Why do some services list an IPO date that is well after historical price data you can find elsewhere?
"The Minnesota Mining and Manufacturing Company was established in 1902 as a private company.  It first raised public funds around 1903 but had a limited shareholder base.  By around 1929, it was reported as being tradeable as an OTC (over-the-counter) stock but it's likely that shares were traded well before this.  On 14 Jan 1946, the stock was listed on NYSE.  On 26 Sep 1962 it became a constituent of the the S&P 500 index.  On 9 Aug 1976 it became a constituent of the Dow Jones Industrial Average. In 2002, the company's name changed to 3M Co. It appears that the data on Crunchbase's ""IPO Date"" is wrong on this one. However, there are several companies that appear to do an ""IPO"" and have trading prices prior.  This is quite typical of early-stage biotech companies that trade OTC prior to a major exchange listing and ""IPO"". An example of an IPO happening after a company became publicly tradeable is NASDAQ:IMRN (Immuron). They had an ""IPO"" on Nasdaq on 9 Jun 2017, yet they had been trading as an OTC/Pink Sheet stock for months prior. They also have been listed in Australia since 30 Apr 1999. http://www.nasdaq.com/markets/ipos/activity.aspx?tab=pricings&month=2017-06 Another example is NASDAQ:GNTY (Guaranty Banchshares Inc) which had an ""IPO"" and NASDAQ listing in May 2017. This was a Nasdaq stock in 1998, went OTC/pink sheet stock in 2005. It has been paying regular dividends since that time. Clearly the word ""Initial"" is subjective!  http://www.nasdaq.com/markets/ipos/activity.aspx?tab=pricings&month=2017-05"
Stock prices reflect future expectations of large groups of people, and may not be directly linked to traditional valuations for a number of reasons (not definitive). For example, a service like Twitter is so popular that even though it has no significant revenue and loses money, people are simply betting that it is deeply embedded enough that it will eventually find some way to make money. You can also see a number of cases of IPOs of various types of companies that do not even have a revenue model at all. Also, if there is rapid sales growth in A but B sales are flat, no one is likely to expect future profit growth in B such that the valuation will remain steady. If sales in A are accelerating, there may be anticipation that future profits will be high. Sometimes there are also other reasons, such as if A owns valuable proprietary assets, that will hold the values up. However, more information about these companies' financials is really needed in order to understand why this would be the case. "Try the general stock exchange web page. http://www.aex.nl I did a quick trial myself and was able to download historical data for the AEX index for the last few years.  To get to the data, I went to the menu point ""Koersen"" on the main page and chose ""Indices"". I then entered into the sub page for the AEX index. There is a price chart window in which you have to choose the tab ""view data"". Now you can choose the date range you need and then download in a table format such as excel or csv. This should be easy to import into any software.  This is the direct link to the sub page: http://www.aex.nl/nl/products/indices/NL0000000107-XAMS/quotes" Technically, of course. Almost any company can go bankrupt. One small note: a company goes bankrupt, not its stock. Its stock may become worthless in bankruptcy, but a stock disappearing or being delisted doesn't necessarily mean the company went bankrupt. Bankruptcy has implications for a company's debt as well, so it applies to more than just its stock. I don't know of any historical instances where this has happened, but presumably, the warning signs of bankruptcy would be evident enough that a few things could happen.  Another company, e.g. another exchange, holding firm, etc. could buy out the exchange that's facing financial difficulty, and the companies traded on it would transfer to the new company that's formed. If another exchange bought out the struggling exchange, the shares of the latter could transfer to the former. This is an attractive option because exchanges possess a great deal of infrastructure already in place. Depending on the country, this could face regulatory scrutiny however. Other firms or governments could bail out the exchange if no one presented a buyout offer. The likelihood of this occurring depends on several factors, e.g. political will, the government(s) in question, etc. For a smaller exchange, the exchange could close all open positions at a set price. This is exactly what happened with the Hong Kong Mercantile Exchange (HKMex) that MSalters mentioned. When the exchange collapsed in May 2013, it closed all open positions for their price on the Thursday before the shutdown date. I don't know if a stock exchange would simply close all open positions at a set price, since equity technically exists in perpetuity regardless of the shutdown of an exchange, while many derivatives have an expiration date. Furthermore, this might not be a feasible option for a large exchange. For example, the Chicago Mercantile Exchange lists thousands of products and manages hundreds of millions of transactions, so closing all open positions could be a significant undertaking.  If none of the above options were available, I presume companies listed on the exchange would actively move to other, more financially stable exchanges. These companies wouldn't simply go bankrupt. Contracts can always be listed on other exchanges as well. Considering the high level of mergers and acquisitions, both unsuccessful and successful,  in the market for exchanges in recent years, I would assume that option 1 would be the most likely (see the NYSE Euronext/Deutsche Börse merger talks and the NYSE Euronext/ICE merger that's currently in progress), but for smaller exchanges, there is the recent historical precedent of the HKMex that speaks to #3. Also, the above answer really only applies to publicly traded stock exchanges, and not all stock exchanges are publicly-held entities. For example, the Shanghai Stock Exchange is a quasi-governmental organization, so I presume option 2 would apply because it already receives government backing. Its bankruptcy would mean something occurred for the government to withdraw its backing or that it became public, and a discussion of those events occurring in the future is pure speculation. "Usually... I think that's overstating the case.  You CAN get a bargain (especially if the place is in not-so-great condition), but not every foreclosure will be a good deal even if it is priced well below its most recently appraised value. As the buyer it's your responsibility to determine whether it's priced well or not, and to decide whether you're willing and able to repair its deficiencies after you buy it. The same's true when purchasing any house; foreclosures just make it more likely that there are problems and (hopefully) wind up being priced to allow for them. I don't know of a single website which lists all foreclosures. Some of the home listing websites do have a ""show me foreclosure listings"" filter, and I'm sure that the better tools available to real estate agents can select these. But if that's the direction you're interested in going, you should be looking at distressed properties generally, NOT just foreclosures; you may get a better deal, in the long run, by going for the one that has been mechanically maintained but is just plain ugly rather than the one with a pretty skin whose heating system hasn't been serviced for the last decade. Do your homework, shop around, don't fall in love with any one house... all the same rules apply at this end of the spectrum just as strongly as they do in the mid or upper ranges. Perhaps more so. Happy hunting!" There are lots of things that can be graphed apart from financial data. Like flight data, for example. With the level of detail visible in the pics on that site, what reason is there to conclude that's market data? Interesting theory tho. It's a drive by swipe at technicals, which is fine and all, but I always thought technicals effectively provide odds of an event happening. For example, $XYZ price is a support level, therefore there are increased odds it will bounce higher from these levels, rather than an implied *guarantee* the support will hold. "Remember that in most news outlets journalists do not get to pick the titles of their articles.  That's up to the editor.  So even though the article was primarily about ETFs, the reporter made the mistake of including some tangential references to mutual funds.  The editor then saw that the article talked about ETFs and mutual funds and -- knowing even less about the subject matter than the reporter, but recognizing that more readers' eyeballs would be attracted to a headline about mutual funds than to a headline about ETFs -- went with the ""shocking"" headline about the former. In any case, as you already pointed out, ETFs need to know their value throughout the day, as do the investors in that ETF.  Even momentary outages of price sources can be disastrous. Although mutual funds do not generally make transactions throughout the day, and fund investors are not typically interested in the fund's NAV more than once per day, the fund managers don't just sit around all day doing nothing and then press a couple buttons before the market closes.  They do watch their NAV very closely during the day and think very carefully about which buttons to press at the end of the day.  If their source of stock price data goes offline, then they're impacted almost as severely as -- if less visibly than -- an ETF. Asking Yahoo for prices seems straightforward, but (1) you get what you pay for, and (2) these fund companies are built on massive automated infrastructures that expect to receive their data from a certain source in a certain way at a certain time.  (And they pay a lot of money in order to be able to expect that.)  It would be quite difficult to just feed in manual data, although in the end I suspect some of these companies did just that.  Either they fell back to a secondary data supplier, or they manually constructed datasets for their programs to consume." Besides overnight news events and auction mechanisms there is a more fundamental reason the price of a stock is always moving.  Theoretically the stock price will move slightly even in the unlikely scenario that absolutely nothing of interest happens during the entire night.  Let me go into that in some more detail: Stock valuation using Discounted Cash FLow One of the fundamental reasons that stock value is constantly changing is because underneath every stock there is a company that expects to make some kind of profit or loss in the future. We have to go into the fundamentals of stock value to understand why this is important: One popular way to determine the value of a stock is by looking into the future and summing up all the earnings (or cashflows) it has yet to produce. You have to reduce each amount by a certain factor that gets larger for payments that are farther into the future. Think of it this way: a dollar in hand now is better than a dollar that you get tomorrow. This method of valuation is called Discounted Cash Flow (abbr. DCF; see the wikipedia article on DCF) Time's effect on stock value Now take the Close price C, and the open price O. Let's assume that since there has been no news, the expectations for future earnings are the same for C and O. Remember that the discounting factor for these earnings is dependent on the time until the cashflow occurs? For O, this time is slightly shorter than for C, and therefore the value will be slightly higher (or lower, when the company is expected to incur losses). So now you can see that even without all the external forces that continuously push and pull on the stock price, a stock still changes in value over time. Hope this helps.