Why do I get a much better price for options with a limit order than the ask price?
Sounds to me like you're describing just how it should work.  Ask is at 30, Bid is at 20; you offer a new bid at 25.  Either: Depending on liquidity, one or the other may be more likely. This Investorplace article on the subject describes what you're seeing, and recommends the strategy you're describing precisely. Instead of a market order, take advantage of the fact that the options world truly is a marketplace — one where you can possibly get a better price just by asking. How does that work? If you use a limit order (instead of a market order) when opening a position, you can tell your broker how much you are willing to pay to enter a trade. For example, if you enter a limit price of $1.15, you can see whether the market-maker will bite. You will be surprised at how many times you will get your price (i.e., $1.15) instead of the ask price of $1.30. If your order at $1.15 is not filled after a few minutes, you can modify your order and pay the ask price by entering a market order or limit order at the ask price (that is, you can tell your broker to pay no more than $1.30). There are people whose strategy revolves around putting orders at the bid and ask and making money off people who cross the spread.  If you put an order in between the current bid/ask, people running that type of strategy will usually pick it off, viewing it as a discount to the orders that they already have on the bid/ask.  Often these people are trading by computer, so your limit order may get hit so quickly that it appears instantaneous to you.  In reality, you were probably hit by a limit order placed specifically to fill against yours. There are usually so many different options around for the same stock that some are rarely traded. Especially if the price has moved since the option was issued, nobody might be interested in that particular option at that price anymore. So the asking price might be something that someone asked for ages ago and that is much higher than anyone would reasonably pay today.  With a bid of $20 and an ask of $30, nobody is trading, but the value of that option is somewhere between $20 and $30. If the value is below $25, someone will notice your $25 bid and sell. I can often get the option at [a] price [between bid and ask] The keyword you use here is quite relevant: often. More realistically, it's going to be sometimes. And that's just how supply and demand should work.  The ask is where you know you can buy right away. If you don't wanna buy at ask, you can try and put a higer bid but you can only hope someone will take it before the price moves. If prices are moving up fast, you will have missed a chance if you gambled mid-spread. Having said that, the larger the spread is, the more you should work with limits mid-spread. You don't want to just take ask or bid with illiquid options. Make a calculation of the true value of the option (i.e. using the Black Scholes Model), then set your bid around there. Of course, if not only the option but also the underlying is illiquid, this all gets even more difficult. 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.
You put in a market order when you want to sell to whomever raises their hand first.  It results in the fastest possible liquidation of your stock. It's appropriate when you need to sell now, regardless of price. An example of when to use it: It's 3:55 PM, the market's going to close in 5 minutes and you need to sell some stocks to make some kind of urgent payment elsewhere.  If instead you have a limit order in place, you might not reach the limit price before the market closes, and you'll still own the stock, which might not be what you want. "If the strike price closest to the underlying has high open interest, the options expiration is a bigger event.   For instance:  stock is at $20 w/ average volume of 100,000 shares per day.    20 strike has 1000 open interest.   In this example the stock will ""most likely"" pin at 20 if we were expiring tomorrow.     As u prob know, long calls at 19.90 close, turn into stock....long puts at 20.10 turn into short stock.   Option pros (high % of volume) dont want to be short or long after expiration.   Long call holders will sell above 20 to hedge, and long put holders will buy below 20.   1000 open interest is equivalent to 100,000 shares.   That's the same amount as the average volume.   Stock can't really move until after expiration.   If I am long 10 $20 calls, and short 1000 shares I am flat going into expiration.....unless the stock gets smoked and now I am synthetically long a put....Short stock + long call= Long Put Then watch out cause it was artificially locked down." Stock price is determined by what's being asked for it, and what's being paid for it. The reported price is either a recent average, or is the last price at which a sale actually took place, depending on which you've asked for. Limit orders are an agreement between you and your brokerage, and have no direct effect on price. When and if their condition is triggered and the transaction takes place, the transaction is what's significant. On July 20, when you posted this question, AAPL was trading almost at 115.  The market charges an extra premium for buying an option that is in the money (or on the money like this case) over one that is out of the money.  In order for the 130 Call to be worth something the market has to go up 15 points. Otherwise you lose 100% of your premium. On the other hand with the 115 every point that the market goes up means that you recover some of that premium. It is much more likely that you recover part of your premium with the 115 than with the 130.  With the higher probability of losing part of the premium, the sellers are going to be reluctant to write the option unless they receive larger compensation. 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. 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. A few of the answers are spot on but here's another thing to consider: the type of trade. For example, I sometimes day trade stocks with momentum where the stock price is spiking relatively fast. A limit order in this situation may never get filled and you will miss out on the trade. A market order will get you filled but you mostly likely pay more than your limit order. However you are now catching the wave up.  Overall, using a limit or market is relative to your trading style and the type of trade. I always prefer to use a limit buy order. It definitely depends on the exchange you are trading on. I'm not familiar with Scottrade, but a standard practice is to fulfill limit orders in the order they are placed.   Most of the time, you wouldn't see stocks trade significantly under your bid price, but since penny stocks are very volatile, it's more likely their price could drop quickly past your bid and then return above it while only fulfilling a portion of the orders placed. Example 1. Penny stock priced at $0.12 2. Others place limit orders to buy at $0.10 3. You place limit order to buy at $0.10 4. Stock price drops to $0.07 and some orders are filled (anything $0.07 or higher) based on a first-come first-served basis 5. Due to the increase in purchases of the penny stock, the price rises above $0.10 before your order is filled ***EDIT*** - Adding additional clarification from comment section. A second example If the price drops from $0.12 to $0.07, then orders for all prices from $0.07 and above will start to be filled from the oldest order first. That might mean that the oldest order was a limit buy order for 100 shares at $0.09, and since that is above the current ask price, it will be filled first. The next order might be for 800 shares at $0.07. It's possible for a subset of these to be filled (let's say 400) before the share's price increases from the increased demand. Then, if the price goes above $0.10, your bid will not be filled during that time. Looking at the SPY option chain you posted, all of the call options with a strike price of 199.50 or higher have a bid of N/A.  That's because the ask price for all of those options is 0.01, and the bid price has to be less than the ask price, but buyers are not allowed to bid 0.00.  It's not accurate to say that no one wants to buy those calls - anyone who wanted to buy one of those calls would just buy it at the ask price of 0.01. So why are people selling those calls for just 0.01?  The further out of the money you go as you get closer to expiration, the less likely the underlying stock or ETF (SPY in this case) will go over the strike price, and the less you can sell it for.  SPY closed yesterday at about 195, and it would have to go up almost 2.5% today for the 199.50 calls to be in the money, and a 2.5% move in one day is extremely unlikely. 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. When you buy a call option, you transfer the risk to the owner of the asset. They are risking losing out on gains that may accumulate in addition to the strike price and paid premium. For example, if you buy a $25 call option on stock XYZ for $1 per contract, then any additional gain above $26 per share of XYZ is missed out on by the owner of the stock and solely benefits the option holder. By buying the call option, you are getting the benefit of purchasing the underlying shares (that is, if the shares go up in value, you make money), but transferring the risk of the shares reducing in value. This is more apparent when you are using the option to offset an explicit risk that you hold. For example, if you have a short position, you are at unlimited risk of the position going up in value. You could decide you only want to take the risk that it might rise to $X. In that case, you could buy a call option with $X strike price. Then you have transferred the risk that the position goes over $X to the counterpart, since, even if the shares are trading at $X+$Y you can close out the short position by purchasing the shares at $X, while the option counterpart will lose $Y. 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 assume you're talking about a sell order, not a buy order. When you place a limit sell order, your order is guaranteed to be placed at that price or higher.  If the market is currently trading much higher than the price of your sell order, then your mistakenly low limit order will be essentially a market order, and will be filled at  the current bid price. So the only way this is a problem is if you want to place a limit sell that is much higher than the current market, but mistakenly place a limit lower than the current market. The UK has historically aggressive financial law, inherited from Dutch friendship, influence, and acquisitions by conquest. The law is so open that nearly anyone can invest through the UK without much difficulty, and citizens have nearly no restrictions on where to invest. A UK citizen can either open an account in the US with paperwork hassles or at home with access to all world markets and less paperwork.  Here is the UK version of my broker, Interactive Brokers.  Their costs are the lowest, but you will be charged a minimum fee if you do not trade enough, and their minimum opening balance can be prohibitively high for some. If you do buy US products, be sure to file your W-8BEN.