Is it possible for all the owners of a stock to gain or lose money at the same time?
I'm not sure I understand your question. If the stock price is at an all-time high, everyone who owns the stock is 'in the money'. Of course, they won't actually realise a capital gain until they sell the stock. Similarly, if the stock becomes worthless (the company shuts down after declaring bankruptcy, etc.), everyone who owns the stock is out whatever they paid for the stock. The Owners of stock keep changing with every Buy and Sell. Hence its theoritically possible that everyone makes or loses money. Say the price was $10 when everyone purchased the stock. If the stock is doing good and the markets are good, the stock will move up to $12. Everyone sells the stock to someone else. So all the Old owners have made $2. Now after some period of time, the stock / company is not doing so well, and the markets are bad, so the stock falls to $11, everyone sells. So all the current owners make a loss of $1.   However in normal market conditions, there are Owners who have purchased stock at different price points and have held it irrespective of whether the price has gone above their purchase price or below their purchase price. "Take the case where a stock has just two owners, A and B, both at $10. One of them sells his shares to C, at $11.  Now B has made $1 in profit but is no longer an owner of the stock. A hasn't sold anything but his shares are worth 10% more due to the last traded price printed. C has bought shares at $11 and the price is $11, so technically he hasn't lost any money. In a larger market, there are winners and losers every day on a single stock, but they may not remain owners of a stock. There could be days in which those that remain owners are all winners - say when a stock goes up to an all time high and all those that are currently owners have an average buy price lower than the last traded price. And the reverse applies too.  It is of course more complicated. Say you own a stock and let someone else ""borrow"" it for a short-selling opportunity (he sells it in the market). For each uptick in price, you win, the short seller loses, and the guy he sold it to also wins. A person that has a covered call on a stock is not a winner beyond a point. And so on."
"Oddly enough, in the USA, there are enough cost and tax savings between buy-and-hold of a static portfolio and buying into a fund that a few brokerages have sprung up around the concept, such as FolioFN, to make it easier for small investors to manage numerous small holdings via fractional shares and no commission window trades. A static buy-and-hold portfolio of stocks can be had for a few dollars per trade.  Buying into a fund involves various annual and one time fees that are quoted as percentages of the investment.  Even 1-2% can be a lot, especially if it is every year.  Typically, a US mutual fund must send out a 1099 tax form to each investor, stating that investors share of the dividends and capital gains for each year. The true impact of this is not obvious until you get a tax bill for gains that you did not enjoy, which can happen when you buy into a fund late in the year that has realized capital gains.  What fund investors sometimes fail to appreciate is that they are taxed both on their own holding period of fund shares and the fund's capital gains distributions determined by the fund's holding period of its investments. For example, if ABC tech fund bought Google stock several years ago for $100/share, and sold it for $500/share in the same year you bought into the ABC fund, then you will receive a ""capital gains distribution"" on your 1099 that will include some dollar amount, which is considered your share of that long-term profit for tax purposes. The amount is not customized for your holding period, capital gains are distributed pro-rata among all current fund shareholders as of the ex-distribution date. Morningstar tracks this as Potential Capital Gains Exposure and so there is a way to check this possibility before investing. Funds who have unsold losers in their portfolio are also affected by these same rules, have been called ""free rides"" because those funds, if they find some winners, will have losers that they can sell simultaneously with the winners to remain tax neutral.  See ""On the Lookout for Tax Traps and Free Riders"", Morningstar, pdf In contrast, buying-and-holding a portfolio does not attract any capital gains taxes until the stocks in the portfolio are sold at a profit.  A fund often is actively managed.  That is, experts will alter the portfolio from time to time or advise the fund to buy or sell particular investments. Note however, that even the experts are required to tell you that ""past performance is no guarantee of future results.""" The stock market is no different in this respect to anything that's bought or sold. The price of a stock like many other things reflects what the seller is prepared to sell it at and what the buyer is prepared to offer for it. If those things match then a transaction can take place. The seller loses money but gains stocks they feel represent equivalent value, the reverse happens for the buyer. Take buying a house for example, did the buyer lose money when they bought a house, sure they did but they gained a house. The seller gained money but lost a house. New money is created in the sense that companies can and do make profits, those profits, together with the expected profits from future years increase the value that is put on the company. If we take something simple like a mining company then its value represents a lot of things: and numerous other lesser things too. The value of shares in the mining company will reflect all of these things. It likely rises and falls in line with the price of the raw materials it mines and those change based on the overall supply and demand for those raw materials. Stocks do have an inherent value, they are ownership of a part of a company. You own part of the asset value, profits and losses made by that company. Betting on things is different in that you've no ownership of the thing you bet on, you're only dependent on the outcome of the bet. Would you mind adding where that additional value comes from, if not from the losses of other investors?  You asked this in a comment, but it seems to be the key to the confusion.   Corporations generate money (profits, paid as dividends) from sales.  Sales trade products for money.  The creation of the product creates value.  A car is worth more than General Motors pays for its components and inputs, even including labor and overhead as inputs.  That's what profit is:  added value.  The dividend is the return that the stock owner gets for owning the stock.   This can be a bit confusing in the sense that some stocks don't pay dividends.  The theory is that the stock price is still based on the future dividends (or the liquidation price, which you could also consider a type of dividend).  But the current price is mostly based on the likelihood that the stock price will increase rather than any expected dividends during ownership of the stock.   A comment calls out the example of Berkshire Hathaway.  Berkshire Hathaway is a weird case.  It operates more like a mutual fund than a company.  As such, investors prefer that it reinvest its money rather than pay a dividend.  If investors want money from it, they sell shares to other investors.  But that still isn't really a zero sum game, as the stock increases in value over time.   There are other stocks that don't pay dividends.  For example, Digital Equipment Corporation went through its entire existence without ever paying a dividend.  It merged with Compaq, paying investors for owning the stock.   Overall, you can see this in that the stock market goes up on average.  It might have a few losing years, but pick a long enough time frame, and the market will increase during it.  If you sell a stock today, it's because you value the money more than the stock.  If it goes up tomorrow, that's the buyer's good luck.  If it goes down, the buyer's bad luck.  But it shouldn't matter to you.  You wanted money for something.  You received the money.   The increase in the stock market overall is an increase in value.  It is completely unrelated to trading losses.  Over time, trading gains outweigh trading losses for investors as a group.  Individual investors may depart from that, but the overall gain is added value.   If the only way to make gains in the stock market was for someone else to take a loss, then the stock market wouldn't be able to go up.  To view it as a zero sum game, we have to ignore the stocks themselves.  Then each transaction is a payment (loss) for one party and a receipt (gain) for the other.  But the stocks themselves do have value other than what we pay for them.  The net present value of of future payments (dividends, buyouts, etc.) has an intrinsic worth.  It's a risky worth.  Some stocks will turn out to be worthless, but on average the gains outweigh the losses. When you invest in stocks, there are two possible ways to make money: Many people speculate just on the stock price, which would result in a gain (or loss), but only once you have resold the shares. Others don't really care about the stock price. They get dividends every so often, and hopefully, the return will be better than other types of investments. If you're in there for the long run, you do not really care what the price of the stock is. It is often highly volatile, and often completely disconnected from anything, so it's not because today you have a theoretical gain (because the current stock price is higher than your buying price) that you will effectively realise that gain when you sell (need I enumerate the numerous crashes that prevented this from happening?). Returns will often be more spectacular on share resale than on dividends, but it goes both ways (you can lose a lot if you resell at the wrong time). Dividends tend to be a bit more stable, and unless the company goes bankrupt (or a few other unfortunate events), you still hold shares in the company even if the price goes down, and you could still get dividends. And you can still resell the stock on top of that! Of course, not all companies distribute dividends. In that case, you only have the hope of reselling at a higher price (or that the company will distribute dividends in the future). Welcome to the next bubble... No, at least not noticeably so. The majority of what HFT does is to take advantage of the fact that there is a spread between buy and sell orders on the exchange, and to instantly fill both orders, gaining relatively risk-free profit from some inherent inefficiencies in how the market prices stocks. The end result is that intraday trading of the non-HFT nature, as well as speculative short-term trading will be less profitable, since HFT will cause the buy/sell spread to be closer than it would otherwise be. Buying and holding will be (largely) unaffected since the spread that HFT takes advantage of is miniscule compared to the gains a stock will experience over time.  For example, when you go to buy shares intending to hold them for a long time, the HFT might cost you say, 1 to 2 cents per share. When you go to sell the share, HFT might cost you the same again. But, if you held it for a long time, the share might have doubled or tripled in value over the time you held it, so the overall effect of that 2-4 cents per share lost from HFT is negligible. However, since the HFT is doing this millions of times per day, that 1 cent (or more commonly a fraction of a cent) adds up to HFTs making millions. Individually it doesn't affect anyone that much, but collectively it represents a huge loss of value, and whether this is acceptable or not is still a subject of much debate! Alot of these answers have focused on the dilution aspect, but from a purely legal aspect, there are usually corporate bylaws that spell out what kind of vote and percentage of votes is needed to take this type of action.  If all other holders of stock voted to do this, so 90% for, and you didn't, so 10% against, it's still legal if that vote meets the threshold for taking the action. As an example of this, I known of a startup where employees got $0/share for their vested shares when the company was sold because the voting stock holders agreed to it.  Effectively the purchase amount was just enough to cover debts and preferred stock. "Yes, the value of a stock is completely, 100% determined by what people are willing to pay for it in conjunction with what people who have it are willing to sell it for. If something really bad happened to a company, like their only factory burned to the ground, and the traders didn't care, then I guess, in that scenario, the value of the stock would not change. But you can spin all sorts of hypotheticals of that sort. If dogs could talk, would German Shepherds speak German? Etc. Any answer is pretty meaningless because the premise is wildly unlikely. As CQM notes, ""traders"" in this context means everyone who buys or sells stock. If you buy stock, that includes you. They're not some mystical cabal somewhere. If you see a stock listed at, whatever, $50, and you are not willing to pay more than $40 for it, then you refuse to buy, and so you tend to force the price down. If you're not a billionaire, then your impact on the market is tiny, but the market is made up of millions of people each with tiny influence. Note that all this is true not just of the stock market, but of every product on the market. A product is worth whatever the owner is willing to sell it for and people are willing to pay. This is what determines the price of everything from houses to toasters. It's a little theory I've invented that I like to call, ""the law of supply and demand"". :-)" "You can certainly try to do this, but it's risky and very expensive. Consider a simplified example. You buy 1000 shares of ABC at $1.00 each, with the intention of selling them all when the price reaches $1.01. Rinse and repeat, right? You might think the example above will net you a tidy $10 profit. But you have to factor in trade commissions. Most brokerages are going to charge you per trade. Fidelity for example, want $4.95 per trade; that's for both the buying and the selling. So your 1000 shares actually cost you $1004.95, and then when you sell them for $1.01 each, they take their $4.95 fee again, leaving you with a measly $1.10 in profit. Meanwhile, your entire $1000 stake was at risk of never making ANY profit - you may have been unlucky enough to buy at the stock's peak price before a slow (or even fast) decline towards eventual bankruptcy.  The other problem with this is that you need a stock that is both stable and volatile at the same time. You need the volatility to ensure the price keeps swinging between your buy and sell thresholds, over and over again. You need stability to ensure it doesn't move well away from those thresholds altogether. If it doesn't have this weird stable-volatility thing, then you are shooting yourself in the foot by not holding the stock for longer: why sell for $1.01 if it goes up to $1.10 ten minutes later? Why buy for $1.00 when it keeps dropping to $0.95 ten minutes later? Your strategy means you are always taking the smallest possible profit, for the same amount of risk. Another method might be to only trade each stock once, and hope that you never pick a loser. Perhaps look for something that has been steadily climbing in price, buy, make your tiny profit, then move on to the next company. However you still have the risk of buying something at it's peak price and being in for an awfully long wait before you can cash out (if ever). And if all that wasn't enough to put you off, brokerages have special rules for ""frequent traders"" that just make it all the more complicated. Not worth the hassle IMO."