Who puts out buy/sell orders during earnings reports or other scheduled relevant information?
The early bird catches the worm. The first person who makes use of the information gains! That is why hedge funds pay billions of dollars to place their routers right at the center of wall street. Moreover, the information is not always correct. The article you are reading may be a rumor spread by someone on wall street.Then there is speculation and that is factored into the price. For example:- In spite of all the bad news from Greece, the market still continued to rise. This was because, everyone had an idea about what was going to happen and the price was factored in way before Greece actually defaulted. The game is way more complicated than it seems. If everyone sat down and read reports, opportunities to make millions of dollars would have been lost in those few seconds. (Please note:- I do not mean reading reports is bad)
Apparent data-feed issues coming out of NASDAQ in the after hours market. Look at MSFT, AMZN, AAPL, heck even Sears.      Funny thing though, is that you see traces of irregular prices during the active session around 10:20am on stocks like GOOG. You won't be able to know the trading activity in a timely, actionable method in most cases. The exception is if the investor (individual, fund, holding company, non-profit foundation, etc) is a large shareholder of a specific company and therefore required to file their intentions to buy or sell with the SEC. The threshold for this is usually if they own 5% or greater of the outstanding shares. You can, however, get a sense of the holdings for some of the entities you mention with some sleuthing. Publicly-Traded Holding Companies Since you mention Warren Buffett, Berkshire Hathaway is an example of this. Publicly traded companies (that are traded on a US-based exchange) have to file numerous reports with the SEC. Of these, you should review their Annual Report and monitor all filings on the SEC's website. Here's the link to the Berkshire Hathaway profile. Private Foundations Harvard and Yale have private, non-profit foundations. The first place to look would be at the Form 990 filings each is required to file with the IRS. Two sources for these filings are GuideStar.org and the FoundationCenter.org. Keep in mind that if the private foundation is a large enough shareholder in a specific company, they, too, will be required to file their intentions to buy or sell shares in that company. Private Individuals Unless the individual publicly releases their current holdings, the only insight you may get is what they say publicly or have to disclose — again, if they are a major shareholder. 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. No, there is no such list, as the other answers mention it is practically impossible to compile one.  However you can see the institutional investors of a public company.  MSN Money has this information available in a fair amount of details.  For example see the Institutional Investors of GOOG Is there any precedent for companies trading on their own insider information for the benefit of stockholders?  Said another way, if a company were to enter a new market where they were very confident of their ability to steamroll a public competitor, could they use a wholly-owned special-purpose investment vehicle to short that competitor in order to juice the benefit of that move? These sales were not part of their 10b5-1 pre-scheduled trading plans. They occurred after the cyber attack was discovered but before the attack was made public.        I see 3 f-cking idiots going to jail for insider trading.  And say bye-bye too all of the money gained by the options. The NYSE holidays are listed online here: https://www.nyse.com/markets/hours-calendars They mostly make money off of the spread between your order and the spread of the buy and sell currently in the market. As others have previously explained, their buy/sell spreads are a little lacklustre. You need to track every buy and sell to track your gains, or more likely, losses. Yes, you report each and every transactions. Pages of schedule D. according to me it's the news about a particular stock which makes people to buy or sell it mostly thus creates a fluctuation in price . It also dependents on the major stock holder. Thanks for your reply. I’m not familiar with the term “Held-For-Trading Security”. My securities are generally held as collateral against my shorts. To clarify, I am just trying to track the “money in” and “money out” entries in my account for the shorts I write. The transaction is relatively straight forward, except there is a ton of information attached! In simple terms, for the ticker CSR and short contract CSRUQ8, the relevant entries look something like this: There are no entries for expiries. I need to ensure that funds are available for future margin calls and assignments. The sale side using covered calls is as involved. "Changing my answer based on clarification in comments. It appears that some of the securities you mentioned, including GEAPP, are traded on what is colloquially known as the Grey Market. Grey Sheets, and also known as the ""Gray Market"" is another category of OTC stocks that is completely separate from Pink Sheets and the OTCBB.  From investopedia The grey market is an over-the-counter market where dealers may execute orders for preferred customers as well as provide support for a new issue before it is actually issued. This activity allows underwriters and the issuer to determine demand and price the securities accordingly before the IPO.  Some additional information on this type of stocks. (Source) Unlike other financial markets... No recent bid or ask quotes are available because no market makers share data or quote such stocks. There is no quoting system available to record and settle trades. All Grey sheet trading is moderated by a broker and done between consenting individuals at a price they agree on. The only documentation that can be publicly found regarding the trades is when the last trade took place. No SEC registration and little SEC regulation. Regulation of Grey Sheet stocks takes place mainly on a state level. Unlike Pink Sheets, these stocks have no SEC registration to possess a stock symbol or to possess shares or trade shares of that stock. Such penny stocks, similar to Pink Sheets, are not required to file SEC (Securities and Exchange Commission) financial and business reports. These stocks may not be solicited or advertised to the public unless a certain number of shares are qualified to be traded publicly under 504 of Regulation D. Extremely Illiquid. Gray sheet trading is infrequent, and for good reason... Difficult to trade, not advertised, difficult to follow the price, the least regulation possible, hard to find any information on the stock, very small market cap, little history, and most such stocks do not yet offer public shares. The lack of information (bids, history, financial reports) alone causes most investors to be very skeptical of Gray Sheets and avoid them altogether.  Gray Sheets are commonly associated with Initial public offering (IPO) stocks or start up companies or spin-off companies, even though not all are IPO's, start-ups or spin-offs. Grey Sheets is also Home to delisted stocks from other markets. Some stocks on this financial market were once traded on the NASDAQ, OTCBB, or the Pink Sheets but ran into serious misfortune - usually financial - and thus failed to meet the minimum requirements of the registered SEC filings and/or stock exchange regulations for a financial market. Such stocks were delisted or removed and may begin trading on the Grey Sheets.  So to answer your question, I think the cause of the wild swings is that:   Great question, BTW." Just got back from the office, so I can better answer it now. The trader uses the Metatrader platform, which is programmed with a language based off C++. I'm working with him to update some algos now. His strategies running on ToS are more or less proof-of-concept that he streams right now as he sources investors. To dig a little deeper, a number of analysts within (and without) Reuters are polled for their views on individual stocks and markets on buy-hold-sell. The individual analysts will be a varied bunch of fundamentalists, technical, quant and a mixture of the three plus more arcane methodologies. There may be various levels of rumors that aren't strong enough to be considered insider trading, but all of these will give an analyst an impression of the stock/market. Generally I think there isn't much value there, except from the point of view if you are a contrarian trader, then this will form a part of the input to your trading methodology. "http://online.wsj.com/public/resources/documents/goldman0424.pdf ""At the heart of Goldman Sachs‘ sales and trading business is our role as a ―market maker.‖  As a  market maker, the firm stands ready, willing and able to buy and sell financial instruments at the  initiation of our clients.  Goldman Sachs‘ clients expect the firm to do so, regardless of whether  the other side of a transaction has been identified or is readily available. """