How does a stake sale affect a company's stock price?
Is it normal for such transactions to create new outstanding shares? Yes a company can create new shares or a Majority share holder can sell some of his stake or it can be a mix of both. how will this news affect the short-term and long-term price of the company's stock? This is opinion based and not apt for this site. It can be positive or negative depending on how the market reacts to the news.
"What most of these answers here seem to be missing is that a stock ""price"" is not exactly what we typically expect a price to be--for example, when we go in to the supermarket and see that the price of a gallon of milk is $2.00, we know that when we go to the cash register that is exactly how much we will pay.  This is not, however, the case for stocks. For stocks, when most people talk about the price or quote, they are really referring to the last price at which that stock traded--which unlike for a gallon of milk at the supermarket, is no guarantee of what the next stock price will be.  Relatively speaking, most stocks are extremely liquid, so they will react to any information which the ""market"" believes has a bearing on the value of their underlying asset almost (if not) immediately.  As an extreme example, if allegations of accounting fraud for a particular company whose stock is trading at $40 come out mid-session, there will not be a gradual decline in the price ($40 -> $39.99 -> $39.97, etc.)-- instead, the price will jump from $40 to say, $20.  In the time between the the $40 trade and the $20 trade, even though we may say the price of the stock was $40, that quote was actually a terrible estimate of the stock's current (post-fraud announcement) price. Considering that the ""price"" of a stock typically does not remain constant even in the span of a few seconds to a few minutes, it should not be hard to believe that this price will not remain constant over the 17.5 hour period from the previous day's close to the current day's open.  Don't forget that as Americans go to bed, the Asian markets are just opening, and by the time US markets have opened, it is already past 2PM in London.  In addition to the information (and therefore new knowledge) gained from these foreign markets' movements, macro factors can also play an important part in a security's price-- perhaps the ECB makes a morning statement that is interpreted as negative news for the markets or a foreign government before the US markets open.  Stock prices on the NYSE, NASDAQ, etc. won't be able to react until 9:30, but the $40 price of the last trade of a broad market ETF at 4PM yesterday probably isn't looking so hot at 6:30 this morning... don't forget either that most individual stocks are correlated with the movement of the broader market, so even news that is not specific to a given security will in all likelihood still have an impact on that security's price. The above are only a few of many examples of things that can impact a stock's valuation between close and open: all sorts of geopolitical events, announcements from large, multi-national companies, macroeconomic stats such as unemployment rates, etc. announced in foreign countries can all play a role in affecting a security's price overnight. As an aside, one of the answers mentioned after hours trading as a reason--in actuality this typically has very little (if any) impact on the next day's prices and is often referred to as ""amateur hour"", due to the fact that trading during this time typically consists of small-time investors.  Prices in AH are very poor predictors of a stock's price at open." "It is important to first understand that true causation of share price may not relate to historical correlation. Just like with scientific experiments, correlation does not imply causation. But we use stock price correlation to attempt to infer causation, where it is reasonable to do so. And to do that you need to understand that prices change for many reasons; some company specific, some industry specific, some market specific. Companies in the same industry may correlate when that industry goes up or down; companies with the same market may correlate when that market goes up or down. In general, in most industries, it is reasonable to assume that competitor companies have stocks which strongly correlate (positively) with each-other to the extent that they do the same thing.  For a simple example, consider three resource companies: ""Oil Ltd."" [100% of its assets relate to Oil]; ""Oil and Iron Inc."" [50% of its value relates to Oil, 50% to Iron]; and ""Iron and Copper Ltd."" [50% of its value relates to Iron, 50% to Copper]. For each of these companies, there are many things which affect value, but one could naively simplify things by saying ""value of a resource company is defined by the expected future volume of goods mined/drilled * the expected resource price, less all fixed and variable costs"". So, one major thing that impacts resource companies is simply the current & projected price of those resources. This means that if the price of Oil goes up or down, it will partially affect the value of the two Oil companies above - but how much it affects each company will depend on the volume of Oil it drills, and the timeline that it expects to get that Oil. For example, maybe Oil and Iron Ltd. has no currently producing Oil rigs, but it has just made massive investments which expect to drill Oil in 2 years - and the market expects Oil prices to return to a high value in 2 years.  In that case, a drop in Oil would impact Oil Inc. severely, but perhaps it wouldn't impact Oil and Iron Ltd. as much. In this case, for the particular share price movement related to the price of Oil, the two companies would not be correlated. Iron and Copper Ltd. would be unaffected by the price of Oil [this is a simplification; Oil prices impact many areas of the economy], and therefore there would be no correlation at all between this company's shares. It is also likely that competitors face similar markets. If consumer spending goes down, then perhaps the stock of most consumer product companies would go down as well. There would be outliers, because specific companies may still succeed in a falling market, but in generally, there would be a lot of correlation between two companies with the same market.  In the case that you list, Sony vs Samsung, there would be some factors that correlate positively, and some that correlate negatively. A clean example would be Blackberry stock vs Apple stock - because Apple's success had specifically negative ramifications for Blackberry. And yet, other tech company competitors also succeeded in the same time period, meaning they did not correlate negatively with Apple." Can someone please explain how traders and investors use this price difference to trade? People use the price difference for small arbitrage between the futures and spot markets, where the larger spreads are reflected in the options markets. The spread in the options market dictates the VIX which many investors also use in their decision making process.  And most importantly how the futures market affects subsequent moves in the stock market? The futures market effects the stock market where large contract holders move the entire futures price. This causes reactionary moves amongst all of the aforementioned arbitragers, who are hedged between the futures and spot markets. With the /ES this is reflected down to actual individual stocks based on their weightings in the S&P 500 index. Many of those stocks have smaller companies that are also linked to them, such as a widget manufacturer for a gigantic ACME corporation listed in the S&P 500. "It's not necessarily bad but it can cause the stock price to become a lot more volatile. Depends on which side of the bet you're on ;) Suppose a hedge fund manager thinks a company is poorly run. He may buy a ton of shares so that he can get rid of the current CEO and replace it with his/her own. For the hedge fund and others long on the stock, this is good. Those who are trading options or using some short-term strategies could get screwed because of the sudden volatility.  My next point is related to the above. What is the intrinsic value of a stock? The current price of a stock is the equilibrium of all investor's perception of the stock's value. Professionals make up a value for a stock using models such as DCF. Once they do so they trade based on what they believe the value of the stock is. You might calculate a stock is worth 70 and I believe it's 80 so the stock price is going to fluctuate a bit but it should keep within that range (assuming we're the only investors). Then comes a hedge fund manager, say Carl Icahn, and discloses a stake in our stock. ""Wow, the stock must be really valuable!"" Everyone starts buying this stock so up it goes to 90, simply because the guy who seems to know what he's doing bought it. The point here is that now it's not trading based on intrinsic value, now it's purely psychological. Ie. it's now a momentum stock, which you have no idea when it'll crash. Look at Tesla, Netflix, or just google momentum stocks. All the big crashes in stock prices happen when these big funds unload their stocks. A surge in supply will cut the price. The problem is you can't predict when some fund manager will decide to sell some stake of his.  Tying everything together is liquidity. The more liquid a stock is, the easier it is to obtain and the less volatile it is. The more people playing the game, with not too big shares of stock, the faster the price will converge to some equilibrium and with less volatility. Institutional investors take away liquidity." "Generally, a share of stock entitles the owner to all future per-share dividends paid by the company, plus a fraction of the company's assets net value in the event of liquidation.  If one knew in advance the time and value of all such payouts, the value of the stock should equal the present cash value of that payout stream, which would in turn be the sum of the cash values of all the individual payouts. As time goes by, the present cash value of each upcoming payout will increase until such time as it is actually paid, whereupon it will cease to contribute to the stock's value. Because people are not clairvoyant, they generally don't know exactly what future payouts a stock is going to make.  A sane price for a stock, however, may be assigned by estimating the present cash value of its future payments.  If unfolding events would cause a reasonable person to revise estimates of future payments upward, the price of the stock should increase.  If events cause estimates to be revised downward, the price should fall. In a sane marketplace, if the price of a stock is below people's estimates of its payouts' current cash value, people should buy the stock and push the price upward.  If it is above people's estimates, they should sell the stock and push the price downward.  Note that in a sane marketplace, rising prices are a red-flag indicator for people to stop buying.  Unfortunately, sometimes bulls see a red flag as a signal to charge ahead.  When that happens, prices may soar through the roof, but it's important to note that the value of the stock will still be the present cash value of its future payouts.  If that value is $10/share, someone who buys a share for $50 basically gives the seller $40 that he was not entitled to, and which the buyer will never get back.  The buyer might manage to convince someone else to pay him $60 for the share, but that simply means the new buyer is giving the the previous one $50 that he wasn't entitled to either.  If the price falls back to $10, calling that fall a ""market correction"" wouldn't be a euphemism, but rather state a fact: the share was worth $10 before people sold it for crazy prices, and still worth $10 afterward.  It was the market price that was in error. The important thing to focus on as a sane investor is what the stock is actually going to pay out in relation to what you put in.  It's not necessary to look only at present price/earnings ratios, since some stocks may pay little or nothing today but pay handsomely next year.  What's important, however, is that there be a reasonable likelihood that in the foreseeable future the stock will pay dividends sufficient to justify its cost." It has got to do with market perceptions and expectation and the perceived future prospects of the company. Usually the expectation of a company's results are already priced into the share price, so if the results deviate from these expectations, the share price can move up or down respectfully. For example, many times a company's share price may be beaten down for increasing profits by 20% above the previous year when the expectation was that it would increase profits by 30%. Other times a company's share price may rise sharply for making a 20% loss when the expectation was that it would make a 30% loss. Then there is also a company's prospects for future growth and performance. A company may be heading into trouble, so even though they made a $100M profit this year, the outlook for the company may be bleak. This could cause the share price to drop accordingly. Conversely, a company may have made a loss of $100M but its is turning a corner after reducing costs and restructuring. This can be seen as a positive for the future causing the share price to rise. Also, a company making $100M in profits would not put that all into the bank. It may pay dividends with some, it may put some more towards growing the business, and it might keep some cash available in case cash-flows fluctuate during the year. In addition to D. Stanley's very fine answer, the price of stocks change as a result of changing market conditions and the resulting investor estimation of its effect on the company's future earnings. Take these examples. Right now, in the USA, there is a housing shortage; that is, there are fewer houses available for purchase than there are willing buyers. Investors will correctly assume that the future earnings of home builders will be higher than they were, say ten years ago. Seeking to capitalize on these higher earnings, they will try to buy the stocks. However, the current owners of the stock, potentially the sellers, know the same thing as the investor-buyer and therefore demand a premium to entice a sale. The price of the stock has risen. The reverse is true, also. Brick and mortar retailers are declining as more consumers prefer on-line retail shopping. The current owners of these stocks will probably want to sell their stock before it is worth even less. The investor-buyer also knows the same facts; that future earnings will most likely be less for these companies. The potential buyer offers a very low price to entice a sale. The price of the stock has fallen. Finally, the price of stocks rise and fall with general market conditions. As an example, assume that next months jobs report is released showing that 350,000 new jobs were created in July. Investors will believe that if companies are hiring, then the companies are doing well; they are selling products and services at a higher than expected rate, requiring that they add new employees. They will also conclude that those 350,000 new employees will be spending their salaries to buy not just food, clothing and shelter, but also a few luxuries like a newer car, a TV, perhaps even a new home (please see paragraph 2!). All of these companies will have more business, more earnings and, likely, a higher stock price. It seems like you want to compare the company's values not necessarily the stock price.  Why not get the total outstanding shares and the stock price, generate the market cap.  Then you could compare changes to market cap rather than just share price.