Price/Time priority order matching - limit order starvation
"Market orders do not get priority over limit orders.  Time is the only factor that matters in price/time order matching when the order price is the same. For example, suppose the current best available offer for AAPL is $100.01 and the best available bid is $100.00.  Now a limit buy for $100.01 and a market buy arrive at around the same instant.  The matching engine can only receive one order at a time, no matter how close together they arrive. Let's say that by chance the limit buy arrives first.  The engine will check if there's a matching sell at $100.01 and indeed there is and a trade occurs.  This all happens in an instant before the matching engine ever sees the market buy.  Then it moves on to the market buy and processes it accordingly. On the other hand, let's say that by chance the market buy arrives first.  The engine will match it with the best available sell (at $100.01) and a trade occurs.  This all happens in an instant before the matching engine ever sees the limit buy.  Then it moves on to the limit buy and processes it accordingly. So there's never a comparison between the two orders or their ""priorities"" because they never exist in the system at the same time.  The first one to arrive is processed first; the second one to arrive is processed second."
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. Difference between a limit and market order is largely a trade-off between price certainty and timing certainty. If you think the security is already well priced, the downside of a limit order is the price may never hit your limit and keep trading away from you. You'll either spend a lot of time amending your order or sitting around wishing you'd amended your order.  The downside of a market order is you don't know the execution price ahead of time. This is typically more of a issue with illiquid instruments where even smaller orders may have price impact. For small trades in more liquid securities your realized price will often resemble the last traded price. Hope that helps. Both have a purpose, and the best tool for the job will depend on your circumstances. As others have stated, the current price is simply the last price at which the security traded. For any given tick, however, there are many bid-ask prices because securities can trade on multiple exchanges and between many agents on a single exchange. This is true for both types of exchanges that Chris mentioned in his answer. Chris' answer is pretty thorough in explaining how the two types of exchanges work, so I'll just add some minor details. In exchanges like NASDAQ, there are multiple market makers for most relatively liquid securities, which theoretically introduces competition between them and therefore lowers the bid-ask spreads that traders face. Although this results in the market makers earning less compensation for their risk, they hope to make up the difference by making the market for highly liquid securities. This could also result in your order filling, in pieces, at several different prices if your brokerage firm fills it through multiple market makers. Of course, if you place your order on an exchange where an electronic system fills it (the other type of exchange that Chris mentioned), this could happen anyway.  In short, if you place a market order for 1000 shares, it could be filled at several different prices, depending on volume, multiple bid-ask prices, etc. If you place a sizable order, your broker may fill it in pieces regardless to prevent you from moving the market. This is rarely a problem for small-time investors trading securities with high volumes, but for investors with higher capital like institutional investors, mutual funds, etc. who place large orders relative to the average volume, this could conceivably be a burden, both in the price difference across time as the order is placed and the increased bookkeeping it demands.  This is tangentially related, so I'll add it anyway. In cases like the one described above, all-or-none (AON) orders are one solution; these are orders that instruct the broker to only execute the order if it can be filled in a single transaction. Most brokers offer these, but there are some caveats that apply to them specifically. (I haven't been able to find some of this information, so some of this is from memory).  All-or-none orders are only an option if the order is for more than a certain numbers of shares. I think the minimum size is 300 or 400 shares.  Your order won't be placed until your broker places all other orders ahead of it that don't have special conditions attached to them.  I believe all-or-none orders are day orders, which means that if there wasn't enough supply to fill the order during the day, the order is cancelled at market close.  AON orders only apply to limit orders. If you want to replicate the behavior of a market order with AON characteristics, you can try setting a limit buy/sell order a few cents above/below the current market price. 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. In practice, it would not work. If you put a bid in that was really out of line, even if it got filled, the exchange would reverse it.  Other than that it really depends on what the current bid/ask spread it, and what volume its trading, as well as how the market feels. Say the current bid is 11 and you put an order in with bid 11.5, it would soak up all the orders on the market up to the volume your buying. But once your order is filled the market will be determined by what the next order's bid/ask is. It might stay where you moved it too if others feels thats a fair price. But if every other order on the market is still at 11, then the price isnt gonna move.  tl;dl unless your a market maker, you could not realistically affect the price. I frequently do this on NADEX, selling out-of-the-money binary  calls. NADEX is highly illiquid, and the bid/ask is almost always from  the market maker. Out-of-the-money binary calls lose value quickly  (NADEX daily options exist for only ~21 hours). If I place an  above-ask order, it either gets filled quickly (within a few minutes)  due to a spike in the underlying, or not at all. I compensate by  changing my price hourly.  As Joe notes, one of Black-Scholes inputs is volatility, but price  determines (implied) volatility, so this is circular. In other words, you can  treat the bid/ask prices as bid/ask volatilities. This isn't as  far-fetched as it seems:  http://www.cmegroup.com/trading/fx/volatility-quoting-fx-options.html Personally, I have entry and exit signal generating functions, which also have sizing, stop and target functions...  E.g. based on some entry you have an optimal bet, take profit and stop loss.  Algorithmic execution is generally used for large orders to prevent walking the book. 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.