What happens when there are no Limit Orders?
The obvious thing would happen. 10 shares change owner at the price of $100. A partially still open selling order would remain. Market orders without limits means to buy or sell at the best possible or current price. However, this is not very realistic. Usually there is a spread between the bid and the ask price and the reason is that market makers are acting in between. They would immediately exploit this situation, for example, by placing appropriately limited orders. Orders without limits are not advisable for stocks with low trading activity. Would you buy or sell stuff without caring for the price?
The options market requires much more attention to avoid the situation you're describing. An overnight $10 ask will remain on the books most likely as Good-Til-Canceled.  The first to bid the low order gets it.  If traders are paying attention, which they probably are then they will bid at $10.  If not, they will bid immediately at $20. If they crossed the order, it would be filled at their higher than $10 bid. This is all governed by the exchange where the ask is posted, and most implement price-time priority. "You can choose to place successively lower buy limit orders, but whether they get filled or not is not a given; it depends on whether sellers care to accept your bid. In your example of a 49.98 / 50.01 spread, if you place a buy with limit of 49.99, it won't get filled (if the order reaches the market while still at 49.98 / 50.01) immediately, but will be added to the order book.  By being added to the order book, the markets bid and ask become 49.99 / 50.01.  Your order won't get filled until some seller places a market order or a sell limit order of 49.99 or less.  No guarantee that that will happen, and even if it does, there's nothing to say that your follow-up buy at 49.98 will ever be filled.  In fact, your 49.98 buy order queues up at the ""end of the line"" behind all previously pending 49.98 bids, since your order arrived after those other bids.  Since the initial conditions you supposed had a 49.98 bid, such an order exists (or at least did exist; it might have been cancelled in the intervening moment. Basically, your first buy at 49.99, if it happens, has essentially no influence on whether your second buy at 49.98 will happen.  You can't expect to move the market lower by making a bid that is higher (49.99) than the existing best bid (49.98).  Whatever influence your 49.99 order has is to raise the market's price, not lower it." TD will only sell the stock for you if there's a buyer. There was a buyer, for at least one transaction of at least one stock at 96.66. But who said there were more? Obviously, the stocks later fell, i.e.: there were not that many buyers as there were sellers. What I'm saying is that once the stock passed/reached the limit, the order becomes an active order. But it doesn't become the only active order. It is added to the list, and to the bottom of that list. Obviously, in this case, there were not enough buyers to go through the whole list and get to your order, and since it was a limit order - it would only execute with the limit price you put. Once the price went down you got out of luck.  That said, there could of course be a possibility of a system failure. But given the story of the market behavior - it just looks like you miscalculated and lost on a bet. It depends on how you place your stop order and the type of stop orders available from your broker. If you place a stop market order and the following day the stock opens below your stop your stock will be stopped out at or around the opening price, meaning you can potentially end up with quite a large gap. If you place a stop limit order, say you place your stop at $10.00 with a limit price of $9.90, and if the price opens below $9.90, say at $9.50, your limit sell order of $9.90 will be placed onto the market but it will not be executed until the price goes back up to $9.90 or above. The third option is to place a Guaranteed Stop Loss, and as specified you are guaranteed your stop price even if the price gaps down below your stop price. You will be paying an extra fee for the Guaranteed Stop Loss Order, and they are usually mainly available with CFD Brokers (so if you are in the USA you might be out of luck). A limit order is simply an order to buy at a maximum price or sell at a minimum price. For example, if the price is $100 and you want to sell if the price rises to $110, then you can simply put a limit order to sell at $110. The order will be placed in the market and when the price reaches $110 your order will be executed. If the price gaps at the open to $111, then you would end up selling for $111. In other words you will get a minimum of $110 per share. A stop limit order is where you put a stop loss order, which when it gets triggered, will place a limit order in the market for you. For example, you want to limit your losses by placing a stop loss order if the price drops to $90. If you chose a market order with your stop loss as soon as the price hits $90 your stop loss would be triggered and the shares would sell at the next available price, usually at $90, but could be less if the market gaps down past $90. If on the other hand you placed a limit order at $89.50 with your stop loss, when the stop loss order gets triggered at $90 your limit order will be placed into the market to sell at $89.50. So you would get a minimum of $89.50 per share, however, if the market gaps down below $89.50 your order will be placed onto the market but it won't sell, unless the price goes back to or above $89.50. Hope this helps. But what about the following scenario which is my paraphrasing of a Nanex article (I'm hoping you can help clarify this for me).  1. I observe a 1,000 lot @$10 advertised for Sell on a lit exchange.  2. I try to lift the 1,000 by placing a limit order @10.  3. My order goes through some kind of order routing process. First, 3 orders get executed on a dark pool. Let's say I got a 50 lot filled (so available offer reduces to 950).  4. My order hits a lit exchange. I get a partial fill for 100 (offer shrinks to 850); but the offered size shrinks instead to 500. Or 0.  5. Now, in order to execute my trade, I will have to take a higher price than the original advertised liquidity.  My question (maybe you can answer this) is why did my original order size of 1,000 appear in smaller blocks? Is this because the order routing algorithm breaks up the size?  Or is it that market makers only post offers in small block sizes (e.g. 100) So even if the order book looked like:  100 @ 10  100 @ 10  100 @ 10  100 @ 10  100 @ 10  100 @ 10  All the way to 1,000 total -- as soon as the first 100 shares were lifted, the MM can immediately cancel the remainder of the advertised liquidity -- in practical terms making it impossible to execute large orders at an advertised price. You can do FOK on both market and limit orders. Normal market orders will partial fill if you want more shares than are being offered, or if someone pulled their order before you get there and now there are fewer shares than you placed a trade for. With a FOK limit order not at the BBO you are shooting in the dark for a quick match, most of the time it does not fill.  This is a commonly used order type for UHFT arbitrage.  Some exchanges will not attempt to cross it for a match if its price is not at, or better than the market price. When the FOK limit order is at the BBO it is essentially a FOK market order.   FYI: Sometimes you have a minimum quantity to fill option, so you can let the order sit on the book until it fills or you cancel. "There are two distinct questions that may be of interest to you. Both questions are relevant for funds that need to buy or sell large orders that you are talking about. The answer depends on your order type and the current market state such as the level 2 order book. Suppose there are no iceberg or hidden orders and the order book (image courtesy of this question) currently is:  An unlimited (""at market"") buy order for 12,000 shares gets filled immediately: it gets 1,100 shares at 180.03 (1,100@180.03), 9,700 at 180.04 and 1,200 at 180.05. After this order, the lowest ask price becomes 180.05 and the highest bid is obviously still 180.02 (because the previous order was a 'market order'). A limited buy order for 12,000 shares with a price limit of 180.04 gets the first two fills just like the market order: 1,100 shares at 180.03 and 9,700 at 180.04. However, the remainder of the order will establish a new bid price level for 1,200 shares at 180.04. It is possible to enter an unlimited buy order that exhausts the book. However, such a trade would often be considered a mis-trade and either (i) be cancelled by the broker, (ii) be cancelled or undone by the exchange, or (iii) hit the maximum price move a stock is allowed per day (""limit up""). Funds and banks often have to buy or sell large quantities, just like you have described. However they usually do not punch through order book levels as I described before. Instead they would spread out the order over time and buy a smaller quantity several times throughout the day. Simple algorithms attempt to get a price close to the time-weighted average price (TWAP) or volume-weighted average price (VWAP) and would buy a smaller amount every N minutes. Despite splitting the order into smaller pieces the price usually moves against the trader for many reasons. There are many models to estimate the market impact of an order before executing it and many brokers have their own model, for example Deutsche Bank. There is considerable research on ""market impact"" if you are interested. I understand the general principal that when significant buy orders   comes in relative to the sell orders price goes up and when a   significant sell order comes in relative to buy orders it goes down. I consider this statement wrong or at least misleading. First, stocks can jump in price without or with very little volume. Consider a company that releases a negative earnings surprise over night. On the next day the stock may open 20% lower without any orders having matched for any price in between. The price moved because the perception of the stocks value changed, not because of buy or sell pressure. Second, buy and sell pressure have an effect on the price because of the underlying reason, and not necessarily/only because of the mechanics of the market. Assume you were prepared to sell HyperNanoTech stock, but suddenly there's a lot of buzz and your colleagues are talking about buying it. Would you still sell it for the same price? I wouldn't. I would try to find out how much they are prepared to buy it for. In other words, buy pressure can be the consequence of successful marketing of the stock and the marketing buzz is what changes the price." Obvious answer but the limit order should be set at the price that you are willing to pay :). More usefully, if you want a decent chance of the order filling in short notice you should place the order one price tick above the current highest buyer (bid price). As long as high frequency trading remains alive I would advise against ever using market orders, these algorithmic trades can occasionally severely distort the price of a security in a fraction of a second. So if your market order happens to fill in during such a distortion you might end up massively overpaying/underselling. "That article, like almost any article written by a non-expert and quoting only ""research"" from lobbying groups, hugely misses the point. The vast majority of orders that end up being cancelled are cancelled as a standard part of exchanges' official market-maker programs. Each exchange wants you and me to know that it has liquidity -- that when we go to buy or sell some stock, there will be someone waiting on the other side of the trade.  So the exchange pays (via lowered fees or even rebates) hundreds of registered market makers to constantly have orders resting in each product's order book within a few ticks of the current NBBO or the last trade price.  That way, if everyone else should suddenly disappear from the market, you and I will still be able to trade our shares for a price somewhat close to the last trade price. But market makers who are simply acting in this ""backstop"" role don't actually want to have their orders filled, because those orders will almost always lose them money. So as prices rise and fall (as much as tens of times per second), the market makers need to cancel their resting orders (so they don't get filled) and add new ones at new prices (so they meet their obligations to the exchange).  And because the number of orders resting in any given product's order book is vastly larger than the number of actual trades that take place in any given time period, naturally the number of cancellations is also going to hugely outweigh the number of actual trades.  As much as 97% to 3% (or even more). But that's completely fine! You and I don't have to care about any of that.  We almost never need the market makers to be there to trade with us.  They're only there as a backstop.  There's almost always plenty of organic liquidity for us to trade against.  Only in the rare case where liquidity completely dries up do we really care that the registered market makers are there.  And in those cases (ideally) the market makers can't cancel their orders (depending on how well the exchange has set up its market maker program). So, to answer your question, the effect of standard order cancellation on a stock is essentially none.  If you were to visualize the resting orders in a product's book as prices moved up and down, you would essentially see a Gaussian distribution with mean at the last trade price, and it would move up and down with the price.  That ""movement"" is accomplished by cancellations followed by new orders. P.S. As always, keep in mind that your and my orders almost never actually make it to a real stock exchange anymore.  Nowadays they are almost always sent to brokers' and big banks' internal dark pools.  And in there you and I have no idea what shenanigans are going on.  As just one example, dark pools allow their operators and (for a fee) other institutional participants access to a feature called last look that allows them to cancel their resting order as late as after your order has been matched against it! :( Regarding the question in your comment ... If Alice is sending only bona fide orders (that is, only placing an order at time T if, given all the information she has at time T, she truly wants and intends for it to be filled) then her cancellation at a later time actually adds to the effectiveness of and public perception of the market as a tool for price discovery (which is its ultimate purpose). [In the following example imagine that there are no such things as trading fees or commissions or taxes.] Let's say Alice offers to buy AAPL at $99.99 when the rest of the market is trading it for $100.00.  By doing so she is casting her vote that the ""fair value"" of a share of AAPL is between $99.99 and $100.00. After all, if she thought the fair value of a share of AAPL was higher --  say, between $100.00 and $100.01 -- then she should be willing to pay $100.00 (because that's below fair value) and she should expect that other people in the market will not soon decide to sell to her at $99.99. If some time later Alice does decide that the fair value of AAPL is between $100.00 and $100.01 then she should definitely cancel her order at $99.99, for exactly the reason discussed above.  She probably won't get filled at $99.99, and by sitting there stubbornly she's missing out (potentially forever) on the possibility to make a profit. Through the simple act of cancelling her $99.99 order, Alice is once again casting a vote that she no longer thinks that's AAPL's fair value.  She is (very slightly) altering the collective opinion of the entire market as to what a share of AAPL is worth.  And if her cancellation then frees her up to place another order closer to her perceived fair value (say, at $100.00), then that's another vote for her honest optinion about AAPL's price. Since the whole goal of the market is to get a bunch of particpants to figure out the fair value of some financial instrument (or commodity, or smart phone, or advertising time, etc.), cancellations of honest votes from the past in order to replace them with new, better-informed honest votes in the present can only be a good thing for the market's effectiveness and perceived effectiveness. It's only when participants start sending non-honest votes (non bona fide orders) that things start to go off the rails.  That's what @DumbCoder was referring to in his comment on your original question." The next day the market opens trading at 10.50, You haven't specified whether you limit order for $10.10 is to buy or sell. When the trading opens next day, it follows the same process of matching the orders. So if you have put a limit order to buy at $10.10 and there is no sell order at that price, your trade will not go through. If you have placed a limit sell order at $10.10 and there is a buyer at or higher price, it would go through. The Open price is the price of the first trade of the day. Stop order is triggered when the market reaches the price you set. Until then - its not on the books. Your understanding is wrong in that you don't go to read the definition of the term. Typically this isn't a random order- having a small volume just means it's not showing on the chart, but it is a vlid price point. Same thing would've happened if it would've been a very large order that shows on the chart. Consider also that this could have been the first one of many transactions that go far below your stop point - would you not have wanted it to be executed then, at this time, as it did? Would you expect the system to look into future and decide that this is a one time dip, and not sell; versus it is a crash, and sell? Either way, the system cannot look in the future, so it has no way to know if a crash is coming, or if it was a short dip; therefore the instrcutions are executed as given - sell if any transfer happens below the limit. To avoid that (or at least reduce the chance for it), you can either leave more distance (and risk a higher loss when it crashes), or trade higher volumes, so the short small dip won't execute your order; also, very liquid stocks will not show such small transaction dips. "If there are no limit orders on the opposite side of the book when your market order gets its turn for execution, it should be rejected by the market.  A market order should generally not ""sit on the book"" like your question suggests waiting for another order to arrive.  Thus, the situation that you describe should not happen in an ordinary market that is operating in an orderly fashion. This is not to say that your order cannot ""sit"" for a while in a queue - If there is heavy volume, orders will be executed in order, so your your market order may have to wait for orders entered ahead of it to be processed.  But once its turn comes up, that's it. There are some related points to consider: I should caution that my answer is biased a bit to US stock markets, whereas you asked about currency markets.  I believe the same basic principles apply, but I'd be swayed by someone with evidence to the contrary.  I'd also note that currency tends to be more liquid than stock, so I think it's less likely that this situation would come up.  Maybe possible for a ""weak"" currency or a currency that experiences a sudden crisis of some sort." "Yes. There are several downsides to this strategy: You aren't taking into account commissions. If you pay $5 each time you buy or sell a stock, you may greatly reduce or even eliminate any possible gains you would make from trading such small amounts. This next point sounds obvious, but remember that you pay a commission on every trade regardless of profit, so every trade you make that you make at a loss also costs you commissions. Even if you make trades that are profitable more often than not, if you make quite a few trades with small amounts like this, your commissions may eat away all of your profits. Commissions represent a fixed cost, so their effect on your gains decreases proportionally with the amount of money you place at risk in each trade. Since you're in the US, you're required to follow the SEC rules on pattern day trading. From that link, ""FINRA rules define a “pattern day trader” as any customer who executes four or more “day trades” within five business days, provided that the number of day trades represents more than six percent of the customer’s total trades in the margin account for that same five business day period."" If you trip this rule, you'll be required to maintain $25,000 in a margin brokerage account. If you can't maintain the balance, your account will be locked. Don't forget about capital gains taxes. Since you're holding these securities for less than a year, your gains will be taxed at your ordinary income tax rates. You can deduct your capital losses too (assuming you don't repurchase the same security within 30 days, because in that case, the wash sale rule prevents you from deducting the loss), but it's important to think about gains and losses in real terms, not nominal terms. The story is different if you make these trades in a tax-sheltered account like an IRA, but the other problems still apply. You're implicitly assuming that the stock's prices are skewed in the positive direction. Remember that you have limit orders placed at the upper and lower bounds of the range, so if the stock price decreases before it increases, your limit order at the lower bound will be triggered and you'll trade at a loss. If you're hoping to make a profit through buying low and selling high, you want a stock that hits its upper bound before hitting the lower bound the majority of the time. Unless you have data analysis (not just your intuition or a pattern you've talked yourself into from looking at a chart) to back this up, you're essentially gambling that more often than not, the stock price will increase before it decreases. It's dangerous to use any strategy that you haven't backtested extensively. Find several months or years of historical data, either intra-day or daily data, depending on the time frame you're using to trade, and simulate your strategy exactly. This helps you determine the potential profitability of your strategy, and it also forces you to decide on a plan for precisely when you want to invest. Do you invest as soon as the stock trades in a range (which algorithms can determine far better than intuition)? It also helps you figure out how to manage your risk and how much loss you're willing to accept. For risk management, using limit orders is a start, but see my point above about positively skewed prices. Limit orders aren't enough. In general, if an active investment strategy seems like a ""no-brainer"" or too good to be true, it's probably not viable. In general, as a retail investor, it's foolish to assume that no one else has thought of your simple active strategy to make easy money. I can promise you that someone has thought of it. Trading firms have quantitative researchers that are paid to think of and implement trading strategies all the time.  If it's viable at any scale, they'll probably already have utilized it and arbitraged away the potential for small traders to make significant gains. Trust me, you're not the first person who thought of using limit orders to make ""easy money"" off volatile stocks. The fact that you're asking here and doing research before implementing this strategy, however, means that you're on the right track. It's always wise to research a strategy extensively before deploying it in the wild. To answer the question in your title, since it could be interpreted a little differently than the body of the question: No, there's nothing wrong with investing in volatile stocks, indexes, etc. I certainly do, and I'm sure many others on this site do as well. It's not the investing that gets you into trouble and costs you a lot of money; it's the rapid buying and selling and attempting to time the market that proves costly, which is what you're doing when you implicitly bet that the distribution of the stock's prices is positively skewed. To address the commission fee problem, assuming a fee of $8 per trade ... and a minimum of $100 profit per sale Commissions aren't your only problem, and counting on $100 profit per sale is a significant assumption. Look at point #4 above. Through your use of limit orders, you're making the implicit assumption that, more often than not, the price will trigger your upper limit order before your lower limit order. Here's a simple example; let's assume you have limit orders placed at +2 and -2 of your purchase price, and that triggering the limit order at +2 earns you $100 profit, while triggering the limit order at -2 incurs a loss of $100. Assume your commission is $5 on each trade.  If your upper limit order is triggered, you earn a profit of 100 - 10 = 90, then set up the same set of limit orders again. If your lower limit order is triggered this time, you incur a loss of 100 + 10 = 110, so your net gain is 90 - 110 = -20. This is a perfect example of why, when taking into account transaction costs, even strategies that at first glance seem profitable mathematically can actually fail.  If you set up the same situation again and incur a loss again (100 + 10 = 110), you're now down -20 - 110 = -130. To make a profit, you need to make two profitable trades, without incurring further losses.  This is why point #4 is so important. Whenever you trade, it's critical to completely understand the risk you're taking and the bet you're actually making, not just the bet you think you're making. Also, according to my ""algorithm"" a sale only takes place once the stock rises by 1 or 2 points; otherwise the stock is held until it does. Does this mean you've removed the lower limit order? If yes, then you expose yourself to downside risk. What if the stock has traded within a range, then suddenly starts declining because of bad earnings reports or systemic risks (to name a few)? If you haven't removed the lower limit order, then point #4 still stands.  However, I never specified that the trades have to be done within the same day.  Let the investor open up 5 brokerage accounts at 5 different firms (for safeguarding against being labeled a ""Pattern Day Trader""). Each account may only hold 1 security at any time, for the span of 1 business week. How do you control how long the security is held? You're using limit orders, which will be triggered when the stock price hits a certain level, regardless of when that happens. Maybe that will happen within a week, or maybe it will happen within the same day. Once again, the bet you're actually making is different from the bet you think you're making. Can you provide some algorithms or methods that do work for generating some extra cash on the side, aside from purchasing S&P 500 type index funds and waiting? When I purchase index funds, it's not to generate extra liquid cash on the side. I don't invest nearly enough to be able to purchase an index fund and earn substantial dividends. I don't want to get into any specific strategies because I'm not in the business of making investment recommendations, and I don't want to start. Furthermore, I don't think explicit investment recommendations are welcome here (unless it's describing why something is a bad idea), and I agree with that policy. I will make a couple of points, however. Understand your goals. Are you investing for retirement or a shorter horizon, e.g. some side income? You seem to know this already, but I include it for future readers.  If a strategy seems too good to be true, it probably is. Educate yourself before designing a strategy. Research fundamental analysis, different types of orders (e.g., so you fully understand that you don't have control over when limit orders are executed), different sectors of the market if that's where your interests lie, etc. Personally, I find some sectors fascinating, so researching them thoroughly allows me to make informed investment decisions as well as learn about something that interests me. Understand your limits. How much money are you willing to risk and possibly lose? Do you have a risk management strategy in place to prevent unexpected losses? What are the costs of the risk management itself? Backtest, backtest, backtest. Ideally your backtesting and simulating should be identical to actual market conditions and incorporate all transaction costs and a wide range of historical data. Get other opinions. Evaluate those opinions with the same critical eye as I and others have evaluated your proposed strategy."