Why do stocks gap up after a buyout is announced?
The price gaps up because the offer is for a price above the current price. Therefore people want to buy now before the price jumps to the offer level. Of course it does depend on the tone of the announcement,  which party is making the announcement, and are they announcing an offer or a deal. If the price is $10, and the offer is for $12; then the price may quickly jump. The early buyers will make the most quick money. They hope that the deal is done quickly, or if not the final price ends up higher.  There are risks. The company could reject the offer. The due diligence could expose a problem. The regulators could reject the deal based on anti-trust issues. The deal could take many months to complete. Or the final deal could be for shares in the new company.  The risks are one reason people sell after the deal/offer is announced. In other cases the seller finally is seeing a profit, or a smaller loss and wants out while they can. "The ""random walk"" that you describe reflects the nature of the information flow about the value of a stock.  If the flow is just little bits of relatively unimportant information (including information about the broader market and the investor pool), you will get small and seemingly random moves, which may look like a meander.  If an important bit of information comes out, like a merger, you will see a large and immediate move, which may not look as random. However, the idea that small moves are a meander of search and discovery and large moves are immediate agreements is incorrect.  Both small moves and large moves are instantaneous agreements about the value of a stock in the form of a demand/supply equilibrium.  As a rule, neither is predictable from the point of view of a single investor, but they are not actually random.  They look different from each other only because of the size of the movement, not because of an underlying difference in how the consensus price is reached."
The stock market is generally a long term investment platform.  The share prices reflect more the companies potential to be profitable in the future rather than its actual value.  Companies that have good potential can over perform their actual value.  We saw this regularly  in the early days of the internet prior to the .com bust.  Companies would go up exponentially based on their idea's and potential.  Investors learned from that and are demanding more these days.  As a result companies that do not show growth potential go down. Companies that show growth and potential (apple and google for 2 easy examples) continue to go up.   Many companies have specific days where employees can buy and sell stocks.  there are minor ripples in the market on these days as the demand and supply are temporarily altered by a large segment of the owner base making trades.  For this reason some companies have a closed pool that is only open to inside trades that then executes the orders over time so that the effect is minimized on the actual stock price.  This is not happening with face book.  Instead many of the investors are dumping their stock directly into the market.  These are savvy investors and if there was potential for profit remaining you would not see the full scale exodus from the stock.  The fact that it is visible is scaring off investors itself.  I can not think of another instance that has gone like facebook, especially one that was called so accurately by many industry pundits. You can, in theory, have the stock price go up without any trading actually occurring. It depends on how the price is quoted. The stock price is not always quoted as the last price someone paid for it. It can also be quoted as the ask price, which is the price a seller is willing to sell at, and the price youd pay if you bought at market. If I am a seller, I can raise the asking price at any time. And if there are no other sellers, or at least none that are selling lower than me, it would look like the price is going up. Because it is, it now costs more to buy it. But no trading has actually occurred. The trades after that date were Ex-DIV, meaning after 5 pm Dec 12, new trades did not include the shares that were to be spun out.  The process is very orderly, no one pays $60 without getting the spinoff, and no one pays $30 but still gets it. The real question is why there's that long delay nearly three weeks to make the spinoff shares available. I don't know.  By the way, the stock options are adjusted as well. Someone owning a $50 put isn't suddenly in the money on 12/13. Edit - (I am not a hoarder. I started a fire last night and realized I had a few Barron's in the paper pile) This is how the ABT quote appeared in the 12/24 issue of Barron's. Both the original quote, and the WI (when issued) for the stock less the spin off company. Should go up because of a company is doing better than the market previously expected it to do, the implication is that it's undervalued at the current price and you buy now you're getting it for less than what it's worth.   If Trump was wrong, then the stock would trade up for a bit before ultimately finishing up where it started when the market realises there's nothing in what he said. I think it's because there are a lot of retail investors in this stock.  They are the ones that tend to overreact on news cycles, so creating bad press or over-hyping bad press really makes the stock price swing. "There's an old adage in the equities business - ""buy on rumor, sell on fact"".  Sometimes the strategy is to buy as soon as the rumor is out about a potential merger and then sell off into the news when it is actually announced, since this is normally when the biggest bounce occurs as part of a merger. The other part of the analysis you should do is to understand which of the companies benefits most (or is hurt the worst) by the merger and then make your play accordingly.  Sometimes the company being acquired will see a bounce while the acquiring firm takes a hit, which is an indication the experts think the acquisition will be a drag on the acquiring company (perhaps because it is taking on a great deal of debt to make the acquisition, or because the acquiring firm is paying too much of a premium for what it's getting in return).  Other times the exact opposite is true, where the company being acquired takes a hit while the buyer bounces, and again, the reasons for this can vary widely. If you wait until the merger is actually announced then by the time you get in, most of the premium from the announcement will likely have already been realized, and you'll be buying near the top of the market for the stock.  The key is to be ahead of the other sellers by seeing the opportunities before they do and then knowing when to get out before everyone else does.  Not an easy thing to pull off when you're trying to anticipate the markets, but it can be done if you do the right research and have patience. Good luck!" It depends on the timing of the events. Sometimes the buying company announces their intention but the other company doesn't like the deal. It can go back and forth several times, before the deal is finalized. The specifics of the deal determine what happens to the stock: The deal will specify when the cutoff is. Some people want the cash, others want the shares.  Some will speculate once the initial offer is announced where the final offer (if there is one) will end up. This can cause a spike in volume, and the price could go up or down. Regarding this particular deal I did find the following: http://www.prnewswire.com/news-releases/expedia-to-acquire-orbitz-worldwide-for-12-per-share-in-cash-300035187.html Additional Information and Where to Find It Orbitz intends to file with the SEC a proxy statement as well as other   relevant documents in connection with the proposed transaction with   Expedia. The definitive proxy statement will be sent or given to the   stockholders of Orbitz and will contain important information about   the proposed transaction and related matters. SECURITY HOLDERS ARE   URGED TO READ THE PROXY STATEMENT CAREFULLY WHEN IT BECOMES AVAILABLE   AND ANY OTHER RELEVANT DOCUMENTS FILED WITH THE SEC, AS WELL AS ANY   AMENDMENTS OR SUPPLEMENTS TO THOSE DOCUMENTS, BECAUSE THEY WILL   CONTAIN IMPORTANT INFORMATION. The proxy statement and other relevant   materials (when they become available), and any other documents filed   by Expedia or Orbitz with the SEC, may be obtained free of charge at   the SEC's website, at www.sec.gov. In addition, security holders will   be able to obtain free copies of the proxy statement from Orbitz by   contacting Investor Relations by mail at ATTN: Corporate Secretary,   Orbitz Worldwide, Inc., 500 W. Madison Street, Suite 1000, Chicago,   Illinois 60661. "As others have pointed out, there are often many factors that are contributing to a stock's movement other than the latest news.  In particular, the overall market sentiment and price movement very often is the primary driver in any stock's change on a given day.   But in this case, I'd say your anecdotal observation is correct: All else equal, announcements of layoffs tend to drive stock prices upwards. Here's why: To the public, layoffs are almost always a sign that a company is willing to do whatever is needed to fix an already known and serious problem. Mass layoffs are brutally hard decisions.  Even at companies that go through cycles of them pretty regularly, they're still painful every time.  There's a strong personal drain on the chain of executives that has to decide who loses their livelihood.  And even if you think most execs don't care (and I think you'd be wrong) it's still incredibly distracting.   The process takes many weeks, during which productivity plummets. And it's demoralizing to everyone when it happens. So companies very rarely do it until they think they have to.  By that point, they are likely struggling with some very publicly known problems - usually contracting (or negative) margins.   So, the market's view of the company at the time just before layoffs occur is almost always, ""this company has problems, but is unable or unwilling to solve them."".  Layoffs signal that both of those possibilities are incorrect.  They suggest that the company believes that layoffs will fix the problem, and that they're willing to make hard calls to do so. And that's why they usually drive prices up." Usually when a stock is up-trending or down-trending the price does not go up or down in a straight line. In an uptrend the price may go up over a couple of days then it could go down the next day or two, but the general direction would be up over the medium term. The opposite for a downtrend. So if the stock has been generally going up over the last few weeks, it may take a breather for a week or two before prices continue up again. This breather is called a retracement in the uptrend. The Fibonacci levels are possible amounts by which the price might retract before it continues on its way up again. By the way 50% is not actually a Fibonacci Retracement level but it is a common retracement level which is usually used in combination with the Fibonacci Retracement levels. It might be clearer to think of it as price going up when a dividend is expected, since that's money you'll get right back. As the delay before the next dividend payment increases, that becomes less of a factor, 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. You might be right about that, but your previous posts don't say that.  In just the last one you said:  &gt;Because buyback decreases shares outstanding it **also decreases the company's total future dividend payouts as well**  This is indicating that you believe there is a difference somehow, no? A stock's price does not move in a completely continuous fashion.  It moves in discrete steps depending on who is buying/selling at given prices. I'm guessing that by opening bell the price for buying/selling a particular stock has changed based on information obtained overnight. A company's stock closes at $40.  Overnight, news breaks that the company's top selling product has a massive defect.  The next morning the market opens.  Are there any buyers of the stock at $40?  Probably not.  The first trade of the stock takes place at $30 and is thus, not the same as the previous day's close. "The simple answer could be that one or more ""people"" decided to buy. By ""people,"" I don't mean individual buyers of 100 shares like you or me, but typically large institutional investors like Fidelity, who might buy millions of shares at a time. Or if you're talking about a human person, perhaps someone like Warren Buffett. In a ""thinly"" traded small cap stock that typically trades a few hundred shares in a day, an order for ""thousands"" could significantly move the price. This is one situation where more or less ""average"" people could move a single stock." The other answer has some good points, to which I'll add this:  I believe you're only considering a company's Initial Public Offering (IPO), when shares are first offered to the public.  An IPO is the way most companies get a public listing on the stock market. However, companies often go to market again and again to issue/sell more shares, after their IPO.  These secondary offerings don't make as many headlines as an IPO, but they are typical-enough occurrences in markets. When a company goes back to the market to raise additional funds (perhaps to fund expansion), the value of the company's existing shares that are being traded is a good indicator of what they may expect to get for a secondary offering of shares. A company about to raise money desires a higher share price, because that will permit them to issue less shares for the amount of money they need.  If the share price drops, they would need to issue more shares for the same amount of money – and dilute existing owners' share of the overall equity further. Also, consider corporate acquisitions:  When one company wants to buy another, instead of the transaction being entirely in cash (maybe they don't have that much in the bank!), there's often an equity component, which involves swapping shares of the company being acquired for new shares in the acquiring company or merged company.  In that case, the values of the shares in the public marketplace also matter, to provide relative valuations for the companies, etc.