How do markets “factor in” a future event?
"At the most fundamental level, every market is comprised of buyers and selling trading securities. These buyers and sellers decide what and how to trade based on the probability of future events, as they see it. That's a simple statement, but an example demonstrates how complicated it can be. Picture a company that's about to announce earnings. Some investors/traders (from here on, ""agents"") will have purchased the company's stock a while ago, with the expectation that the company will have strong earnings and grow going forward. Other agents will have sold the stock short, bought put options, etc. with the expectation that the company won't do as well in the future. Still others may be unsure about the future of the company, but still expecting a lot of volatility around the earnings announcement, so they'll have bought/sold the stock, options, futures, etc. to take advantage of that volatility.  All of these various predictions, expectations, etc. factor into what agents are bidding and asking for the stock, its associated derivatives, and other securities, which in turn determines its price (along with overall economic factors, like the sector's performance, interest rates, etc.) It can be very difficult to determine exactly how markets are factoring in information about an event, though. Take the example in your question. The article states that if market expectations of higher interest rates tightened credit conditions... In this case, lenders could expect higher interest rates in the future, so they may be less willing to lend money now because they expect to earn a higher interest rate in the future. You could also see this reflected in bond prices, because since interest rates are inversely related to bond prices, higher interest rates could decrease the value of bond portfolios. This could lead agents to sell bonds now in order to lock in their profits, while other agents could wait to buy bonds because they expect to be able to purchase bonds with a higher rate in the future.  Furthermore, higher interest rates make taking out loans more expensive for individuals and businesses. This potential decline in investment could lead to decreased revenue/profits for businesses, which could in turn cause declines in the stock market. Agents expecting these declines could sell now in order to lock in their profits, buy derivatives to hedge against or ride out possible declines, etc. However, the current low interest rate environment makes it cheaper for businesses to obtain loans, which can in turn drive investment and lead to increases in the stock market. This is one criticism of the easy money/quantitative easing policies of the US Federal Reserve, i.e. the low interest rates are driving a bubble in the stock market. One quick example of how tricky this can be. The usual assumption is that positive economic news, e.g. low unemployment numbers, strong business/residential investment, etc. will lead to price increases in the stock market as more agents see growth in the future and buy accordingly. However, in the US, positive economic news has recently led to declines in the market because agents are worried that positive news will lead the Federal Reserve to taper/stop quantitative easing sooner rather than later, thus ending the low interest rate environment and possibly tampering growth.  Summary: In short, markets incorporate information about an event because the buyers and sellers trade securities based on the likelihood of that event, its possible effects, and the behavior of other buyers and sellers as they react to the same information. Information may lead agents to buy and sell in multiple markets, e.g. equity and fixed-income, different types of derivatives, etc. which can in turn affect prices and yields throughout numerous markets."
This is a great question for understanding how futures work, first let's start with your assumptions The most interesting thing here is that neither of these things really matters for the price of the futures.  This may seem odd as a futures contract sounds like you are betting on the future price of the index, but remember that the current price already includes the expectations of future earnings as well! There is actually a fairly simple formula for the price of a futures contract (note the link is for forward contracts which are very similar but slightly more simple to understand).  Note, that if you are given the current price of the underlying the futures price depends essentially only on the interest rate and the dividends paid during the length of the futures contract.  In this case the dividend rate for the S&P500 is higher than the prevailing interest rate so the futures price is lower than the current price.  It is slightly more complicated than this as you can see from the formula, but that is essentially how it works. Note, this is why people use futures contracts to mimic other exposures.  As the price of the future moves (pretty much) in lockstep with the underlying and sometimes using futures to hedge exposures can be cheaper than buying etfs or using swaps. Edit: Example of the effect of dividends on futures prices For simplicity, let's imagine we are looking at a futures position on a stock that has only one dividend (D) in the near term and that this dividend happens to be scheduled for the day before the futures' delivery date.  To make it even more simple lets say the price of the stock is fairly constant around a price P and interest rates are near zero.  After the dividend, we would expect the price of the stock to be P' ~ P - D as if you buy the stock after the dividend you wouldn't get that dividend but you still expect to get the rest of the value from additional future cash flows of the company. However, if we buy the futures contract we will eventually own the stock but only after the dividend happens.  Since we don't get that dividend cash that the owners of the stock will get we certainly wouldn't want to pay as much as we would pay for the stock (P).  We should instead pay about P' the (expected) value of owning the stock after that date.   So, in the end, we expect the stock price in the future (P') to be the futures' price  today (P') and that should make us feel a lot more comfortable about what we our buying.  Neither owning the stock or future is really necessarily favorable in the end you are just buying slightly different future expected cash flows and should expect to pay slightly different prices. There is no way to find out what future will be if you have only quote from past. In other words, nobody is able to trade history successfully and nobody will be able, ever. Quote's movement is not random. Quote is not price. Because brokerage account is not actual money. Any results in past do not guarantee you anything. Brokerage accounts should only have portions of money which you are ready to loose completely. Example: Investment firms recommended buying falling Enron stocks, even when it collapsed 3 times, then - bankrupt, suddenly. What a surprise! There are multiple factors at play that drive stock price movements, but one that can be visualized is that stocks can be priced relative to other (similar stocks).  When one stock price goes up without fundamental changes (i.e. daily market noise/movements), it becomes slightly more expensive relative to it's peers.  Opportunists will sell the now slightly more expensive stock, while others may buying the slightly cheaper (relatively) peer stock.    Imagine millions of transactions like this happening throughout each hour, downward selling pressure on a stock that rises too fast in value relative to it's peers or the market, and upward buying pressure on stocks that are relatively cheaper than it's peers.  It pushes two stocks towards an equilibrium that is directionally the same.    Another way to think of it is lets say tomorrow there is $10B in net new dollars moved into buy orders for stocks that comes from net selling of bonds (this is also partly why bonds/stocks are generally inversely related).  That money goes to buys stocks ABC, XYZ, EFG.  As the price of those goes up with more buying pressure, stocks JKL, MNO, PQR are relatively a tad cheaper, so some money starts to flow into there.  Repeat until you get a large majority of the stocks that buyers are willing to buy and you can see why stocks move in the same direction a lot of times. There are some important thing you need to understand about bonds, and how they work:  * A bond doesn't need an active market - like a stock, for example - to have value.    * Nonetheless, there exist active markets for all of these bonds.    * The purpose of buying these bonds was not to step in due to the absence of a market.  Rather, the purpose was to deliberately bid up the price of these bonds (ahead of the market), causing their price to rise and yields (interest rates) to drop.  * The Fed can hold any and all of these bonds to maturity, while receiving contractual payments all the while, and never sell a single bond back to the market. It might be clearer to think of it as price going up when a dividend is expected, since that's money you'll get right back. As the delay before the next dividend payment increases, that becomes less of a factor, This question is impossible answer for all markets but there are 2 more possibilities in my experience: "Trends and trajectories mean nothing when the market is at an inflection point. You can't predict the future when you don't know what the players have planned.  EDIT: Make that ""can't know"", since even the big players don't know what they are doing next." News-driven investors tend to be very short-term focussed investors. They often trade by using index futures (on the S&P 500 index for instance). There's an interview with Andrew Lo on the WSJ that's worth a listen. One idea he touched on briefly is how the rise of index funds may be creating an investor monoculture. If this is the case, then he thinks it could lead to more market volatility. Interesting stuff.  http://www.wsj.com/podcasts/andrew-w-lo-talks-how-to-evolve-with-adaptive-markets/4B141ED2-23EA-409E-BFEE-96791EEB473E.html I understand now. Thank you. How important is the existence of effective price discovery tools in a market?   And the example that you gave of a farmer is good, but when I as the owner of a company, get futures regarding, say, the stocks that I own of my company, won't that be insider trading if I do that after knowing that the value of my stocks will fall? If people assume price discovery in this case, won't they also have to assume that I am doing insider trading? "Nobody has mentioned the futures market yet. Although the stock market closes at 4pm, the futures market continues trading 24 hours a day and 5.5 days a week. Amongst the products that trade in the future market are stock index futures.  That includes the Dow Jones, the S&P 500. These are weighted averages of stocks and their sectors. You would think that the price of the underlying stock dictates the price of the average, but in this day and age, the derivative actually changes the value of the underlying stock due to a very complex combination of hedging practices. (this isn't meant to be vague and mysterious, it is ""delta hedging"") So normal market fluctuations coupled with macroeconomic events affect the futures market, which can ripple down to individual stocks. Very popular stocks with large market caps will most certainly be affected by futures market trading. But it is also worth mentioning that futures can function completely independently of a ""spot"" price. This is where things start to get complicated and long winded. The futures market factor is worth mentioning because it extends even outside of the aftermarket and pre-market hours of stock trading." People are trying ideas like this, actually.  Though they generally aren't very public about it.  While keshlam ventures into hyperbole when mentioning Watson, he is certainly correct human language parsing is a extremely hard problem. While it is not always true that the big players will know before the news (sometimes that would qualify as insider trading).  The volume spike that you mention generally comes as the news arrives to the major (and minor) players.  So, if you have an algorithm run after the volume spike the price will likely have adjusted significantly already. You can try to avoid this by constantly scanning for news on a set of stocks however this becomes an even harder problem.  Or maybe by becoming more specific and parsing known important and specific news sources (farm report for instance) and trying to do so faster than anyone else.  These are some methods people use to not be too late. Recommended? There's really no perfect answer. You need to know the motivations of the participants in the markets that you will be participating in. For instance, the stock market's purpose is to raise capital (make as much money as possible), whereas the commodities-futures market's purpose is to hedge against producing actual goods. The participants in both markets have different reactions to changes in price. "Strategy would be my top factor.  While this may be implied, I do think it helps to have an idea of what is causing the buy and sell signals in speculating as I'd rather follow a strategy than try to figure things out completely from scratch that doesn't quite make sense to me. There are generally a couple of different schools of analysis that may be worth passing along: Fundamental Analysis:Fundamental analysis of a business involves analyzing its financial statements and health, its management and competitive advantages, and its competitors and markets. When applied to futures and forex, it focuses on the overall state of the economy, interest rates, production, earnings, and management. When analyzing a stock, futures contract, or currency using fundamental analysis there are two basic approaches one can use; bottom up analysis and top down analysis. The term is used to distinguish such analysis from other types of investment analysis, such as quantitative analysis and technical analysis. Technical Analysis:In finance, technical analysis is a security analysis methodology for forecasting the direction of prices through the study of past market data, primarily price and volume. Behavioral economics and quantitative analysis use many of the same tools of technical analysis, which, being an aspect of active management, stands in contradiction to much of modern portfolio theory. The efficacy of both technical and fundamental analysis is disputed by the efficient-market hypothesis which states that stock market prices are essentially unpredictable. There are tools like ""Stock Screeners"" that will let you filter based on various criteria to use each analysis in a mix.  There are various strategies one could use.  Wikipedia under Stock Speculator lists: ""Several different types of stock trading strategies or approaches exist including day trading, trend following, market making, scalping (trading), momentum trading, trading the news, and arbitrage.""  Thus, I'd advise research what approach are you wanting to use as the ""Make it up as we go along losing real money all the way"" wouldn't be my suggested approach. There is something to be said for there being numerous columnists and newsletter peddlers if you want other ideas but I would suggest having a strategy before putting one's toe in the water." While there are lots of really plausible explanations for why the market moves a certain way on a certain day, no one really knows for sure.  In order to do that, you would need to understand the 'minds' of all the market players.  These days many of these players are secret proprietary algorithms.  I'm not quibbling with the specifics of these explanations (I have no better) just pointing out that these are just really hypotheses and if the market starts following different patterns, they will be tossed into the dust bin of 'old thinking'. I think the best thing you can explain to your son is that the stock market is basically a gigantic highly complex poker game.  The daily gyrations of the market are about individuals trying to predict where the herd is going to go next and then after that and then after that etc. If you want to help him understand the market, I suggest two things.  The first is to find or create a simple market game and play it with him.  The other would be to teach him about how bonds are priced and why prices move the way they do.  I know this might sound weird and most people think bonds are esoteric but there are bonds have a much simpler pricing model based on fundamental financial logic.  It's much easier then to get your head around the moves of the bond markets because the part of the price based on beliefs is much more limited (i.e. will the company be able pay & where are rates going.)  Once you have that understanding, you can start thinking about the different ways stocks can be valued (there are many) and what the market movements mean about how people are valuing different companies. With regard to this specific situation, here's a different take on it from the 'priced in' explanation which isn't really different but might make more sense to your son: Pretend for a second that at some point these stocks did move seasonally.  In the late fall and winter when sales went up, the stock price increased in kind.  So some smart people see this happening every year and realize that if they bought these stocks in the summer, they would get them cheap and then sell them off when they go up.  More and more people are doing this and making easy money.  So many people are doing it that the stock starts to rise in the Summer now.  People now see that if they want to get in before everyone else, they need to buy earlier in the Spring.  Now the prices start rising in the Spring.  People start buying in the beginning of the year... You can see where this is going, right?  Essentially, a strategy to take advantage of well known seasonal patterns is unstable.  You can't profit off of the seasonal changes unless everyone else in the market is too stupid to see that you are simply anticipating their moves and react accordingly.