdrew $240 from the bank and tried to win $16, the person would have a better-than-90% chance of succeeding and ending up ahead (holding the original $15, plus the additional $240, plus $1) but would have at that point about a one in 14 chance from that point of losing the $240 along with the original $15.  Measured from the starting point, you'd have about a 199 out of 200 chance of gaining $1, and a one out of 200 chance of losing $240. Market-timing bets are like that.  You can arrange things so you have a significant chance of making a small profit, but at the risk of a large downside.  If you haven't firmly decided exactly how much downside you are willing to accept, it's very easy to simultaneously believe you don't have much money at risk, but that you'll be able to win back anything you lose.  The only way you can hope to win back anything you lose is by bringing a lot more money to the table, which will of course greatly increase your downside risk. The probability of making money for the person willing to accept $15 of downside risk to earn $1 is about 93%.  The probability of making money for the person willing to accept $255 worth of risk is about 99.5%.  It's easy to see that there are ways of playing which have a 99.5% chance of winning, and that there are ways of playing that only have a 15:1 downside risk.  Unfortunately, the ways of playing that have the smaller risk don't have anything near a 99.9% chance of winning, and those that have a better chance of winning have a much larger downside risk. ...is investing in a business you believe in a bad strategy?   I'm not saying you're going to be right with your investment (obviously your judgment is coming into play), but you make it sound like it's a terrible way to do things. Is it? What you're describing is called timing the market.  That is, if you correctly predict when the market will drop, you can sell before the drop, wait for the drop, then buy after the drop has occurred.  Sell high, buy low. The fundamental problem with that, though, is: What ends up happening, on average, is you end up slightly behind.  There's quite a lot of literature on this; see Betterment's explanation for example.  Forbes (click through ad first) also has a detailed piece on the matter. Now, we're not really talking HFT issues here; and there are some structural things that some argue you can take advantage of (restrictions on some organizational investors, for example, similar to a blackjack dealer who has to hit on 16).  However, everyone else knows about these too - so it's hard to gain much of an edge. Plenty of people say they can time the market right, and even yourself perhaps you timed a particular drop accurately.  This tends to lead to false confidence though; how many drops that you timed badly do you remember? Ultimately, most investors end up slightly down when they attempt to time the market, because of the transaction costs (if you guess two drops, one 'right' and one 'wrong', and they have exactly opposite gains/losses before commissions, you will lose a bit on each due to commission), and because of the overall upward trend in the market (ie, if you picked at random one month a year to be out of the market, you'd lose around 10% annualized gains from doing that; same applies here). All of that aside, there is one major caveat: risk tolerance.  If you are highly risk tolerant, say a 30 year old investing your 401(k), then you should stay in no matter what.  If you're not - say you're 58 and retiring in a few years - then knowledge that there's a higher risk time period coming up might suggest moving to a less risky portfolio, even at the known cost of some gains.