How can I remove the movement of the stock market as a whole from the movement in price of an individual share?
As others have pointed out, the value of Apple's stock and the NASDAQ are most likely highly correlated for a number of reasons, not least among them the fact that Apple is part of the NASDAQ. However, because numerous factors affect the entire market, or at least a significant subset of it, it makes sense to develop a strategy to remove all of these factors without resorting to use of an index. Using an index to remove the effect of these factors might be a good idea, but you run the risk of potentially introducing other factors that affect the index, but not Apple. I don't know what those would be, but it's a valid theoretical concern.  In your question, you said you wanted to subtract them from each other, and only see an Apple curve moving around a horizontal line. The basic strategy I plan to use is similar but even simpler. Instead of graphing Apple's stock price, we can plot the difference between its stock price on business day t and business day t-1, which gives us this graph, which is essentially what you're looking for:  While this is only the preliminaries, it should give you a basic idea of one procedure that's used extensively to do just what you're asking. I don't know of a website that will automatically give you such a metric, but you could download the price data and use Excel, Stata, etc. to analyze this.  The reasoning behind this methodology builds heavily on time series econometrics, which for the sake of simplicity I won't go into in great detail, but I'll provide a brief explanation to satisfy the curious. In simple econometrics, most time series are approximated by a mathematical process comprised of several components: In the simplest case, the equations for a time series containing one or more of the above components are of the form that taking the first difference (the procedure I used above) will leave only the random component. However, if you want to pursue this rigorously, you would first perform a set of tests to determine if these components exist and if differencing is the best procedure to remove those that are present. Once you've reduced the series to its random component, you can use that component to examine how the process underlying the stock price has changed over the years. In my example, I highlighted Steve Jobs' death on the chart because it's one factor that may have led to the increased standard deviation/volatility of Apple's stock price. Although charts are somewhat subjective, it appears that the volatility was already increasing before his death, which could reflect other factors or the increasing expectation that he wouldn't be running the company in the near future, for whatever reason. My discussion of time series decomposition and the definitions of various components relies heavily on Walter Ender's text Applied Econometric Time Series. If you're interested, simple mathematical representations and a few relevant graphs are found on pages 1-3. Another related procedure would be to take the logarithm of the quotient of the current day's price and the previous day's price. In Apple's case, doing so yields this graph:  This reduces the overall magnitude of the values and allows you to see potential outliers more clearly. This produces a similar effect to the difference taken above because the log of a quotient is the same as the difference of the logs The significant drop depicted during the year 2000 occurred between September 28th and September 29th, where the stock price dropped from 26.36 to 12.69. Apart from the general environment of the dot-com bubble bursting, I'm not sure why this occurred. Another excellent resource for time series econometrics is James Hamilton's book, Time Series Analysis. It's considered a classic in the field of econometrics, although similar to Enders' book, it's fairly advanced for most investors.  I used Stata to generate the graphs above with data from Yahoo! Finance: There are a couple of nuances in this code related to how I defined the time series and the presence of weekends, but they don't affect the overall concept. For a robust analysis, I would make a few quick tweaks that would make the graphs less appealing without more work, but would allow for more accurate econometrics. The portion of a stock movement not correlated with stocks in general is called Alpha. I don't know of any online tools to graph alpha. Keep in mind that a company like Apple is so huge right now that any properly weighted index will have to correlate with it to some degree. I use StockCharts for spread charting. To take your question as an example, here is the chart of Apple against Nasdaq. You run the regression R_{i,t} = a + bR_{m,t} + e_t, then a + e_t is the variation that isn't shared with the market's variation.
The rest of the market knows when the dividends are paid out, and that will be reflected naturally in the share price. That's why there is no way to consistently beat the market. Because the market is other human beings, who's sum of knowledge is greater than any individual. Everything in the stock market boils down to this in one way or another. Of course, this calculation does not take into consideration the fact that once the rights are issues, the price of the shares will drop. Usually this drop corresponds to the discount. Therefore, if a rights issue is done correctly share price before issuance-discount=share price after issuance. In this result, noone's wealth changes because shareholders can then sell their stock and get back anything they had to put in. "Share prices change (or not) when shares are bought and sold. Unless he's sitting on a large percentage of the total shares, the fact that he isn't selling or buying means he's having no effect ar all on the stock price, and unless there's a vote war going on in the annual meeting his few stockholder votes aren't likely to have much effect there either (though there's always the outside chance of his being a tiebreaker). On the other hand, there's nothing inherently wrong with holding shares for a very long time and just taking the dividends (""clipping coupons""). Buy-and-hold is a legitimate strategy. Basically: His reason is wrong, but his action may be right, and you should probably just not ask." 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. "One of two things is true: You own less than 5% of the total shares outstanding. Your transaction will have little to no effect on the market. For most purposes you can use the current market price to value the position. You own more than 5% of the total shares outstanding. You are probably restricted on when, where, and why you can sell the shares because you are considered part owner of the company. Regardless, how to estimate (not really ""calculate,"" since some of the inputs to the formula are assumptions a.k.a. guesses) the value depends on exactly what you plan to with the result." "One idea: If you came up with a model to calculate a ""fair price range"" for a stock, then any time the market price were to go below the range it could be a buy signal, and above the range it could be a sell signal. There are many ways to do stock valuation using fundamental analysis tools and ratios: dividend discount model, PEG, etc. See Wikipedia - Stock valuation. And while many of the inputs to such a ""fair price range"" calculation might only change once per quarter, market prices and peer/sector statistics move more frequently or at different times and could generate signals to buy/sell the stock even if its own inputs to the calculation remain static over the period. For multinationals that have a lot of assets and income denominated in other currencies, foreign exchange rates provide another set of interesting inputs. I also think it's important to recognize that with fundamental analysis, there will be extended periods when there are no buy signals for a stock, because the stocks of many popular, profitable companies never go ""on sale"", except perhaps during a panic. Moreover, during a bull market and especially during a bubble, there may be very few stocks worth buying. Fundamental analysis is designed to prevent one from overpaying for a stock, so even if there is interesting volume and price movement for the stock, there should still be no signal if that action happens well beyond the stock's fair price. (Otherwise, it isn't fundamental analysis — it's technical analysis.) Whereas technical analysis can, by definition, generate far more signals because it largely ignores the fundamentals, which can make even an overvalued stock's movement interesting enough to generate signals." As stock prices have declined, the net worth of people has come down. Imagine owning a million shares of a stock worth $100/share. This is worth $100,000,000. Now, if the stock is suddenly trading at $50/share then some would say you have lost $50,000,000. The value of the stock is less. The uncertainty is always there as there are differences between one day's close and another day's open possibly. The sale price is likely to be near the last trade is what is being used here. If you place a market order to sell your stock, the price may move between the time the order is placed and when it is filled. There are limit orders that could be used if you want to control the minimum price you get though you give up that the order has to be filled as otherwise people could try to sell shares for millions of dollars that wouldn't work out well. Depending on what currency the price is quoted in and is originally sold, currency fluctuation can also carry over onto the price in your currency. An example for that would be bitcoin prices which sometimes show heavy ups and downs in one currency, but seem totally stable in another and can be tracked back to changed exchange rates between currencies. Also like others have said, prices on stocks are not actually fixed. You can offer to buy or sell at any price. Only if 2 people want to buy or sell for the same price there will actually be a transaction. The volume required to significantly move the price of a security depends completely on the orderbook for that particular security. There are a variety of different reasons and time periods that a security can be halted, this will depend a bit on which exchange you're dealing with. This link might help with the halt aspect of your question: https://en.wikipedia.org/wiki/Trading_halt The risk of the particular share moving up or down is same for both.   however in terms of mitigating the risk, Investor A is conservative on upside, ie will exit if he gets 10%, while is ready to take unlimited downside ... his belief is that things will not go worse .. While Investor B is wants to make at least 10% less than peak value and in general is less risk averse as he will sell his position the moment the price hits 10% less than max [peak value] So it more like how do you mitigate a risk, as to which one is wise depends on your belief and the loss appetite No. The market cap has no relation to actual money that flowed anywhere, it is simple the number of shares multiplied by the current price, and the current price is what potential buyers are (were) willing to pay for the share. So any news that increases or decreases interest in shares changes potentially the share price, and with that the market cap. No money needs to flow. When stocks have a change in price it is because of a TRADE. To have a trade you have to have both a buyer and a seller.  When the price of a security is going up there are an equal amount of shares being sold as being bought. When the price of a security is going down there are an equal amount of shares being bought as being sold.  There almost always is an unequal amount of shares waiting to be sold compared to the amount waiting to be bought. But waiting shares do not move the price, only when the purchase price and the sale price agree, and a trade occurs, does the price move.  So the price does not go down because more shares are being sold. Neither does the price go up because more shares are being bought. I think the simple answer to your question is: Yes, when you sell, that drives down the price. But it's not like you sell, and THEN the price goes down. The price goes down when you sell. You get the lower price.  Others have discussed the mechanics of this, but I think the relevant point for your question is that when you offer shares for sale, buyers now have more choices of where to buy from. If without you, there were 10 people willing to sell for $100 and 10 people willing to buy for $100, then there will be 10 sales at $100. But if you now offer to sell, there are 11 people selling for $100 and 10 people buying for $100. The buyers have a choice, and for a seller to get them to pick him, he has to drop his price a little. In real life, the market is stable when one of those sellers drops his price enough that an 11th buyer decides that he now wants to buy at the lower price, or until one of the other 10 buyers decides that the price has gone too low and he's no longer interested in selling. If the next day you bought the stock back, you are now returning the market to where it was before you sold. Assuming that everything else in the market was unchanged, you would have to pay the same price to buy the stock back that you got when you sold it. Your net profit would be zero. Actually you'd have a loss because you'd have to pay the broker's commission on both transactions. Of course in real life the chances that everything else in the market is unchanged are very small. So if you're a typical small-fry kind of person like me, someone who might be buying and selling a few hundred or a few thousand dollars worth of a company that is worth hundreds of millions, other factors in the market will totally swamp the effect of your little transaction. So when you went to buy back the next day, you might find that the price had gone down, you can buy your shares back for less than you sold them, and pocket the difference. Or the price might have gone up and you take a loss. "Instead of using the actual index, use a mutual fund as a proxy for the index. Mutual funds will include dividend income, and usually report data on the value of a ""hypothetical $10,000 investment"" over the life of the fund. If you take those dollar values and normalize them, you should get what you want. There are so many different factors that feed into general trends that it will be difficult to draw conclusions from this sort of data. Things like news flow, earnings reporting periods, business cycles, geopolitical activity, etc all affect the various sectors of the economy differently." When you buy a stock, you become a partial owner of the company that the stock is for. As the company is valued at a higher or lower amount, the stock will reflect that by gaining or losing value. You still own that stock. For example, if you bought a stock for $10 per share and next week it is worth $8 dollars per share, the only loss incurred is on paper. You do not have to pay the difference (which I think is what you are asking?) and will only physically lose that money if you sell at that point. Similarly if that stock becomes worth $12, you have only gained money on paper and can only physically see it if you sell at that point.