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!
I should have been clearer but my point was that the NYSE seems to be blaming third party vendors for reporting invalid test data but their own website reported the same data so it seems like there might be another issue.   Edit: Found the full comment. It seems that NASDAQ distributed the test data and other parties including the NYSE incorrectly displayed it. I can (barely) understand some third parties incorrectly reporting this data but it seems really bizarre that NYSE wouldn't know how to handle this. &gt; You use Amazon if you use the internet. Amazon AWS controls 50% of the cloud provider market, which provides the back end and holds data for many websites, apps, and services. There's simply no avoiding feeding Amazon since they control the backend  According to your own post, they control only half the backend, which means the other half is controlled by their competitors.  In retail, Amazon controls ~4% of all retail sales in the US, and 40-50% of online sales, which does not look like a monopoly to me.  Yes, they are currently standing out and many investors expect more growth in the future, but this will only be true if they can stay competitive in price/quality/service/etc...  In every area they do business they have well-funded competitors which could start snatching up customers if they slip.  Even AWS, it's not that hard to move to Microsoft's, or some other company's cloud platform if Amazon's rates get too high.  The same is true for Google and Facebook, there's no service they provide that doesn't have well-funded competitors.  Just because they currently lead the market doesn't mean they're a monopoly. I guess it depends on what you mean by 'too big'... IMO, the amount of Data collected aggregated and controlled by Google, FB, MS and Apple... is more than a little concerning.  It's not the size of the company or specifically, how much money they have that causes me worry, or even the fairly obvious monopolistic-like stranglehold they have on their respective markets, but rather the profound influence they have on the USA and indeed the world at large.  Google and facebook can 'paint' trends, create forces in the markets and politics with what equate to simple or minor changes to the way their softwares interact with the us... the population at large. 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...). I will assume that you are not asking in the context of high frequency trading, as this is Personal Finance Stack Exchange. It is completely acceptable to trade odd lots for retail brokerage customers. The odd lot description that you provided in your link, from Interactive Brokers is correct. But even in that context, it says, regarding the acceptability of odd lots to stock exchanges: The exception is that odd lots can be routed to NYSE/ARCA/AMEX, but   only as part of a basket order or as a market-on-close (MOC) order. Google GOOG is traded on the NASDAQ. Everything on the NASDAQ is electronic, and always has been. You will have no problem selling or buying less than 100 shares of Google.  There is also an issue of higher commissions with odd lots: While trading commissions for odd lots may still be higher than for   standard lots on a percentage basis, the popularity of online trading   platforms and the consequent plunge in brokerage commissions means   that it is no longer as difficult or expensive for investors to   dispose of odd lots as it used to be in the past. Notice what it says about online trading making it easier, not more difficult, to trade odd lots. "If you're looking to generate your own charts, you can get up-to-date TSP fund share prices in a Google Docs spreadsheet by ""scraping"" the data from the HTML of certain TSP webpages. You'll need to do this because the GoogleFinance function does not recognize ""private"" funds or collective trusts like those of the TSP. See this thread for tips: Bogleheads • View topic - GoogleFinance price quotes for TSP Funds" Google finance will allow you to import earnings report dates directly to your Google calendar. See screenshot with calendar import button circled in red below. Check the answers to this Stackoverflow question https://stackoverflow.com/questions/754593/source-of-historical-stock-data a number of potential sources are listed