What do stock market index future bid/ask quotes mean?
"Well, futures don't have a ""strike"" like an option - the price represents how much you're obligated to buy/sell the index for at a specified date in the future.  You are correct that there's no cost to enter a contract (though there may be broker fees and margin payments).  Any difference between the contract price and the price of the index at settlement is what is exchanged at settlement.   It's analogous to the bid/ask on a stock - the bid price represents the price at which someone is willing to ""buy"" a futures contract (meaning enter into a long position) and the ask is how much someone is willing to ""sell"" a contract. So if you want to take a long position on S&P500 mini futures you'd have to enter in at the ""ask"" price.  If the index is above your contract price on the future expiry date you'll make a profit; if it is below the contract price you'll take a loss."
Options reflect expectations about the underlying asset, and options are commonly priced using the Black-Scholes model:  N(d1) and N(d2) are probability functions, S is the spot (current) price of the asset, K is the strike price, r is the risk free rate, and T-t represents time to maturity.  Without getting into the mathematics, it suffices to say that higher volatility or expectation of volatility increases the perceived riskiness of the asset, so call options are priced lower  and put options are priced higher. Think about it intuitively. If the stock is more likely to go downwards, then there's an increased chance that the call option expires worthless, so call options must be priced lower to accommodate the relative change in expected value of the option.  Puts are priced similarly, but they move inversely with respect to call option prices due to Put-Call parity. So if call option prices are falling, then put option prices are rising (Note, however, that call prices falling does not cause put prices to rise. The inverse relationship exists because of changes in the underlying factors and how pricing works.) So the option action signifies that the market believes the stock is headed lower (in the given time frame). That does not mean it will go lower, and option traders assume risk whenever they take a particular position. Bottom line: gotta do your own homework! Best of luck. "Futures are an agreement to buy or sell something in the future.  The futures ""price"" is the price at which you agree to make the trade.  This price does not indicate what will happen in the future so much as it indicates the cost of buying the item today and holding it until the future date.  Hence, for very liquid products such as stock index futures, the futures price is a very simple function of today's stock index value and current short-term interest rates.  If the stock exchange is closed but the futures exchange is open, then using the futures price and interest rates one can back out an implied ""fair value"" for the index, which is in essence the market's estimate of what the stock index value would be right now if the stock market were open.  Of course, as soon as the stock exchange opens, the futures price trades to within a narrow band of the actual index value, where the size of the band depends on transaction costs (bid-ask spread, commissions, etc.)." "- In a quote driven market, must every investor trade with a market        maker? In other words, two parties that are both not market makers        cannot trade between themselves directly? In a way yes, all trades go through a market maker but those trades can be orders put in place by a ""person"" IE: you, or me. - Does a quote driven market only display the ""best"" bid and ask        prices proposed by the market makers? In other words, only the        highest bid price among all the market makers is displayed, and        other lower bid prices by other market makers are not? Similarly,        only the lowest ask price over all market makers is displayed, and        other higher ask prices by other market makers are not? No, you can see other lower bid and higher ask prices. - In a order-driven market, is it meaningful to talk about ""the current stock price"", which is the price of last transaction? Well that's kind of an opinion. Information is information so it won't be bad to know it. Personally I would say the bid and ask price is more important. However in the real world these prices are changing constantly and quickly so realistically it is easier to keep track of the quote price and most likely the bid/ask spread is small and the quote will fall in between. The less liquid a security is the more important the bid/ask is. -- This goes for all market types. - For a specific asset, will there be several transactions happened at    the same time but with different prices? Today with electronic markets, trades can happen so quickly it's difficult to say. In the US stock market trades happen one at a time but there is no set time limit between each trade. So within 1 second you can have a trade be $50 or $50.04. However it will only go to $50.04 when the lower ask prices have been exhausted.   - Does an order driven market have market makers?  By definition, no. - What are some examples of quote driven and order driven financial markets, in which investors are commonly trading stocks and derivatives, especially in U.S.? Quote driven market: Bond market, Forex. Order driven market: NYSE comes from an order driven market but now would be better classified as a ""hybird market"" Conclusion: If you are asking in order to better understand today's stock markets then these old definitions of Quote market or Order market may not work. The big markets in the real world are neither. (IE: Nasdaq, NYSE...) The NYSE and Nasdaq are better classified as a ""hybird market"" as they use more then a single tactic from both market types to insure market liquidity, and transparency. Markets these days are strongly electronic, fast, and fairly liquid in most cases. Here are some resources to better understand these markets: An Introduction To Securities Markets The NYSE And Nasdaq: How They Work Understanding Order Execution" That looks very much like an S&P 500 E-Mini index future.  However, ES1 is a strange symbol.  Futures have the month of expiry encoded in their symbol as well:  http://commodities.about.com/od/understandingthebasics/ss/futurescontract_3.htm For example, the September 2011 future in this series would be ESU1. I'm not very familiar with Bloomberg so perhaps this is the front contract (i.e. the one that's closest to expiry (in the is case the September 2011 one)). Only problem is that prices don't exactly match what CME has (high of 1190 and low of 1186.25, for when this page gets out of date):  http://www.cmegroup.com/trading/equity-index/us-index/e-mini-sandp500.html  - but they are so close I suspect it must be some sort of S&P 500 index future. That looks like a Bloomberg terminal. And like @Jer said, it would appear to be the symbol for the S&P 500 E-mini index future. Although it doesn't look right all on its own, as it should have a modifier indicating the month (or quarter) of expiry. However, since it appears on a Bloomberg terminal in the image, I checked a source for Bloomberg Symbol Lists and found one of two possibilities for ES1. It is most likely the S&P 500 e-mini future: CME E-Mini Futures  E-Mini S&P 500    ES1 INDEX the only alternative was LIFFE 3 Month Euroswiss   ES1 COMDTY I think the former is far more likely, as the latter has the COMDTY commodity tag instead of INDEX as the tag in the image. Also, it isn't the ESI which pertains to Ethibel Sustainability Indices and something with the Eurozone (also Bloomberg Indices). Here we go! Excerpt straight is from a presentation presentation on charting from a business school PDF see pp.12-13, and appears to be a straight excerpt from September 2007 Bloomberg documentation. I didn't know any other way to imbed it besides taking a screen shot then uploading to imgur. Or of course, see pp.12-13 in the referenced PDF I've attached.  See I found the answer. It was the Stock Ticker that I was looking for. So, if I understand correctly the price at certain moment is the price of the latest sale and can be used to get a global picture of what certain stock is worth at that certain instant. "It means price movements in the past do not affect price movements in the future. Think of the situation of a coin, if you flip it once, and then you flip it a second time, the results are independent of each other. If the first time, you flipped a HEAD, it does not mean that the coin will remember it, and produce a TAIL the second time. This is the meaning of ""memoryless"". FYI, stock markets are clearly not memoryless. It is just an assumption for academic purposes." I stock is only worth what someone will pay for it.  If you want to sell it you will get market price which is the bid. Prices quoted are primarily the offer prices quoted by the numerous market makers on the stock exchange(s) willing to sell you the stock. There is another price which generally isn't seen on these websites, the bid prices, which are lower prices quoted by buyers and market makers willing to buy your shares from you. You wouldn't see those prices, unless you login to your trade terminal. How meaningful are they to you depends on what you want to do buy or sell. If you want to buy then yes they are relevant. But if you want to sell, then no. And remember some websites delay market information by 15 minutes, in case of Google you might have seen that the volume is delayed by 15 minutes. So you need to consider that also while trading, but mayn't be a concern unless you are trying to buy out the company. When a stock is ask for 15.2 and bid for 14.5, and the last market price was 14.5, what does it mean? It means that the seller wants to sell for a higher price than the last sale while the buyer does not want to buy for more than the last sale price. Or what if the last price is 15.2? The seller is offering to sell for the last sale price, but the buyer wants to buy for less. The CBOE site, as well as some other sites and trading platforms, will show the bid/ask and statistics for that option at each individual options exchange, in addition to statistics and the best bid/offer across all exchanges. cboe.com: Delayed Quote Help lists what the single-letter codes mean. A is for the AMEX options exchange, B is for BOX, X is for PHLX, etc. "With my current, limited knowledge (see end), I understand it the following way: Are share prices really described as ""memoryless""?  Yes.  Is there a   technical meaning of the term? What does it really mean? The meaning comes from Markov Models: Think of the behavior of the stock market over time as a Markov Chain, i.e. a probabilistic model with states and probabilistic transitions. A state is the current price of all stocks of the market, a transition is a step in time. Memoryless means that transitions that the stock market might make can be modelled by a relation from one state to another, i.e. it only depends on the current state. The model is a Markov Chain, as opposed to a more general Stochastic Process where the next state depends on more than the current state. So in a Markov Chain, all the history of one stock is ""encoded"" already in its current price (more precisely in all stock's prices).  The memorylessness of stocks is the main statement of the Efficient Market Theory (EMT). If a company's circumstances don't change, then a drop in its share price is going to be followed by a rise later.  So if the EMT holds, your statement above is not necessarily true. I personally belief the EMT is a good approximation - only large corporations (e.g. Renaissance Technologies) have enough ressources (hundreds of mathematicians, billions of $) to be able to leverage tiny non-random movements that stem from a not completely random, mostly chaotic market.  The prices can of course change when the company's circumstances change, but they aren't ""memoryless"" either. A company's future state is influenced by its past. In the EMT, a stock's future state is only influenced by its past as much as is encoded in its current price (more precisely, the complete market's current state). Whether that price was reached by a drop or a rise makes no difference.  The above is my believe, but I'm by far no finance expert. I am working professionally with probabilistic models, but have only read one book on finance: Kommer's ""Souverän investieren mit Indexfonds und ETFs"". It's supposed to contain many statements of Malkiel's ""A Random Walk Down Wall Street""." If you look at a trade grid you can see how this happens. If there are enough bids to cover all shares currently on the sell side at a certain price, those shares will be bought and increased price quotes will be shown for the bids and ask. If there are enough bids to cover this price, those will get bought and higher prices will be shown and this process will repeat until the sell side has more power than the buy side. It seems like this process is going on all day long with momentum either on the upside or downside. But I think that much of this bidding and selling is automatic and is being done by large trading firms and high tech computers. I also feel that many of these bids and asks are already programmed to appear once there is a price change. So once one price gets bought, computers will put in higher bids to take over asks. It's like a virtual war between trading firms and their computers. When more money is on the buy side the stock will go up, and vice versa. I sort of feel like this high-frequency trading is detrimental to the markets and doesn't really give everyone a fair shot. Retail investors do not have the resources and knowledge in order to do this sort of high frequency trading. It also seems to go against certain free market principles in my opinion. "I'm not sure the term actually has a clear meaning. We can think of ""what does this mean"" in two ways: its broad semantic/metaphorical meaning, and its mechanical ""what actual variables in the market represent this quantity"". Net buying/selling have a clear meaning in the former sense by analogy to the basic concept of supply and demand in equilibrium markets. It's not as clear what their meaning should be in the latter sense. Roughly, as the top comment notes, you could say that a price decrease is because of net selling at the previous price level, while a price rise is driven by net buying at the previous price level. But in terms of actual market mechanics, the only way prices move is by matching of a buyer and a seller, so every market transaction inherently represents an instantaneous balance across the bid/ask spread. So then we could think about the notion of orders. Actual transactions only occur in balance, but there is a whole book of standing orders at various prices. So maybe we could use some measure of the volume at various price levels in each of the bid/ask books to decide some notion of net buying/selling. But again, actual transactions occur only when matched across the spread. If a significant order volume is added on one side or the other, but at a price far away from the bid/offer - far enough that an actual trade at that price is unlikely to occur - should that be included in the notion of net buying/selling? Presumably there is some price distance from the bid/offer where the orders don't matter for net buying/selling. I'm sure you'd find a lot of buyers for BRK.A at $1, but that's completely irrelevant to the notion of net buying/selling in BRK.A. Maybe the closest thing I can think of in terms of actual market mechanics is the comparative total volumes during the period that would still have been executed if forced to execute at the end of period price. Assuming that traders' valuations are fixed through the period in question, and trading occurs on the basis of fundamentals (which I know isn't a good assumption in practice, but the impact of price history upon future price is too complex for this analysis), we have two cases. If price falls, we can assume all buyers who executed above the last price in the period would have happily bought at the last price (saving money), while all sellers who executed below the last price in the period would also be happy to sell for more. The former will be larger than the latter. If the price rises, the reverse is true." Im an actor preparing for a role. I play a trader in the UK during the late 80s. I have a very basic understanding of the stock market and am unsure what some of the dialogue is referring to. For example: “bid 28 at the figure” “sell at 3” “5 march at 28” “9 for 5” “bid 4 at 6” “closing out now at 4”. What do these numbers mean exactly. It doesn’t help that im Australian and this is a UK production, or that im an idiot