When are stop market/limit orders visible on the open market?
From the non-authoritative Investopedia page: A stop-limit order will be executed at a specified price, or better, after a given stop price has been reached. Once the stop price is reached, the stop-limit order becomes a limit order to buy or sell at the limit price or better. So once the stop price has been breached, your limit order is placed and will be on the order books as a $9 ask. For a vanilla stop order, a market order will be placed and will be filled using the highest active bid(s).
If you want your order to go through no matter what then you should be using market orders rather than limit orders. With limit orders you may get the price you are after or better but you are not guaranteed to get your order transacted. With a market order you are guaranteed to get you order transacted but may get a price inferior to what you were after. Most times this should only be a few cents but can get much larger in a fast moving or less liquid market. You should incorporate this slippage into your trading plan. Maybe a better option for you, if you are looking at + or - 0.5% from the last price, would be to use conditional triggers (stop buy and sell orders) with your market orders. Once the market moves in your direction your conditional order will be triggered and the stock will be bought at current market price. I don't think you're missing anything. Many modern trading systems actually warn you when trying to enter a market order, asking if you are sure that you wouldn't prefer to set a limit. I fully agree with you that it is usually just better to define a limit even 20% higher than just doing a market trade. Let me give you some examples when you still might prefer to use a market order instead of a limit: But even in those two examples a (wide) limit order might just be the safer thing to do.  So, what it really comes down to is speed: A market order has no other criterias to be defined, is thus entered faster and saves you a few seconds that might be crucial. "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." From your question, I am guessing that you are intending to have stoploss buy order. is the stoploss order is also a buy order ?  As you also said, you seems to limit your losses, I am again guessing that you have short position of the stock, to which you are intending to place a buy limit order and buy stoploss order (stoploss helps when when the price tanks). And also I sense that you intend to place buy limit order at the price below the market price. is that the situation?  If you place two independent orders (one limit buy and one stoploss buy). Please remember that there will be situation where two orders also get executed due to market movements. Add more details to the questions. it helps to understand the situation and others can provide a strategic solution. It will depend largely on your broker what type of stop and trailing stop orders they provide. Saying that, I have not come across any brokers yet that offer limit orders with trailing stop orders.  Unlike a standard stop order where you can either make it a market stop order or a limit stop order, usually most brokers have trailing stop orders as market orders only, where you can either set the trailing stop to be a dollar value or percentage from the most recent high. Remember also, that trailing stop orders will be based on the intra-day highs and not the highest closing price. That means that if the share price spikes up during the day your trailing stop will move up, and if the price then spikes down you may be stopped out prematurely, after which the price might rally again. For this reason I try to base my trailing stops on the highest closing price by using standard stop loss orders and moving it up manually after the close of trade if the share price has closed at a new high. This takes a few minutes each evening (depending on how many stocks you have to check and adjust the stops for) but gives you more control. Using this method will also enable you to set limit orders attached to your stop loss triggers, and you won't have to keep your trailing too close to the last high price thus potentially causing you to get stopped out prematurely. Slightly off track but may be handy if you set profit targets, my broker has recently introduced Trailing Take Profit Orders. The way it works is, say you have a profit target of 50%, so you buy at $2 and want to take profits if the price reaches $3, you could set your Trailing Take Profit Trigger at say $3.10 or above and set a Trail by Amount of say $0.10. So if the price after hitting $3.10 falls to $3.00 you will be stopped out and collect your profits. If the price moves up to $3.30 and then falls to $3.20, you will be stopped out at $3.20 and make some extra profits. If the price continues going up the Trailing Take Profit will continue to move up always $0.10 below the highest price reached. I think this would be a very useful order if you were range trading where you could set the Trailing Take Profit trigger near recent resistance so you can get out if prices start reversing at or around the resistance, but continue profiting if the price breaks through the resistance. "For any large company, there's a lot of activity, and if you sell at ""market"" your buy or sell will execute in seconds within a penny or two of the real-time ""market"" price.  I often sell at ""limit"" a few cents above market, and those sell within 20 minutes usually.  For much smaller companies, obviously you are beholden to a buyer also wanting that stock, but those are not on major exchanges.  You never see whose buy order you're selling into, that all happens behind the curtain so to speak." "Yes there is, it is called a One-Cancels-the-Other Order (OCO). Investopedia defines a OCO order as: Definition of 'One-Cancels-the-Other Order - OCO' A pair of orders stipulating that if one order is executed, then the   other order is automatically canceled. A one-cancels-the-other order   (OCO) combines a stop order with a limit order on an automated trading   platform. When either the stop or limit level is reached and the order   executed, the other order will be automatically canceled. Seasoned   traders use OCO orders to mitigate risk. I use CMC Markets in Australia, and they allow free conditional and OCO orders either when initially placing a buy order or after already buying a stock. See the Place New Order box below:  Once you have selected a stock to buy, the number of shares you want to buy and at what price you can place up to 3 conditional orders. The first condition is a ""Place order if..."" conditional order. Here you can place a condition that your buy order will only be placed onto the market if that condition is met first.  Say the stock last traded at $9.80 and you only want to place your order the next day if the stock price moves above the current resistance at $10.00. So you would Place order if Price is at or above $10.00. So if the next day the price moves up to $10 or above your order will be placed onto the market. The next two conditional orders form part of the OCO Orders. The second condition is a ""Stop loss"" conditional order. Here you place the price you want to sell at if the price drops to or past your stop loss price. It will only be placed on to the market if your buy order gets traded. So if you wanted to place your stop loss at $9.00, you would type in 9.00 in the box after ""If at or below ?"" and select if you want a limit or market order. The third condition is a ""Take profit"" conditional order. This allows you to take profits if the stock reaches a certain price. Say you wanted to take profits at 30%, that is if the price reached $13.00. So you would type in 13.00 in the box after ""If at or above ?"" and again select if you want a limit or market order. Once you have bought the stock if the stop order gets triggered then the take profit order gets cancelled automatically. If on the other hand the take profit order gets triggered then the stop loss order gets cancelled automatically. These OCO conditional orders can be placed either at the time you enter your buy order or after you have already bought the stock, and they can be edited or deleted at any time. The broker you use may have a different process for entering conditional and OCO orders such as these." 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). Many of the Bitcoin exchanges mimic stock exchanges, though they're much more rudimentary offering only simple buy/sell/cancel orders.  It's fairly normal for retail stock brokerage accounts to allow other sorts of more complex orders, where once a certain criteria is met, (the price falls below some $ threshold, or has a movement greater than some %) then your order is executed.  The space between the current buy order and the current sell order is the bid/ask spread, it's not really about timing.  Person X will buy at $100, person Y will sell at $102.  If both had a price set at $101, they would just transact.  Both parties think they can do a little bit better than the current offer.  The width of the bid/ask spread is not universal by any means.  The current highest buy order and the current lowest sell order, are both the current price.  The current quoted market price is generally the price of the last transaction, whether it's buy or sell. My broker collates the order book by price and marketplace, displaying the number of shares available at each level, sorted as in Victor's screencap. You can glean information from not just a snapshot of the order book but also by watching how it changes over time. Although it's not always a complete picture -- many brokers hold limit orders internally until the market is close, at which point they'll route to an exchange or trade internally. And of course skilled market participants know that there's people out there looking to glean information from the order book and will act to confuse the picture. The order book can show you: Combined with a list of trades (price & size, and whether it was a buy or sell), you can get a much more complete picture of what's going on with a stock than by looking at charts alone. "My broker offers the following types of sell orders: I have a strategy to sell-half of my position once the accrued value has doubled.  I take into account market price, dividends, and taxes (Both LTgain and taxes on dividends).  Once the market price exceeds the magic trigger price by 10%, I enter a ""trailing stop %"" order at 10%.  Ideally what happens is that the stock keeps going up, and the trailing stop % keeps following it, and that goes on long enough that accrued dividends end up paying for the stock.  What happens in reality is that the stock goes up some, goes down some, then the order gets cancelled because the company announces dividends or something dumb like that. THEN I get into trouble trying to figure out how to re-enter the order, maintaining the unrealized gain in the history of the trailing stop order.  I screwed up and entered the wrong type of order once and sold stock I didn't want to. Lets look at an example. a number of years ago, I bought some JNJ -- a hundred shares at 62.18.  - Accumulated dividends are 2127.75  - My spreadsheet tells me the ""double price"" is 104.54, and double + 10% is 116.16.  - So a while ago, JNJ exceeded 118.23, and I entered a Trailing Stop 10% order to sell 50 shares of JNJ.  The activation price was 106.41.  - since then, the price has gone up and down...  it reached a high of 126.07, setting the activation price at 113.45.  - Then, JNJ announced a dividend, and my broker cancelled the trailing stop order.  I've re-entered a ""Stop market"" order at 113.45.  I've also entered an alert for $126.07 -- if the alert gets triggered, I'll cancel the Market Stop and enter a new trailing stop." "During the day, market and limit orders are submitted at any time by market participants and there is a bid and an ask that move around over time.  Trades occur whenever a market order is submitted or a limit order is submitted that at a price that matches or exceeds an existing limit order.  If you submit a market order, it may consume all best-price limit orders and you can get multiple prices, changing the bid or ask at the same time.  All that stuff happens during the trading day only. What happens at the end of the day is different.  A bunch of orders that were submitted during the day but marked as ""on close"" are aggregated with any outstanding limit orders to create a single closing price according to the algorithm established by the exchange.  Each exchange may handle the details of this closing event differently.  For example, the Nasdaq's closing cross or the NYSE's closing auction. The close is the most liquid time of the day, so investors who are trading large amounts and not interested in intraday swings will often submit a market-on-close or limit-on-close order.  This minimizes their chance of affecting the price or crossing a big spread.  It's actually most relevant for smaller stocks, which may have too little volume during the day to make big trades, but have plenty at the close.  In short, the volume you see is due to these on-close orders. The spike in volume most likely has no special information about what will happen overnight or the next day.  It's probably just a normal part of the market for illiquid stocks." Because in the case for 100/101, if you wanted to placed a limit buy order at top of the bid list you would place it at 101 and get filled straight away. If placing a limit buy order at the top of 91 (for 90/98) you would not get filled but just be placed at the top of the list. You might get filled at a lower price if an ask comes in matching your bid, however you might never get filled. In regards to market orders, with the 100/101 being more liquid, if your market order is larger than the orders at 101, then the remainder of your order should still get filled at only a slightly higher price. In regards to market orders with the 90/98, being less liquid, it is likely that only part of your order gets filled, and any remained either doesn't get filled or gets filled at a much higher price. Probing for hidden limit orders usually involves sending the orders and then cancelling them before they get filled if they don't get filled. With trades actually going through multiple times for small amounts it looks more like a VWAP strategy where the trader is feeding small volumes into the market as part of a larger trade trying to minimize average cost. It could be probing but without seeing the orders and any cancels it would be difficult to tell. edit: I just had another thought; it could possibly be a market maker unwinding a bad position caused by other trading. Sometimes they drip trades into the market to prevent themselves from hitting big orders etc. that might move back against them. This is probably not right but is just another thought. source: I work for an organization that provides monitoring for these things to many large trading organizations. What you have to remember is that Options are derivatives of another asset like stocks for example.  The price of the Option is derived from the price of the underlying. If the underlying is a stock for example, as the price of the stock moves up and down during the trading day, so will the Market Maker's fair value for the Option.  As Options are usually less liquid than the underlying stock, Market Makers are usually more active in 'Providing a Market' with Options. Thus if you place a limit order half way between the current Bid and Ask and the underlying stock price moves towards your limit order, the Market Maker will do their job and 'Provide a Market' at that price, thus executing your order.