Are market orders safe?
"A market sell order will be filled at the highest current ""bid"" price. For a reasonably liquid stock, there will be several buy orders in line, and the highest bid must be filled first, so there should a very short time between when you place the order and when it is filled.   What could happen is what's called front running. That's when the broker places their own order in front of yours to fulfill the current bid, selling their own stock at the slightly higher price, causing your sale to be filled at a lower price.  This is not only unethical but illegal as well. It is not something you should be concerned about with a large broker.   You should only place a market order when you don't care about minute differences between the current ask and your execution price, but want to guarantee order execution. If you absolutely have to sell at a minimum price, then a limit order is more appropriate, but you run the risk that your limit will not be reached and your order will not be filled. So the risk is a tradeoff between a guaranteed price and a guaranteed execution." Market orders can be reasonably safe when dealing with stocks that are rather liquid and have quite low volatility. But it's important to note that you're trading a large degree of control over your buy / sell price for a small benefit in speed or complexity of entering an order. I always use limit orders as they help me guard against unexpected moves of the stock. Patience and attention to details are good qualities to have as an investor.
If you want to make sure you pay at or below a specific price per share, use a limit order. If you want to buy the stock close to the current price, but aren't price sensitive, use a market order. Market orders are typically not a great idea because if you're buying thousands or tens of thousands of shares this can mean a large swing in cost if the market suddenly changes direction. I have done this, and the reason is to make sure that I don't run out of money in my account to place the order if there is an unexpected upswing in price. Suppose I have $1000 in my account and I want to buy 10 shares of ABCD that are currently at $99.  If the price doesn't change, then I am all set, but if the price goes up to $101 then I don't have sufficient funds to make the purchase. By placing a limit order at $100 I can ensure that I have enough money to place the order. In general, it is a rather unlikely scenario that it could happen, but placing the limit order is easy to do and it gives me peace of mind. I don't know what you mean about bypassing the queue. "First of all, not all brokers allow trading during pre-market and post-market.  Some brokers only allow trading during the regular hours (9:30am - 4pm ET). Second of all, while you can place orders using limit orders and market orders during regular trading hours, you can only use limit orders during pre-market and post-market.  This is because the liquidity is much lower during pre-market and post-market, and using market orders could result in some trades filling at horrible prices.  So brokers don't allow using market orders outside of regular trading hours. Third, some brokers require you to specify that you want your order to be executed during pre-market or post-market.  For example, my broker allows me to specify either ""Day"" or ""Ext"" for my orders.  ""Day"" means I want my order to execute only during regular trading hours, and ""Ext"" means I want my order to execute at any time - pre-market, regular trading hours, or post-market. Finally, if your broker allows pre/post market trading, and you place a limit order while specifying ""Ext"", then your trade can happen in real-time during pre-market or post-market.  Per your example, if a stock is trading at $5 at 8am, and you put in a limit order (while specifying ""Ext"") to buy it at $5 at 8am, then your order will execute at that time and you will buy that stock at 8am." You have no guarantees. The stock may last have traded at $100 (so, the market price is $100), but is currently in free-fall and nobody else will be willing to buy it for any more than $80. Or heck, maybe nobody will be willing to buy it at all, at any price. Or maybe trading on this stock will be halted. Remember, the market price is just what the stock last traded at. If you put in a 'market order', you are ordering your broker to sell at the best available current price. Assuming someone's willing to buy your stock, that means you'll sell it. But if it last traded at $100, this doesn't guarantee you'll sell at anything close to that. I think that if the price does not go very far up, then your order will open on 101, because you are setting a limit order, if suddenly the price goes up very quickly or with a gep even, then you may not be given a position. But this is with a limit order and it is better to check with the broker. There are also warrants in which you can adjust the price range, for example, from 101 to 103, and at a sharp price jump, it is possible for you and would not give a position at a price of 101, but perhaps 103 would get. "What you are saying is a very valid concern.  After the flash crash many institutions in the US replaced ""true market orders"" (where tag 40=1 and has no price) with deep in the money limit orders under the hood, after the CFTC-SEC joint advisory commission raised concerns about the use of market orders in the case of large HFT traders, and concerns on the lack of liquidity that caused market orders that found no limit orders to execute on the other side of the trade, driving the prices of blue chip stocks into the pennies.  We also applaud the CFTC requesting comment regarding whether it is   appropriate to restrict large order execution design that results in   disruptive trading. In particular, we believe there are questions   whether it is ever appropriate to permit large order algorithms that   employ unlimited use of market orders or that permit executions at   prices which are a dramatic percentage below the present market price   without a pause for human review So although you still see a market order on the front end, it is transformed to a very aggressive limit in the back end. However, doing this change manually, by selling at price 0 or buying at 9999 may backfire since it may trigger fat finger checks and prevent your order from reaching the market.  For example BATS Exchange  rejects orders that are priced too aggressively and don't comply with the range of valid prices.  If you want your trade to execute right now and you are willing to take slippage in order to get fast execution, sending a market order is still the best alternative." Fair value can mean many different things depending on the context. And it has nothing to do with the price at which your market order would be executed. For example if you buy market, you could get executed below 101 if there are hidden orders, at 101 if that sell order is large enough and it is still there when your order reaches the market, or at a higher price otherwise. "You might consider learning how the ""matching"" or ""pairing"" system in the market operates.  The actual exchange only happens when both a buyer and a seller overlap their respect quotes.   Sometimes orders ""go to market"" for a particular volume.  Eg get me 10,000 Microsoft shares now.  which means that the price starts at the current lowest seller, and works up the price list until the volume is met.  Like all market it trades, it has it's advantages, and it's dangers.  If you are confident Microsoft is going to bull, you want those shares now, confident you'll recoup the cost.  Where if you put in a priced order, you might get only none or some shares. Same as when you sell.  If you see the price (which is the price of the last completed ""successful"" trade.  and think ""I'm going to sell 1000 shares"". then you give the order to the market (or broker), and then the same as what happened as before.  the highest bidder gets as much as they asked for, if there's still shares left over, they go to the next bidder, and so on down the price... and the last completed ""successful"" trade is when your last sale is made at the lowest price of your batch. If you're selling, and selling 100,000 shares. And the highest bidder wants 1,000,000 shares you'll only see the price drop to that guys bid.  Why will it drop (off the quoted price?).  Because the quoted price is the LAST sale, clearly if there's someone still with an open bid on the market...then either he wants more shares than were available (the price stays same), or his bid wasn't as high as the last bid (so when you sale goes through, it will be at the price he's offering).   Which is why being able to see the price queues is important on large traders. It is also why it can be important put stops and limits on your trades, een through you can still get gapped if you're unlucky.  However putting prices (""Open Orders"" vs ""(at)Market Orders"") can mean that you're sitting there waiting for a bounce/spike while the action is all going on without you). safer but not as much gain (maybe ;) ) that's the excitement of the market, for every option there's advantages...and risks... (eg missing out) There are also issues with stock movement, shadowing, and stop hunting, which can influence the price. But the stuff in the long paragraphs is the technical reasons." Rule 610 (Google for it) stands that if Bid and Ask are the same, the market is considered Locked, and the exchange must stop all trading. So the same person can't quote the same bid and ask price. However, HFTs have found ways to circumvent this limitation when exchanges created special order types for them, e.g. Spam-and-Cancel "The risk of market orders depends heavily on the size of the market and the exchange. On big exchange and a security which is traded in hue numbers you're likely that there are enough participants to give you a ""fair"" price. Doing a market order on a security which is hardly dealed you might make a bad deal. In Germany Tradegate Exchange and the sister company the bank Tradegate AG are known to play a bit dirty: Their market is open longer than Frankfurt (Xetra) and has way lower liquidity. So it can happen that not all sell or buy orders can be processes on the Exchange and open orders are kept. Then Tradegate AG steps in with a new offer to full-fill these trades selling high or buying low. There is a German article going in details on wiwo.de either German or via Google Translate" Unless you want to be a short term day trader, then it is not foolish to be an end of day trader. If you are looking to be a medium to long term trader/investor then it is quite acceptable to put orders in after market close. Some would say it is even less risky, because you are not watching the price fluctuate up and down and letting your emotions getting the best of you. "I commend you for your desire to be a smart and engaged investor. Regarding the other comments, yes the market is unpredictable and dangerous, but such is everything that leads to profit.  I am currently reading, ""Advanced Options Pricing Models"" (Katz and McCormick) - mighy be at your local library. The book is helpful because in explaining the options market, it covers basic stock methodologies and then builds on them as it pursues a quant's math/computation based view of the market. The book is highly math oriented and discusses authors' custom design scripts/alogrithms to analyze market behavior. See similar post about technical analysis (since it often directs short term trading decisisions)." "Theres nothing wrong with CDOs or Synthetic ones. What is important is that they are labelled correctly in terms of their risk. You cant be selling risky CDOs as ""safe"" bets.   If the rating agencies and financial institutions rate them correctly then I dont see a problem with it." One broker told me that I have to simply read the ask size and the bid size, seeing what the market makers are offering. This implies that my order would have to match that price exactly, which is unfortunate because options contract spreads can be WIDE. Also, if my planned position size is larger than the best bid/best ask, then I should break up the order, which is also unfortunate because most brokers charge a lot for options orders. "I'm surprised people don't bring this up more often....if you add together, not just our sovereign debt, but public and private debt, plus our contingent liabilities, meaning FHA, student loans, fannie mae, freddie mac, AIG, etc.  that totals over $100 TRILLION dollars, more than we could ever pay back, meaning literally there is no amount of growth and taxes that could ever pay this money back. (cite my sources do a google search of James Rickards Hopkins lecture it's in the first few minutes)  The reason you need to add all that together is because the economy can't grow if nobody has any money for investment, etc. (there isn't much home equity left after the housing crisis, retirement plans aren't holding as much, etc.) there wouldn't be an easy way to grow this economy, that's why we have ""currency wars"" competitive devaluations....to me we're already over the cliff I don't see us heading back, but I'm not saying that means we're going to collapse, just we'll need to go back to some sort of standard where our currency is backed by something (i.e. commodities or gold or something) and there are going to be A LOT of losses in the near term....meaning I want OUT of dollars....  combined with our lazy/entitled generation (don't tell me creating some website where you can order artistic candy on a stick is going to save our economy...we need to produce and innovate again to lower our trade deficit and so people actually bring their capital here), and dwindling resources I'd say it's already game over, the pieces just need to move into place"