Why there's always a very huge volume of trades for AAPL every day before market close?
"A huge amount of money in all financial markets is from institutional investors, such as mutual funds, government pension plans, sovereign wealth funds, etc.  For various reasons these funds do all of their trading at the end of the day.  They care primarily that their end-of-day balances are in line with their targets and are easy to audit and far less about ""timing the market"" for the best possible trades. So, if you're looking at a stock that is owned by many institutional investors -- such as a stock (like AAPL) that makes up a significant portion of an index that many funds track -- there will be a huge amount of activity at this time relative to stocks that are less popular among institutions. Even just in its introduction this paper (PDF) gives a fair overview of other reasons why there's a lot of trading at end-of-day in general. (In fact, because of all this closing activity and the reliance on end-of-day prices as signposts for financial calculations, the end-of-day has for decades been the single most fraud-ridden time of the trading day.  Electronic trading has done away with a lot of the straight-up thievery that floor traders and brokers used to get away with at the expense of the public, but it still exists.  See, for example, any explanation of the term banging the close, or the penalties against 6 banks just last month for manipulating the FX market at the close.)"
Buying stocks is like an auction. Put in the price you want to pay and see if someone is willing to sell at that price.  Thing to remember about after hours trading; There is a lot less supply so there's always a larger bid/ask price spread. That's the price brokers charge to handle the stocks they broker over and above the fee.  That means you will always pay more after the market closes. Unless it is bad news, but I don't think you want to buy when that happens. I think a lot of the after market trading is to manipulate the market. Traders drive up the price overnight with small purchases then sell their large holdings when the market opens. I would say the most challenging fact for this assertion is that HFT firms operate with extremely limited capital bases. For a stock with say 10m shares ADV, even a very large and successful HFT strategy might use a position limit of no more than 5000 shares.  That is to say if you sum up and net the buys and sells for a stock across the day the HFT firm will never exceed 10,000 shares (2x position limits assuming it completely flipped) on a stock that trades 10,000,000 shares on a given day. The high volumes are attained through high turnover, the strategy might trade up to 500,000 shares (or 5% of the volume) attaining a 50x turnover.  But that brings me back to the original point. In the market microstructure literature market impact generally has been found to scale linearly or even sub-linearly for net volume executed.   If I alternate between thousands of 1 lot buy and sell orders, it would be very difficult for me to move the market because the market impact of every one of my buy orders roughly cancels the market impact of my almost exactly equal number of sell orders.   There might be a higher-order mechanism at work, but I'm genuinely curious what you think it might be. How could strategies that attain such small net positions have such out-sized impact on market direction? Trading at the start of the day is highest because of news flows that may have come after the close of the previous day.  And trading at the end of the day is highest because of expected news flows after closing hours. Moreover, there are many day traders who buy in the morning without making any payment for purchase and such traders have to sell by evening or else they will have to make the payment for the purchases which they have made. "During market hours, there are a lot of dealers offering to buy and sell all exchange traded stocks. Dealers don't actually care about the company's fundamentals and they set their prices purely based on order flow. If more people start to buy than sell, the dealer notices his inventory going down and starts upping the price (both his bid and ask). There are also traders who may not be ""dealers"", but are willing to sell if the price goes high enough or buy if the price goes low enough. This keeps the prices humming along smoothly. During normal trading hours, if you buy something and turn around and sell it two minutes later, you'll probably be losing a couple cents per share. Outside normal market hours, the dealers who continue to have a bid and ask listed know that they don't have access to good price information --  there isn't a liquid market of continuous buying and selling for the dealer to set prices he considers safe. So what does he do? He widens the spread. He doesn't know what the market will open tomorrow at and doesn't know if he'll be able to react quickly to news. So instead of bidding $34.48 and offering at $34.52, he'll move that out to $33 and $36. The dealer still makes money sometimes off this because maybe some trader realized that he has options expiring tomorrow, or a short position that he's going to get a margin call on, or some kind of event that pretty much forces him to trade. Or maybe he's just panicking and overreacting to some news. So why not trade after hours? Because there's no liquidity, and trading when there's no liquidity costs you a lot." One of the fundamental of technical analysis suggests that holding a security overnight represents a huge commitment.  Therefore it would follow that traders would tend to close their positions prior to market close and open them when it opens. the data source is the same as the live market trading. pre and after market trading are active markets and there are actual buyers and sellers getting their orders matched. "I'll answer this question: ""Why do intraday traders close their position at then end of day while most gains can be done overnight (buy just before the market close and sell just after it opens). Is this observation true for other companies or is it specific to apple ?"" Intraday traders often trade shares of a company using intraday leverage provided by their firm. For every $5000 dollars they actually have, they may be trading with $100,000, 20:1 leverage as an example. Since a stock can also decrease in value, substantially, while the markets are closed, intraday traders are not allowed to keep their highly leveraged positions opened. Probabilities fail in a random walk scenario, and only one failure can bankrupt you and the firm." From March 26th to May 3rd FACE had an average trade volume of 11,657 shares. May 4th Bloomberg published its widely reported [article](http://www.bloomberg.com/news/2012-05-03/zuckerberg-s-facebook-ipo-will-make-him-richer-than-ballmer.html) about how the upcoming Facebook IPO would make Zuckerberg one of the richest people in the world. On May 4th, 212,000 shares of FACE were traded (an 18x increase) and the price jumped from 3.10 to 3.79, up 22%.  Maybe it's not that surprising, considering even news articles in [Yahoo! Finance](http://finance.yahoo.com/news/facebook-underwriters-1-1-percent-010320322.html) can't keep the companies straight.  Still, if you accidentally bought FACE it's not all that bad. In fact, [you're doing much better](http://finance.yahoo.com/echarts?s=FB+Interactive#symbol=fb;range=20120518,20120601;compare=face;).  Yes, FACE's 10-Q came out the previous day, but past 10-Q releases didn't result in any sudden increase in trading volume at all: [11/3/2011](http://finance.yahoo.com/echarts?s=FACE+Interactive#symbol=face;range=20111018,20111111;), [8/4/2011](http://finance.yahoo.com/echarts?s=FACE+Interactive#symbol=face;range=20110718,20110811;), [5/5/2011](http://finance.yahoo.com/echarts?s=FACE+Interactive#symbol=face;range=20110418,20110511;) "All public US equity exchanges are closed on the 9 US trading holidays (see below) and open on all other days.  Exchanges also close early (13:00 ET) on the Friday after Thanksgiving and on the day before Independence Day if Independence Day is being observed on a Tuesday, Wednesday, Thursday, or Friday.  (Some venues have extended trading hours as a matter of course; for them an ""early close"" might be later than 13:00 ET.) To answer the second question, yes, if you know NASDAQ's or AMEX's holiday schedule, then you know NYSE's (modulo the timing of their early close).  I'm not sure about the options exchanges; they're not regulated the same way and are a good example of exchanges with extended trading hours in the first place. The US trading holidays are as follows.  Note that trading holidays are not the same as federal or bank holidays, which include Columbus Day and Veterans Day but do not include Good Friday." "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." You may simply be asking why stocks 'gap up' or 'gap down' when the stock market opens. This is because the price adjusts to news that occurred while the exchanges were closed overnight. Perhaps Asian stocks crashed, or perhaps a news story was released in the New York Times about some major company. There are thousands of factors that affect market sentiment, and the big gaps that happen at the open of every trading day is the price of the stocks catching up to those factors. Graphs are nothing but a representation of data. Every time a trade is made, a point is plotted on the graph. After points are plotted, they are joined in order to represent the data in a graphical format.  Think about it this way.  1.) Walmart shuts at 12 AM. 2.)Walmart is selling almonds at $10 a pound.  3.) Walmart says that the price is going to reduce to $9 effective tomorrow. 4.) You are inside the store buying almonds at 11:59 PM.  5.) Till you make your way up to the counter, it is already 12:01 AM, so the store is technically shut. 6.) However, they allow you to purchase the almonds since you were already in there.  7.) You purchase the almonds at $9 since the day has changed. 8.) So you have made a trade and it will reflect as a point on the graph. 9.) When those points are joined, the curves on the graph will be created. 10.) The data source is Walmart's system as it reflects the sale to you. ( In your case the NYSE exchange records this trade made). Buying a stock is just like buying almonds. There has to be a buyer. There has to be a seller. There has to be a price to which both agree. As soon as all these conditions are met, and the trade is made, it is reflected on the graph. The only difference between the graphs from 9 AM-4 PM, and 4 PM-9 AM is the time. The trade has happened regardless and NYSE(Or any other stock exchange) has recorded it! The graph is just made from that data. Cheers. "Can you give me a rundown of what I'm seeing?  Is this basically a super zoomed in tracker of a current stock or something?  Where a stock fluctuates a few cents up/down on the day, and you just trade before it goes down, then trade as it goes up or what?  EDIT: Is this really live?  Can you say, ""Yes this is live narwalls""" "First it is worth noting the two sided nature of the contracts (long one currency/short a second) make leverage in currencies over a diverse set of clients generally less of a problem.  In equities, since most margin investors are long ""equities"" making it more likely that large margin calls will all be made at the same time. Also, it's worth noting that high-frequency traders often highly levered make up a large portion of all volume in all liquid markets ~70% in equity markets for instance.  Would you call that grossly artificial?  What is that volume number really telling us anyway in that case? The major players holding long-term positions in the FX markets are large banks (non-investment arm), central banks and corporations and unlike equity markets which can nearly slow to a trickle currency markets need to keep trading just for many of those corporations/banks to do business.  This kind of depth allows these brokers to even consider offering 400-to-1 leverage.  I'm not suggesting that it is a good idea for these brokers, but the liquidity in currency markets is much deeper than their costumers." Buying pressure means there are more interested buyers than there are ready sellers putting upward pressure on prices. That might include institutional buyers who are slowly executing buy orders because they still want the best prices possible without clearing out the market. Buying pressure doesn't have to be related to volume at all. If everyone who owns shares think they are going to be worth far more than recent market prices, they will not offer them for sale. That means there is more demand to buy than there is a supply of shares to be bought. That condition can exist regardless of trading volume.