vania-janet/multiturn-rag-retrieval-data huggingface dataset:
A few observations - A limit order can certainly work, as you've seen.  I've put in such an order far beyond the true value, and gotten back a realistic bid/ask within 10 minutes or so. That at least gave me an idea where to set my limit.  When this doesn't work, an exercise is always another way to go. You'll get the full intrinsic value, but no time value, by definition.  Per your request in comment - You own a put, strike price $100. The stock (or ETF) is trading at $50. You buy the stock and tell the broker to exercise the put, i.e. deliver the stock to the buyer of the put.
A bid is an offer to buy something on an order book, so for example you may post an offer to buy one share, at $5. An ask is an offer to sell something on an order book, at a set price. For example you may post an offer to sell shares at $6. A trade happens when there are bids/asks that overlap each other, or are at the same price, so there is always a spread of at least one of the smallest currency unit the exchange allows. Betting that the price of an asset will go down, traditionally by borrowing some of that asset and then selling it, hoping to buy it back at a lower price and pocket the difference (minus interest). So, let's say as per your example you borrow 100 shares of company 'X', expecting the price of them to go down. You take your shares to the market and sell them - you make a market sell order (a market 'ask'). This matches against a bid and you receive a price of $5 per share. Now, let's pretend that you change your mind and you think the price is going to go up, you instantly regret your decision. In order to pay back the shares, you now need to buy back your shares as $6 - which is the price off the ask offers on the order book. Because of this spread, you have lost money. You sold at a low price and bought at a high price, meaning it costs you more money to repay your borrowed shares. So, when you are shorting you need the spread to be as tight as possible.
"I can address what it means to ""pick off"" all those trades... As quantycuenta & littleadv have said, it is absolutely true that professionals ""prey"" on less-sophisticated market participants. They aren't in the market for charity's sake. If you're not familiar with the definition of the word ""arbitrage"", look it up. One possible strategy that can be employed with HFT machinery in order to arbitrage successfully in the stock market is to 'intercept' orders that are placed on various exchanges. In order to do this, an HFT organization watches all the transactions at once to find opportunities to buy low and sell high. A good explanation of it is described here in this NY Times article; I'll paraphrase what that article lays out. Stocks are traded through multiple exchanges The first key point to understand is that stocks listed on one exchange (i.e. the NYSE) can be sold on multiple exchanges. That's where the actual ""I would like to sell 100 shares of Ford stock"" is matched with ""I would like to buy 100 shares of Ford stock."" There are multiple clearinghouses on the various exchanges. Your order gets presented to one exchange at a Time An ideal market maker would like to look at the order books for a given stock, say Ford, and see that in exchange A there's a sell order for 100 shares of F at $15.85, and in exchange B there's a buy order for 100 shares of F at $15.90. Arbitrage Market maker buys from A, sells in B, and pockets $0.05 * 100... $5. It's not much, but it was relatively risk free. Also, scale this up to the scale of the US' multiple stock exchanges, and there are lots of opportunities to make $5 every second. Computers are (of course) faster than people To tie it in completely with your question about 'picking off trades', HFT rigs can be set up and programmed to go faster than an average retail investor's order. Let's say you execute the trade to buy 100 shares @ $15.85 as a retail investor.
The first moment of trading usually occurs even later than that. It may take a few hours to balance the current buy/sell orders and open the stock. Watch CNBC when a hot IPO is about to open and you'll see the process in real time. If you miss it, look at a one day Yahoo chart to see when the open occurred.
RESPONSE TO QUESTION So if I understand correctly, the money gained through a direct market access model comes from other investors in the same CFD who happened to have invested in the ""wrong"" direction the asset was presumed to take. What happens then, if no one is betting in the opposite direction of my investment. Your understanding is correct. If literally nobody is betting in the opposite direction to you, then you will not be able to trade. This is true for any derivative market; if suddenly every single buyer were to remove their bids from the S&P futures, then no seller would be able to sell. This is a very extreme scenario, as the S&P futures market is incredibly liquid (loads of buyers and sellers at all times). However, if something like this does happen (the flash crash of 2010, for example), then the centralized futures exchanges such as the CME have safeguards in place - the market become locked-limit so that it can only fall so far, there may be no buyers below the lock limit price, but the market cannot fall through it. CFD providers are not obliged to provide such safeguards, which is why regulators in the US don't permit them to operate. It may be the case that if you're trying to buy a CFD for a thinly traded and ill-liquid stock there will be no seller available. One possibility is that the provider will offer a 'hybrid' model, and in the absence of an independent counter party they will take the opposite side of your bet, and then offset their risk by taking an opposing position in the underlying stock."
"EVERYONE buys at the ask price and sells at the bid price (no matter who you are). There are a few important things you need to understand. Example: EVE bid: 16.00 EVE ask: 16.25 So if your selling EVE at ""market price"" you are entering an ask equal to the highest bid ($16.00). If you buy EVE at ""market price"" you are entering a bid equal to the lowest ask price ($16.25). Its key to understand this rule: ""An order executes ONLY when both bid and ask meet. (bid = ask)."" So a market maker puts in a bid when he wants to buy but the trade only executes when an ASK price meets his BID price. When you see a quote for a stock it is the price of the last trade. So it is possible to have a quote higher or lower then both the bid and the ask."
"Most of the time* you're selling to other investors, not back to the company. The stock market is a collection of bid (buy offers) and asks (sell offers). When you sell your stock as a retail investor at the ""market"" price you're essentially just meeting whatever standing bid offers are on the market.  For very liquid stocks (e.g. Apple), you can pretty much always get the displayed price because so many stocks are being traded. However during periods of very high volatility or for low-volume stocks, the quoted price may not be indicative of what you actually pay.  As an example, let's say you have 5 stocks you're trying to sell and the bid-side order book is 2 stocks for $105, 2 for $100, and 5 for $95. In this scenario the quoted price will be $105 (the best bid price), but if you accept market price you'll settle 2 for 105, 2 for 100, and 1 for 95. After your sell order goes through, the new quoted price will be $95. For high volume stocks, there will usually be so many orders near the midpoint price ($105, in this case) that you won't see any price slippage for small orders.  You can also post limit orders, which are essentially open orders waiting to be filled like in the above example. They ensure you get the price you want, but you have no way to guarantee they'll be filled or not.  Edit: as a cool example, check out the bitcoin GDAX on coinbase for a live example of what the order book looks like for stocks. You'll see that the price of bitcoin will drift towards whichever direction has the less dense order book (e.g. price drifts upwards when there are far more bids than asks.)"
Firstly what are you trading that you could lose more than you put in? If you are simply trading stocks you will not lose more than you put in, unless you are trading on margin. A limit order is basically that, a limit on the maximum price you want your buy order bought at or the minimum price you want your sell order sold at. If you can't be glued to the screen all day when you place a limit order, and the market moves the opposite way, you may miss out on your order being executed. Even if you can be in front of the screen all day, you then have to decide if you want to chase the market of miss out on your purchase or sale. For example, if a stock is trading at $10.10 and you put a limit buy order to buy 1000 shares at or below $10.00 and the price keeps moving up to $10.20, then $10.30 and then $10.50, until it closes the day at $11.00. You then have the choice during the day to miss out on buying the shares or to increase your limit order in order to buy at a higher price. Sometime if the stock is not very liquid, i.e. it does not trade very often and has low volume, the price may hit $10.00 and you may only have part of your order executed, say 500 out of your 1000 shares were bought. This may mean that you may have to increase the price of your remaining order or be happy with only buying 500 shares instead of 1000. The same can happen when you are selling (but in reverse obviously). With market order, however, you are placing a buy order to buy at the next bid price in the depth or a sell order to sell at the next offer price in the depth. See the market depth table below: Note that this price depth table is taken before market open so it seems that the stock is somewhat illiquid with a large gap between the first and second prices in the buyers (bid) prices. When the market opened this gap is closed, as WBC is a major Australian bank and is quite liquid. (the table is for demonstration purposes only).
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.
If #2 is how it really worked I would approve.  In the real world, entities who have the money to purchase access have systems which are in a position to execute strategies which shave pennies of of people who want to make real trades. I want to sell for $61.15 and someone wants to buy for $61.10 and the HFT traders force both hands and make their money on that nickel in between us.
Purchases and sales from the same trade date will both settle on the same settlement date. They don't have to pay for their purchases until later either. Because HFT typically make many offsetting trades -- buying, selling, buying, selling, buying, selling, etc -- when the purchases and sales settle, the amount they pay for their purchases will roughly cancel with the amount they receive for their sales (the difference being their profit or loss). Margin accounts and just having extra cash around can increase their ability to have trades that do not perfectly offset. In practice, the HFT's broker will take a smaller amount of cash (e.g. $1 million) as a deposit of capital, and will then allow the HFT to trade a larger amount of stock value long or short (e.g. $10 million, for 10:1 leverage). That $1 million needs to be enough to cover the net profit/loss when the trades settle, and the broker will monitor this to ensure that deposit will be enough.
Quote driven markets are the predecessors to the modern securities market. Before electronic trading and HFTs specifically, trading was thin and onerous. Today, the average investor can open up a web page, type in a security, and buy at the narrowest spread permitted by regulators with anyone else who wants to take the other side. Before the lines between market maker and speculator became blurred to indistinction, a market maker was one who was contractually obligated to an exchange to provide a bid and ask for a given security on said exchange even though at heart a market maker is still simply a trader despite the obligation. A market maker would simultaneously buy a large amount of securities privately and short the same amount to have no directional bias, exposure to the direction of the security, and commence to making the market. The market maker would estimate its cost basis for the security based upon those initial trades and provide a bid and ask appropriate for the given level of volume. If volumes were high, the spread would be low and vice versa. Market makers who survived crashes and spikes would forgo the potential profit in always providing a steady price and spread, ie increased volume otherwise known as revenue, to maintain no directional bias. In other words, if there were suddenly many buyers and no sellers, hitting the market maker's ask, the MM would raise the ask rapidly in proportion to the increased exposure while leaving the bid somewhere below the cost basis. Eventually, a seller would arise and hit the MM's bid, bringing the market maker's inventory back into balance, and narrowing the spread that particular MM could provide since a responsible MM's ask could rise very high very quickly if a lack of its volume relative to its inventory made inventory too costly. This was temporarily extremely costly to the trader if there were few market makers on the security the trader was trading or already exposed to. Market makers prefer to profit from the spread, bidding below some predetermined price, based upon the cost basis of the market maker's inventory, while asking above that same predetermined cost basis. Traders profit from taking exposure to a security's direction or lack thereof in the case of some options traders.
Your question is unanswerable as you haven't provided enough information. I.e. If those shares cost $1000 and you have $50000 ( or any number above $1000) of cash available in the account then you can't possibly free ride. I think your understanding of the free ride rule is incorrect. Basically what this rule is stating is that you have to have the cash when the trade is placed in order to settle the trade. Otherwise you are taking on margin (which you can't do in a cash account). So at order entry you have to have the cash to cover the purchase so it's able to be settled. If you do, no problem and you can sell that stock before trade settlement. There is no law that says you have to hold it past trade settlement. However, you cannot spend the same dollar more than once before it settles.  This site does a good job explaining this more throughly with examples: http://www.invest-faq.com/articles/trade-day-free-ride.html
"....causes loses [sic] to others. Someone sells you a stock.  The seller receives cash.  You receive a stock certificate.  This doesn't imply a loss by either party especially if the seller sold the stock for more than his purchase price. A day trading robot can make money off of the price changes of a stock only if there are buyers and sellers of the stock at certain prices.  There are always two parties in any stock transaction: a buyer and a seller.  The day trading robot can make money off of an investment for 20 years and you could still make money if the investment goes up over the 20 years.  The day trading robot doesn't ""rob"" you of any profit."
"There are a few people that do this for a living. They are called ""market makers"" or ""specialists"" in a particular stock. First of all, this requires a lot of capital. You can get burned on a few trades, a process known as ""gambler's ruin,"" but if you have enough capital to weather the storm, you can make money. Second, you have to be ""licensed"" by the stock market authorities, because you need to have stock market trading experience and other credentials. Third, you are not allowed to buy and sell at will. In order to do your job, you have to ""balance the boat,"" that is buy, when others are selling, and sell, when others are buying, in order to keep the market moving in two directions. It's a tough job that requires a lot of experience, plus a license, but a few people can make a living doing this."
As I understand agency trading is where you execute an order on behalf a client, what I don't understand is what is where the skill comes in. You're not running a book, so you don't warehouse risk/manage it, and so where does the skill enter especially when it comes to stock trades?
"The reason for this is arbitrage. In an free and open market, investments that are certain to generate above-average profits would do so by being sold cheaply, while having a high return on investment after that. But in a free market, prices are set by supply and demand. There is a high demand and little supply for investments that would certainly outperform the market. The demand is in fact so high, that the purchase price rises to the point of eliminating that excess return. And with high-frequency automated trading, that price hike is instant. But who would even want to sell such guaranteed outperformers in the first place? Of course, there are uncertainties associated with stocks, and individual stocks therefore move independently. As ""the market"" is an average, some stocks will therefore beat the market over certain time periods. That's random statistical variation. The only realistic path to above-average returns is to accept higher risks. As discussed above, nobody wants to sell you safe bets. But risky bets are another matter. Different actors will price risk differently. If you aren't worried much about risk, you can pick up stocks that are cheap by your standards. That is possible only because such stocks aren't cheap by risk-averse standards.  Looking a bit deeper, we see that arbitrage works in a free market because there's essentially perfect information. But risk is precisely the absence of such information, and that can lead to price variations. Yet, as the lack of information means a lack of certainty, you can't use this to reliably beat the market."
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.
"Options have legitimate uses as a way of hedging a bet, but in the hands of anyone but an expert they're gambling, not investing. They are EXTREMELY volatile compared to normal stocks, and are one of the best ways to lose your shirt in the stock market yet invented. How options actually work is that you're negotiating a promise that, at some future date or range of dates, they will let you purchase some specific number of shares (call), or they will let you sell them that number of shares (put), at a price specified in the option contract. The price you pay (or are paid) to obtain that contract depends on what the option's seller thinks the stock is likely to be worth when it reaches that date. (Note that if you don't already own the shares needed to back up a put option, you're promising to pay whatever it takes to buy those shares so you can sell them at the agreed upon price.) Note that by definition you're betting directly against experts, as opposed to a normal investment where you're usually trying to ride along with the experts. You are claiming that you can predict the future value of the stock better than they can, and that you will make a profit (on the difference between the value locked in by the option and the actual value at that time) which exceeds the cost of purchasing the option in the first place. Let me say that again: the option's price will have been set based on an expert's opinion of what the stock is likely to do in that time. If they think that it's really likely to be up $10 per share when the option comes due (really unlikely for a $20 stock!!!), they will try to charge you almost $10 per share to purchase the option at the current price. ""Almost"" because you're giving them a guaranteed profit now and assuming all the risk. If they're less sure it will go up that much, you'll pay less for the option -- but again, you're giving them hard money now and betting that you can predict the probabilities better than they can. Unless you have information that the experts don't have -- in which case you're probably committing insider trading -- this is a very hard bet to win.