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.)"
"That article, like almost any article written by a non-expert and quoting only ""research"" from lobbying groups, hugely misses the point. The vast majority of orders that end up being cancelled are cancelled as a standard part of exchanges' official market-maker programs. Each exchange wants you and me to know that it has liquidity -- that when we go to buy or sell some stock, there will be someone waiting on the other side of the trade.  So the exchange pays (via lowered fees or even rebates) hundreds of registered market makers to constantly have orders resting in each product's order book within a few ticks of the current NBBO or the last trade price.  That way, if everyone else should suddenly disappear from the market, you and I will still be able to trade our shares for a price somewhat close to the last trade price. But market makers who are simply acting in this ""backstop"" role don't actually want to have their orders filled, because those orders will almost always lose them money. So as prices rise and fall (as much as tens of times per second), the market makers need to cancel their resting orders (so they don't get filled) and add new ones at new prices (so they meet their obligations to the exchange).  And because the number of orders resting in any given product's order book is vastly larger than the number of actual trades that take place in any given time period, naturally the number of cancellations is also going to hugely outweigh the number of actual trades.  As much as 97% to 3% (or even more). But that's completely fine! You and I don't have to care about any of that.  We almost never need the market makers to be there to trade with us.  They're only there as a backstop.  There's almost always plenty of organic liquidity for us to trade against.  Only in the rare case where liquidity completely dries up do we really care that the registered market makers are there.  And in those cases (ideally) the market makers can't cancel their orders (depending on how well the exchange has set up its market maker program). So, to answer your question, the effect of standard order cancellation on a stock is essentially none.  If you were to visualize the resting orders in a product's book as prices moved up and down, you would essentially see a Gaussian distribution with mean at the last trade price, and it would move up and down with the price.  That ""movement"" is accomplished by cancellations followed by new orders. P.S. As always, keep in mind that your and my orders almost never actually make it to a real stock exchange anymore.  Nowadays they are almost always sent to brokers' and big banks' internal dark pools.  And in there you and I have no idea what shenanigans are going on.  As just one example, dark pools allow their operators and (for a fee) other institutional participants access to a feature called last look that allows them to cancel their resting order as late as after your order has been matched against it! :( Regarding the question in your comment ... If Alice is sending only bona fide orders (that is, only placing an order at time T if, given all the information she has at time T, she truly wants and intends for it to be filled) then her cancellation at a later time actually adds to the effectiveness of and public perception of the market as a tool for price discovery (which is its ultimate purpose). [In the following example imagine that there are no such things as trading fees or commissions or taxes.] Let's say Alice offers to buy AAPL at $99.99 when the rest of the market is trading it for $100.00.  By doing so she is casting her vote that the ""fair value"" of a share of AAPL is between $99.99 and $100.00. After all, if she thought the fair value of a share of AAPL was higher --  say, between $100.00 and $100.01 -- then she should be willing to pay $100.00 (because that's below fair value) and she should expect that other people in the market will not soon decide to sell to her at $99.99. If some time later Alice does decide that the fair value of AAPL is between $100.00 and $100.01 then she should definitely cancel her order at $99.99, for exactly the reason discussed above.  She probably won't get filled at $99.99, and by sitting there stubbornly she's missing out (potentially forever) on the possibility to make a profit. Through the simple act of cancelling her $99.99 order, Alice is once again casting a vote that she no longer thinks that's AAPL's fair value.  She is (very slightly) altering the collective opinion of the entire market as to what a share of AAPL is worth.  And if her cancellation then frees her up to place another order closer to her perceived fair value (say, at $100.00), then that's another vote for her honest optinion about AAPL's price. Since the whole goal of the market is to get a bunch of particpants to figure out the fair value of some financial instrument (or commodity, or smart phone, or advertising time, etc.), cancellations of honest votes from the past in order to replace them with new, better-informed honest votes in the present can only be a good thing for the market's effectiveness and perceived effectiveness. It's only when participants start sending non-honest votes (non bona fide orders) that things start to go off the rails.  That's what @DumbCoder was referring to in his comment on your original question." They've been around long enough now for there to be past performance figures you can google for. I think you'll find the results aren't very encouraging. I personally don't think there's a huge risk that the robots will lose all your money, but there's every reason to expect they aren't likely to perform better than traditional managers or beat the market. At the end of the day the robots are employing a lot of analysis and management techniques that traditional managers have been using, and since traditional managers use computers to do it efficiently there's not much gain IMO. Yes in theory labour is expensive so cutting it out is good, but in practise, in this case, the amount of money being managed is huge and the human cost is pretty insignificant. I personally don't believe that the reduced fees represent the cost of the human management, I think it's just marketing. There might be some risk that the robots can be 'gamed' but I doubt the potential is very great (your return might in theory be a fraction of a percent less over time because it's going on). The problem here is that the algorithms are functionally broadly known. No doubt every robo adviser has its own algorithms that in theory are the closely guarded secret, but in reality a broad swath of the functional behaviour will be understood by many people in the right circles, and that gives rise to predictability, and if you can predict investment/trading patterns you can make money from those patterns. That means humans making money (taking margin away) from the robots, or robots making money from other robots that are behind the curve. If robo advisers continue to take off I would expect them to under perform more and more. That metric is not very useful for anything other than very extremely long trading periods. Most strategies or concerned with price movement over much shorter time frames, 15 mins, 1 hr, 4 hr, daily, weekly, monthly. The MA or moving average is a trend following lagging indicator used to smooth out price fluctuations and more accurately reflect the price of trading instrument such as a stock (AAPL), commodity, or currency pair. Traders are generally concerned with current market trends and price action of the instrument they are trading. As such, an extremely long MA (average daily price, over a period of 365 days) are generally not that important. What if there is only one trading day and the volume is smaller than   the open interest on that one trading day. This is assuming there is   no open interest before that day? I pulled this from a comment. This can't happen. We have zero open interest on day one. On day 2, I buy 10 contracts. Volume is 10 and now open interest is also 10. Tomorrow, if I don't sell, open interest starts at 10 and will rise by whatever new contracts are traded.   This is an example. I removed the stock name. This happens to be the Jan'17 expiration. The 10 contract traded on the $3 strike happen to be mine. You can see how open interest is cumulative, representing all outstanding contracts. It's obvious to me the shares traded as high as $5 at some point which created the interest (i.e. the desire) to trade this strike. Most activity tends to occur near the current price. "You can infer some of the answers to your questions from the BATS exchange's market data page and its associated help page.  (I'm pretty sure a page like this exists on each stock exchange's website; BATS just happens to be the one I'm used to looking at.) The Matched Volume section refers to all trades on a given date that took place on ""lit"" exchanges; that is, where a public protected US stock exchange's matching engine helped a buyer and a seller find each other.  Because there are exactly 11 such exchanges in existence, it's easy to show 100% of the matched volume broken down into 11 rows. The FINRA & TRF Volume section refers to all trades on a given date that took place on ""non-lit"" exchanges.  These types of trades include dark pool volume and any other trade that is not required to take place in public but is required to be reported (the R in TRF) to FINRA.  There are three venues via which these trades may be reported to FINRA -- NASDAQ's, NYSE's, and FINRA's own ADF.  They're all operated under the purview of FINRA, so the fact that they're ""located at"" NASDAQ or NYSE is a red herring.  (For example, from the volume data it's clear that the NASDAQ facility does not only handle NASDAQ-listed (Tape C) securities, nor does the NYSE facility only handle NYSE-listed (Tape A) securities or anything like that.) The number of institutions reporting to each of the TRFs is large -- many more than the 11 public exchanges -- so the TRF data is not broken down further.  (Also I think the whole point of the TRFs is to report in secret.)  I don't know enough details to say why the NASDTRF has always handled more reporting volume than the other two facilities.  Of course, since we can't see inside the TRF reporting anyway, it's sort of a moot point." This is often the case where traders are closing out short positions they don't want to hold overnight, for a variety of reasons that matter to them.  Most frequently, this is from day traders or high-frequency traders settling their accounts before the markets close. I disagree strongly with the other two answers posted thus far. HFT are not just liquidity providers (in fact that claim is completely bogus, considering liquidity evaporates whenever the market is falling). HFT are not just scalping for pennies, they are also trading based on trends and news releases. So you end up having imperfect algorithms, not humans, deciding the price of almost every security being traded. These algorithms data mine for news releases or they look for and make correlations, even when none exist.  The result is that every asset traded using HFT is mispriced. This happens in a variety of ways. Algos will react to the same news event if it has multiple sources (Ive seen stocks soar when week old news was re-released), algos will react to fake news posted on Twitter, and algos will correlate S&P to other indexes such as VIX or currencies. About 2 years ago the S&P was strongly correlated with EURJPY. In other words, the American stock market was completely dependent on the exchange rate of two currencies on completely different continents. In other words, no one knows the true value of stocks anymore because the free market hasnt existed in over 5 years. 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.