How does a stock operate when it is listed between two exchanges?
Say a stock is listed in Nasdaq, and the same company has a stock listed in Tsx. Does the Nasdaq price affect the Tsx price as trading commences? Not directly. Basically, an exchange is a market, and the price is defined only by supply and demand in that market. However, any substantial price differential for a commodity traded in multiple market creates an arbitrage opportunity, and there are many traders whose job it is exactly to find and use such opportunities. Their activity in turn has the effect of reducing the price differentials to the point where transaction costs make them unprofitable. With high-frequency traders around, the time for a price differential to disappear is nowadays measured in milliseconds. If a trader buys from one exchange, will it affect the price of the other? Only through the mechanism mentioned above.  Are there any benefits to being listed in two exchanges? It increases the liquidity of a stock.
Futures exchanges are essentially auction houses facilitating a two-way auction. While they provide a venue for buyers and sellers to come together and transact (be that a physical venue such as a pit at the CME or an electronic network such as Globex), they don't actively seek out or find buyers and sellers to pair them together. The exchanges enable this process through an order book. As a futures trader you may submit one of two types of order to an exchange: Market Order - this is sent to the exchange and is filled immediately by being paired with a limit order.   Limit Order - this is placed on the books of the exchange at the price you specify. If other participants enter opposing market orders at this price, then their market order will be paired with your limit order. In your example, trader B wishes to close his long position. To do this he may enter a market sell order, which will immediately close his position at the lowest possible buy limit price, or he may enter a limit sell order, specifying the price at or above which he is willing to sell. In the case of the limit order, he will only sell and successfully close his position if his order becomes the lowest sell order on the book. All this may be a lot easier to understand by looking at a visual image of an order book such as the one given in the explanation that I have published here: Stop Orders for Futures Finally, not that as far as the exchange is concerned, there is no difference between an order to open and an order to close a position. They're all just 'buy' or 'sell' orders. Whether they cause you to reduce/exit a position or increase/establish a position is relative to the position you currently hold; if you're flat a buy order establishes a new position, if you're short it closes your position and leaves you flat. NYSE and Nasdaq are secondary markets where stocks are bought or sold. The process of creating new stocks via IPO or private placements etc are called Private Market. It doesn't matter which exchange a share was purchased through (or if it was even purchased on an exchange at all--physical share certificates can be bought and sold outside of any exchange). A share is a share, and any share available for purchase in New York is available to be purchased in London. Buying all of a company's stock is not something that can generally be done through the stock market. The practical way to accomplish buying a company out is to purchase a controlling interest, or enough shares to have enough votes to bind the board to a specific course of action. Then vote to sell all outstanding shares to another company at a particular fixed price per share. Market capitalization is an inaccurate measure of the size of a company in the first place, but if you want to quantify it, you can take the number of outstanding shares (anywhere and everywhere) and multiply them by the price on any of the exchanges that sell it. That will give you the market capitalization in the currency that is used by whatever exchange you chose. Exchange traded options are issued in a way that there is no counter party risk.  Consider, stocks and options are held in street name. So, for example, if I am short and you are long shares, no matter what happens on my end, your shares are yours.  To be complete, it's possible to enter into a direct deal, where you have a contract for some non-standard option, but that would be very rare for the average investor. There is no one answer to this question, but there are some generalities. Most exchanges make a distinction between the passive and the aggressive sides of a trade.  The passive participant is the order that was resting on the market at the time of the trade.  It is an order that based on its price was not executable at the time, and therefore goes into the order book.  For example, I'm willing to sell 100 shares of a stock at $9.98 but nobody wants to buy that right now, so it remains as an open order on the exchange. Then somebody comes along and is willing to meet my price (I am glossing over lots of details here).  So they aggressively take out my order by either posting a market-buy, or specifically that they want to buy 100 shares at either $9.98, or at some higher price. Most exchanges will actually give me, as the passive (i.e. liquidity making) investor a small rebate, while the other person is charged a few fractions of a cent.  Google found NYSEArca details, and most other exchanges make their fees public as well.  As of this writing the generic price charged/credited: But they provide volume discounts, and many of the larger deals do fall into another tier of volume, which provides a different price structure. "When there is a trade the shares were both bought and sold. In any trade on the secondary market there has to be both a buyer and a seller for the trade to take place. So in ""lasttradesize"" a buyer has bought the shares from a seller." You can check whether the company whose stock you want to buy is present on an european market. For instance this is the case for Apple at Frankfurt. "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." "I can see two possibilities. Either a deal is struck that someone (the company itself, or a large owner) buys out the remaining shares. This is the scenario @mbhunter is talking about, so I won't go too deeply into it, but it simply means that you get money in your bank account for the shares in question the same as if you were to sell them for that price (in turn possibly triggering tax effects, etc.). I imagine that this is by far the most common approach. The other possibility is that the stock is simply de-listed from a public stock exchange, and not re-listed elsewhere. In this case, you will still have the stock, and it will represent the same thing (a portion of the company), but you will lose out on most of the ""market"" part of ""stock market"". That is, the shares will still represent a monetary value, you will have the same right to a portion of the company's profits as you do now, etc., but you will not have the benefit of the market setting a price per share so current valuation will be harder. Should you wish to buy or sell stock, you will have to find someone yourself who is interested in striking a deal with you at a price point that you feel comfortable with." This is just a shot in the dark but it could be intermarket data. If the stock is interlisted and traded on another market exchange that day then the Yahoo Finance data feed might have picked up the data from another market. You'd have to ask Yahoo to explain and they'd have to check their data. "In the US there is only one stock market (ignoring penny stocks) and handfuls of different exchanges behind it.  NYSE and NASDAQ are two different exchanges, but all the products you can buy on one can also be bought on the other; i.e. they are all the same market.  So a US equities broker cannot possibly restrict access to any ""markets"" in the US because there is only one. (Interestingly, it is commonplace for US equity brokers to cheat their customers by using only exchanges where they -- the brokers -- get the best deals, even if it means your order is not executed as quickly or cheaply as possible.  This is called payment for order flow and unfortunately will probably take an Act of Congress to stop.) Some very large brokers will have trading access to popular equity markets in other countries (Toronto Stock Exchange, Mexico Stock Exchange, London Stock Exchange) and can support your trades there.  However, at many brokers or in less popular foreign markets this is usually not the case; to trade in the average foreign country you typically must open an account with a broker in that country." "The case you are looking at is rather special, because the Chinese government for the longest time did not allow foreigners to invest in Chinese stocks. The ADRs explained in @DStanley's answer are a way around that restriction; recently there are some limited official ways,  In general, it is perfectly normal for a stock to appear on different exchanges, in different currencies, and it's all the ""real"" stock. Because remember: a stock exchange is really nothing more than a fancy place for people to buy and sell stocks. There is absolutely no reason why a specific stock should only be traded in one place. Companies that have decided to be publically tradeable generally want to be traded in as many exchanges as possible, because it makes the stock more liquid, which helps their shareholders. Individual exchanges have different requirements for a stock to be listed for trading there, some may even do it without the company's explicit approval." If the share is listed on a stock exchange that creates liquidity and orderly sales with specialist market makers, such as the NYSE, there will always be a counterparty to trade with, though they will let the price rise or fall to meet other open interest.  On other exchanges, or in closely held or private equity scenarios, this is not necessarily the case (NASDAQ has market maker firms that maintain the bid-ask spread and can do the same thing with their own inventory as the specialists, but are not required to by the brokerage rules as the NYSE brokers are).  The NYSE has listing requirements of at least 1.1 million shares, so there will not be a case with only 100 shares on this exchange. In the world of stock exchanges, the result depends on the market state of the traded stock. There are two possibilities, (a) a trade occurs or (b) no trade occurs. During the so-called auction phase, bid and ask prices may overlap, actually they usually do. During an open market, when bid and ask match, trades occur. "It's a scam.  Here are the many signs: The bank will never ask for your password. They can access your account without it.  The bank will never use a customer's account for their own business. They have their own accounts.  ""Some guy"" is not a bank employee. Bank employees are people that you meet at the bank.  Banks do not hand out thousands of dollars for free to customers, especially customers with nothing in their accounts.  Even if you have no money in the account, this crook that you would give access to your account can do lots of illegal things in your name, such as writing bad checks, laundering money, running scams on other people through your account, etc. If you have already given your account info to this person, you need to go to the bank immediately and inform them. Since you have no money in the account, you should close it."