How websites like Google have access to stock market data?
"At the bottom of Yahoo! Finance's S & P 500 quote Quotes are real-time for NASDAQ, NYSE, and NYSE MKT. See also delay   times for other exchanges. All information provided ""as is"" for   informational purposes only, not intended for trading purposes or   advice. Neither Yahoo! nor any of independent providers is liable for   any informational errors, incompleteness, or delays, or for any   actions taken in reliance on information contained herein. By   accessing the Yahoo! site, you agree not to redistribute the   information found therein. Fundamental company data provided by Capital IQ. Historical chart data   and daily updates provided by Commodity Systems, Inc. (CSI).   International historical chart data, daily updates, fund summary, fund   performance, dividend data and Morningstar Index data provided by   Morningstar, Inc. Orderbook quotes are provided by BATS Exchange. US   Financials data provided by Edgar Online and all other Financials   provided by Capital IQ. International historical chart data, daily   updates, fundAnalyst estimates data provided by Thomson Financial   Network. All data povided by Thomson Financial Network is based solely   upon research information provided by third party analysts. Yahoo! has   not reviewed, and in no way endorses the validity of such data. Yahoo!   and ThomsonFN shall not be liable for any actions taken in reliance   thereon. Thus, yes there is a DB being accessed that there is likely an agreement between Yahoo! and the providers." To quote their disclaimer: Data is provided by financial exchanges and may be delayed as specified by financial exchanges or our data providers. Google does not verify any data and disclaims any obligation to do so. That means that they buy it from a reseller such as IDC. It probably differs in source between the different exchanges depending on price and availability factors. They do specify in some cases which reseller they use and one of those happens to be Interactive Data (IDC) who are also the data provider used in my day job!
In order to see whether you can buy or sell some given quantity of a stock at the current bid price, you need a counterparty (a buyer) who is willing to buy the number of stocks you are wishing to offload. To see whether such a counterparty exists, you can look at the stock's order book, or level two feed. The order book shows all the people who have placed buy or sell orders, the price they are willing to pay, and the quantity they demand at that price. Here is the order book from earlier this morning for the British pharmaceutical company, GlaxoSmithKline PLC.  Let's start by looking at the left-hand blue part of the book, beneath the yellow strip. This is called the Buy side. The book is sorted with the highest price at the top, because this is the best price that a seller can presently obtain. If several buyers bid at the same price, then the oldest entry on the book takes precedence. You can see we have five buyers each willing to pay 1543.0 p (that's 1543 British pence, or £15.43) per share. Therefore the current bid price for this instrument is 1543.0. The first buyer wants 175 shares, the next, 300, and so on. The total volume that is demanded at 1543.0p is 2435 shares. This information is summarized on the yellow strip: 5 buyers, total volume of 2435, at 1543.0. These are all buyers who want to buy right now and the exchange will make the trade happen immediately if you put in a sell order for 1543.0 p or less. If you want to sell 2435 shares or fewer, you are good to go. The important thing to note is that once you sell these bidders a total of 2435 shares, then their orders are fulfilled and they will be removed from the order book. At this point, the next bidder is promoted up the book; but his price is 1542.5, 0.5 p lower than before. Absent any further changes to the order book, the bid price will decrease to 1542.5 p. This makes sense because you are selling a lot of shares so you'd expect the market price to be depressed. This information will be disseminated to the level one feed and the level one graph of the stock price will be updated. Thus if you have more than 2435 shares to sell, you cannot expect to execute your order at the bid price in one go. Of course, the more shares you are trying to get rid of, the further down the buy side you will have to go. In reality for a highly liquid stock as this, the order book receives many amendments per second and it is unlikely that your trade would make much difference. On the right hand side of the display you can see the recent trades: these are the times the trades were done (or notified to the exchange), the price of the trade, the volume and the trade type (AT means automatic trade).  GlaxoSmithKline is a highly liquid stock with many willing buyers and sellers. But some stocks are less liquid. In order to enable traders to find a counterparty at short notice, exchanges often require less liquid stocks to have market makers. A market maker places buy and sell orders simultaneously, with a spread between the two prices so that they can profit from each transaction. For instance Diurnal Group PLC has had no trades today and no quotes. It has a more complicated order book, enabling both ordinary buyers and sellers to list if they wish, but market makers are separated out at the top. Here you can see that three market makers are providing liquidity on this stock, Peel Hunt (PEEL), Numis (NUMS) and Winterflood (WINS). They have a very unpalatable spread of over 5% between their bid and offer prices. Further in each case the sum total that they are willing to trade is 3000 shares. If you have more than three thousand Dirunal Group shares to sell, you would have to wait for the market makers to come back with a new quote after you'd sold the first 3000. Trading data can be had cheaply from:  http://eoddata.com/products/historicaldata.aspx  The SEC will give you machine readable financial statements for American companies for free, but that only goes back 3 or 4 years.  Beyond that, you will have to pay for a rather expensive service like CapitalIQ or CRSP or whatever.  Note that you will need considerable programming knowledge to pull this off. "A ""stock price"" is nothing but the price at which some shares of that stock were sold on an exchange from someone willing to sell those shares at that price (or more) to someone willing to buy them at that price (or less). Pretty much every question about how stock prices work is answered by the paragraph above, which an astonishingly large number of people don't seem to be aware of. So there is no explicit ""tracking"" mechanism at all. Just people buying and selling, and if the current going price on two exchanges differ, then that is an opportunity for someone to make money by buying on one exchange and selling on the other - until the prices are close enough that the fees and overhead make that activity unprofitable. This is called ""arbitrage"" and a common activity of investment banks or (more recently) hedge funds and specialized trading firms spun off by said banks due to regulation." Companies release their earnings reports over news agencies like Reuters, Dow Jones and Bloomberg before putting them on their website (which usually occurs a few minutes after the official dissemination of the report). This is because they have to make sure that all investors get the news at the same time (which is kind of guaranteed when official news channels are used). The conference call is usually a few hours after the earnings report release to discuss the results with analysts and investors. You seem to be confused - try answering these:  1. Whom do the traders work for?  2. What are the traders trading and how do they acquire those vehicles?  3. How does a company make money and how does that money get deployed?  Google will be crucial for these, but will answer your questions. If you choose to get in finance, remember the golden rule: if you have a question, Google it first. Take a look at this: http://code.google.com/p/stock-portfolio-manager/ It is an open source project aimed to manage your stock portfolio. You can buy the data and process it on your own.  http://www.nyxdata.com/Data-Products/Daily-TAQ Try Google Finance Screener ; you will be able to filter for NASDAQ and NYSE exchanges. You may refer to project http://jstock.sourceforge.net. It is open source and released under GPL. It is fetching data from Yahoo! Finance, include delayed current price and historical price. I dont know if this data is available for the 1980s, but this response to an old question of mine discusses how you can pull stock related information from google or yahoo finance over a certain period of time. You could do this in excel or google spreadsheet and see if you could get the data you're looking for.  Quote from old post: Google Docs spreadsheets have a   function for filling in stock and fund   prices. You can use that data to graph (fund1   / fund2) over some time period. Generally Google gets their data,  directly from the exchanges (Nasdaq, NYSE). This is really expensive   -- tens of thousands of dollars a month just for the license from the exchange, and lots of telecom costs on top of that. It depends on what site you're looking on and what exchange they're pulling the data from. Even though funds and stocks are called the same thing, they have different ticker symbols in each country's exchange or could be traded as pink sheet stocks in the US. If a company or fund is based in another country (like Canada or the UK) they probably also trade on that country's exchange (Toronto or London) under a different symbol. This can cause a lot of confusion when researching these tickers. For whatever reason, I don't believe they offer it.  Yahoo does.  A google for google finance VIX turns up people asking the question, but no quote on google. "NASDAQ OMX Group owns NASDAQ, a stock exchange. It is a corporation, and is listed on the NASDAQ as NDAQ. It makes money by: source NASDAQ also charges for market data services, found in the NASDAQ ""Datastore"". Other information about the fees charged by NYSE and NASDAQ may be found in the Investopedia article The NYSE And Nasdaq: How They Work." You can get this data from a variety of sources, but likely not all from 1 source.  Yahoo is a good source, as is Google, but some stock markets also give away some of this data, and there's foreign websites which provide data for foreign exchanges.    Some Googling is required, as is knowledge of web scraping (R, Python, Ruby or Perl are great tools for this...).