What is the meaning of public stock price data from before the official first day of trading? [duplicate]
For the case of spinoffs it reflects the market as activities as the specific steps that have to be followed take place. For example the spinoff of Leidos from SAIC in 2013. (I picked this one becasue I knew some of the details) On September 9, 2013, the Board of Directors of SAIC, Inc.(Ticker   Symbol (NYSE):SAI) approved the following:  The separation of its technical, engineering and enterprise information technology services business through the distribution of   shares of SAIC  Gemini, Inc. to stockholders.  Each stockholder of   record of SAIC, Inc. as of  September 19, 2013 (Record Date) will   receive one (1) share of SAIC Gemini, Inc. common stock for every   seven (7) shares of SAIC, Inc. common stock  held by such stockholder   as of the Record Date.   This distribution will be effective after   market close on September 27, 2013 (Distribution Date).  After the   Distribution Date, SAIC Gemini, Inc. will be renamed Science   Applications International Corporation (New SAIC). A one (1) for four (4) reverse stock split of the SAIC, Inc. common stock effective as of Distribution Date. After the Distribution Date,   SAIC, Inc. will be renamed Leidos Holdings, Inc. (Leidos). Q 11: What are the different trading markets that may occur between   Record Date and Distribution Date? A: Beginning two days prior to the Record Date of September 19, 2013   through the Distribution Date on September 27, 2013, there may be   three different trading markets available with respect to SAIC, Inc.   and the separation. Stock Ticker – SAI (Regular Way Trading with Due Bills): Shares of SAI common stock that trade on the regular-way market will trade with   an entitlement to shares of the New SAIC common stock distributed on   the Distribution Date.  Purchasers in this market are purchasing both   the shares of Leidos and New SAIC common stock. Form of Stock Ticker –SAIC (When Issued Trading): Shares of New SAIC common stock may be traded on a “when-issued” basis.  These   transactions are made conditionally because the security has been   authorized, but not yet issued.  Purchasers in this market are only   purchasing the shares of  New SAIC common stock distributed on the   Distribution Date. Form of Stock Ticker – LDOS (Ex-Distribution Trading): Shares that trade on the ex-distribution market will trade without an entitlement   to shares of New SAIC common stock distributed on the Distribution   Date.  Purchasers in this market are only purchasing the shares of   Leidos common stock. So the stock price for New SAIC starts a few days before the record date of 19 September 2013, while LDOS (new name for the old SAIC) goes back much earlier. But the company didn't split until after the close of business on 27 September 2013. http://investors.saic.com/sites/saic.investorhq.businesswire.com/files/doc_library/file/GeneralStockholder-QuestionsandAnswers.pdf
"In US public stock markets there is no difference between the actions individual retail traders are ""permitted"" to take and the actions institutional/corporate traders are ""permitted"" to take.  The only difference is the cost of those actions.  For example, if you become a Registered Market Maker on, say, the BATS stock exchange, you'll get some amazing rebates and reduced transaction prices; however, in order to qualify for Registered Market Maker status you have to maintain constant orders in the book for hundreds of equities at significant volumes.  An individual retail trader is certainly permitted to do that, but it's probably too expensive. Algorithmic trading is not the same as automated trading (algorithmic trading can be non-automated, and automated trading can be non-algorithmic), and both can be anywhere from low- to high-frequency.  A low-frequency automated strategy is essentially indistinguishable from a person clicking their mouse several times per day, so: no, from a legal or regulatory perspective there is no special procedure an individual retail trader has to follow before s/he can automate a trading strategy.  (Your broker, on the other hand, may have all sorts of hoops for you to jump through in order to use their automation platform.) Last (but certainly not least) you will almost certainly lose money hand over fist attempting bid-ask scalping as an individual retail trader, whether your approach is algorithmic or not, automated or not.  Why?  Because the only way to succeed at bid-ask scalping is to (a) always be at/near the front of the queue when a price change occurs in your favor, and (b) always cancel your resting orders before they are executed when a price change occurs against you.  Unless your algorithms are smarter than every other algorithm in the industry, an individual retail trader operating through a broker's trading platform cannot react quickly enough to succeed at either of those.  You would have to eschew the broker and buy direct market access to even have a chance, and that's the point at which you're no longer a retail trader. Good luck!" You need a source of delisted historical data. Such data is typically only available from paid sources. According to my records, AULT (Ault Inc) began as an OTC stock in the 1980s prior it having an official NASDAQ listing.  It was delisted on 27 Jan 2006.  Its final traded price was $2.94.  It was taken over at a price of $2.90 per share by SL Industries. Source: Symbol AULT-200601 within Premium Data US delisted stocks historical price data set available from http://www.premiumdata.net/products/premiumdata/ushistorical.php Disclosure: I am a co-owner of Norgate / Premium Data. "From what I have read from O'Neil to Van Tharp, etc, etc, no one can pick winners more than 75% of the time regardless of the system they use and most traders consider themselves successful if 60% of the trades are winners and 40% are losers.  So I am on the side that the chart is only a reflection of the past and cannot tell you reliably what will happen in the future. It is difficult to realize this but here is a simple way for you to realize it. If you look at a daily chart and let's say it is 9:30 am at the open and you ask a person to look at the technical indicators, look at the fundamentals and decide the direction of the market by drawing the graph, just for the next hour. He will realize in just a few seconds that he will say to him or her self ""How on earth do you expect me to be able to do that?""  He will realize very quickly that it is impossible to tell the direction of the market and he realizes it would be foolhardy to even try. Because Mickey Mantle hit over 250 every year of his career for the first 15 years it would be a prudent bet to bet that he could do it again over the span of a season, but you would be a fool to try to  guess if the next pitch would be a ball or a strike. You would be correct about 50% of the time and wrong about 50% of the time. You can rely on LARGER PATTERNS OF BEHAVIOR OVER YEARS, but short hourly or even minute by minute prediction is foolish. That is why to be a trader you have to keep on trading and if you keep on trading and cut your losses to 1/2 of your wins you will eventually have a wonderful profit.  But you have to limit your risk on any one trade to 1% of your portfolio.  In that way you will be able to trade at least 100 times.  do the math.  trade a hundred times.  lose 5% and the next bet gain 10%.  Keep on doing it. You will have losses sometimes of 3 or 4 in a row and also wins sometimes of 3 or 4 in a row but overall if you keep on trading even the best traders are generally only ""right"" 60% of the time.  So lets do the math. If you took 100 dollars and make 100 trades and the first trade you made 10% and reinvested the total and the second trade you lost 5% of that and continue that win/loss sequence for 100 trades you would have 1284 dollars minus commissions. That is a 1200% return in one hundred trades.  If you do it in a roth IRA you pay no taxes on the short term gains.  It is not difficult to realize that the stock market DOES TREND. And the easiest way to make 10% quickly is to in general trade 3x leveraged funds or stocks that have at least 3 beta from the general index.  Take any trend up and count the number of days the stock is up and it is usually 66-75% and take any down trend and it is down 66-75% of the days.  So if you bet on the the beginning of a day when the stock was up and if you buy the next day about 66-75% of the time the stock will also be up. So the idea is to realize that 1/3 of the time at least you will cut your losses but 2/3 of the time you will be up then next day as well.  So keep holding the position based on the low of the previous day and as the stock rises to your trend line then tighten the stock to the low of the same day or just take your profit and buy something else.  But losing 1/3 times is just part of ""the unpredictable"" nature of the stock market which is causes simply because there are three types of traders all betting at the same time on the same stock.  Day traders who are trading from 1 to 10 times a day, swing traders trading from 1 day to several weeks and buy and hold investors holding out for long term capital gains. They each have different price targets and time horizons and THAT DIFFERENCE is what makes the market move.  ONE PERSON'S SHORT TERM EXIT PRICE AT A PROFIT IS ANOTHER PERSONS LONG TERM ENTRY POINT and because so many are playing at the same time with different time horizons, stop losses and exit targets it is impossible to draw the price action or volume.  But it is possible to cut your losses and ride your winners and if you keep on doing that you have a very fine return indeed." "Strategy would be my top factor.  While this may be implied, I do think it helps to have an idea of what is causing the buy and sell signals in speculating as I'd rather follow a strategy than try to figure things out completely from scratch that doesn't quite make sense to me. There are generally a couple of different schools of analysis that may be worth passing along: Fundamental Analysis:Fundamental analysis of a business involves analyzing its financial statements and health, its management and competitive advantages, and its competitors and markets. When applied to futures and forex, it focuses on the overall state of the economy, interest rates, production, earnings, and management. When analyzing a stock, futures contract, or currency using fundamental analysis there are two basic approaches one can use; bottom up analysis and top down analysis. The term is used to distinguish such analysis from other types of investment analysis, such as quantitative analysis and technical analysis. Technical Analysis:In finance, technical analysis is a security analysis methodology for forecasting the direction of prices through the study of past market data, primarily price and volume. Behavioral economics and quantitative analysis use many of the same tools of technical analysis, which, being an aspect of active management, stands in contradiction to much of modern portfolio theory. The efficacy of both technical and fundamental analysis is disputed by the efficient-market hypothesis which states that stock market prices are essentially unpredictable. There are tools like ""Stock Screeners"" that will let you filter based on various criteria to use each analysis in a mix.  There are various strategies one could use.  Wikipedia under Stock Speculator lists: ""Several different types of stock trading strategies or approaches exist including day trading, trend following, market making, scalping (trading), momentum trading, trading the news, and arbitrage.""  Thus, I'd advise research what approach are you wanting to use as the ""Make it up as we go along losing real money all the way"" wouldn't be my suggested approach. There is something to be said for there being numerous columnists and newsletter peddlers if you want other ideas but I would suggest having a strategy before putting one's toe in the water." "Shares sold to private investors are sold using private contracts and do not adhere to the same level of strict regulations as publicly traded shares. You may have different classes of shares in the company with different strings attached to them, depending on the deals made with the investors at the time. Since public cannot negotiate, the IPO prospectus is in fact the investment contract between the company and the public, and the requirements to what the company can put there are much stricter than private sales. Bob may not be able to sell his ""special"" stocks on the public exchange, as the IPO specifies which class of stock is being listed for trading, and Bob's is not the same class. He can sell it on the OTC market, which is less regulated, and then the buyer has to do his due diligence. Yes, OTC-sold stocks may have strings attached to them (for example a buy back option at a preset time and price)." There is no direct relationship between volume and stock price. High volume indicates how much stock is changing hands. That can be because people are enthusiastically buying OR enthusiastically selling... and their reasons for doing so may not agree with your own sense of the future value of the stock. Higher volume may mean that the price is more likely to change during the day, but it can be in either direction -- or in no direction at all if there isn't a general agreement on how to react to some piece of news. It's a possibly interesting datum, but it means nothing in isolation. Various types of corporate actions will precipitate a price adjustment.  In the case of dividends, the cash that will be paid out as a dividend to share holders forms part of a company's equity.  Once the company pays a dividend, that cash is no longer part of the company's equity and the share price is adjusted accordingly. For example, if Apple is trading at $101 per share at the close of business on the day prior to going ex-dividend, and a dividend of $1 per share has been declared, then the closing price will be adjusted by $1 to give a closing quote of $100. Although the dividend is not paid out until the dividend pay date, the share price is adjusted at the close of business on the day prior to the ex-dividend date since any new purchases on or after the ex-dividend date are not entitled to receive the dividend distribution, so in effect new purchases are buying on the basis of a reduced equity.   It will be the exchange providing the quote that performs the price adjustment, not Google or Yahoo.  The exchange will perform the adjustment at the close prior to each ex-dividend date, so when you are looking at historical data you are looking at price data that includes each adjustment. I found the answer. It was the Stock Ticker that I was looking for. So, if I understand correctly the price at certain moment is the price of the latest sale and can be used to get a global picture of what certain stock is worth at that certain instant.