Average Price of a Stock
Edit3: Regarding the usefulness of the bare number itself, it is not useful unless, for example, an employer uses that average in the computation of how many options the employer grants to the employee as part of the compensation paid. One of my employers used just such an average. What is far more common is to use two or more moving averages, of different periods, plotted on a chart.  My original response continues below... Assuming there are 252 trading days a year, the following chart does what you have done but with a moving average: AAPL on Stockcharts.com  Edit: BTW, I looked up the number of Federal holidays, there are 9. The average year has 365.2422 days. 365.2422 × 5/7 = 260.8873. Subtract 9 and you get 251.8873 trading days in the average year. So 252 is a better number for the SMA than 250 if you want to average a year.  Edit2: Here is the same chart with more than one average included: AAPL chart w/indicators That metric is not very useful for anything other than very extremely long trading periods. Most strategies or concerned with price movement over much shorter time frames, 15 mins, 1 hr, 4 hr, daily, weekly, monthly. The MA or moving average is a trend following lagging indicator used to smooth out price fluctuations and more accurately reflect the price of trading instrument such as a stock (AAPL), commodity, or currency pair. Traders are generally concerned with current market trends and price action of the instrument they are trading. As such, an extremely long MA (average daily price, over a period of 365 days) are generally not that important. "I would have to disagree with the other responders. In technical analysis of stock charts, various short and long term moving averages are used to give an indication of the trend of the stock in the short and long term, as compared to the current price. I would prefer to use the term moving average (MA) rather than average as the MA is recalculated every day (or at appropriate frequencies for your data) on the period you are using. I would also expand on the term ""moving average"". There are two that are commonly used Going back to the question, of the value of this number, For example if the current price is above the 200 day EWMA and also above the 30 day EWMA, then the stock is broadly trending upwards. Conversely if current price is below the 200 day EWMA and also below the 30 day EWMA, then the stock is broadly trending downwards. These numbers are chosen on the basis of the market you are trading in, the volatility and other factors. For another example of how a number of moving averages are used together, please have a read of Daryl Guppy's Multiple Moving Average, though this does not use moving averages as large as 200 days."
"So you're basically saying that average market fluctuations have an affect on individual stocks, because individual stocks are often priced in relation to the growth of the market as a whole?  Also, what kinds of investments would be considered ""risk free"" in this nomenclature?" Just guessing here… How about Daily Median price?  StockCharts provides a similar value they call VWAP. Which stands for Volume-Weighted Average Price. I believe it is a better 'average' for the day (click on link). The last column in the source data is volume (the number of stocks that was exchanged during the day), and it also has a value of zero for that day, meaning that nobody bought or sold the stocks on that day. And since the prices are prices of transactions (the first and the last one on a particular day, and the ones with the highest/lowest price), the prices cannot be established, and are irrelevant as there was not a single transaction on that day. Only the close price is assumed equal to its previous day counterpart because this is the most important value serving as a basis to determine the daily price change (and we assume no change in this case). Continuous-line charts also use this single value. Bar and candle charts usually display a blank space for a day where no trade occurred. "Here is how I would approach that problem: 1) Find the average ratios of the competitors: 2) Find the earnings and book value per share of Hawaiian 3) Multiply the EPB and BVPS by the average ratios. Note that you get two very different numbers.  This illustrates why pricing from ratios is inexact.  How you use those answers to estimate a ""price"" is up to you.  You can take the higher of the two, the average, the P/E result since you have more data points, or whatever other method you feel you can justify.   There is no ""right"" answer since no one can accurately predict the future price of any stock." If you believe in the efficient market hypothesis then the stock price reflects the information known to market participants. Consequently, if the 'market' expected earnings to rise, and they did, then the price won't change. Clearly there are circumstances, especially in the short term and for illiquid stocks, where this isn't true, but a lot of work points to this being the case on average. The average price would be $125 which would be used to compute your basis. You paid $12,500 for the stock that is now worth $4,500 which is a loss of $8,000 overall if you sell at this point. It is possible to figure out the next price. Just not for Joe Average. A stock exchange has a orderbook. This has two sides. One side has alle the buyers, how many shares they want, and what they are willing to pay. The other side has all the sellers, how many shares they got, and what price they are willing to accept. If any buyers and sellers match up, their orders are executed, money and shares are exchanged, everyone is happy. So the current asking price (the price you have to pay, to get some shares) is currently 12.46$. Let's say you want 6000 shares, for any price. The orderbook now looks like this: Your order is executed, you get 6000 shares for a total of 74,761$ (5900 * 12,46 + 100 * 12,47$). The order book now looks like this: The new asking price is 12.47$. Congrats, you knew the price in advance. Of course this is simplified, there are millions of entries on both sides, thousands of trades happen every millisecond and you'll have to pay the stock exchange a lot of money to give you all this information in real time.  That's what high frequency traders are doing. They use highly specialised computer systems to exploit differences in stock exchanges all over the world. It's called arbitage. They have to be faster than the other guy. This race has gone on for a few years now, so that the limiting factor starts to become the speed of light. YOU are not going to benefit, or else you would not be asking questions on PERSONAL finance :) I stock is only worth what someone will pay for it.  If you want to sell it you will get market price which is the bid. "The price of the last trade... Is the price of the last trade. It indicates what one particular buyer and seller agreed upon. There is absolutely no requirement that one of them didn't offer too much or demand too little, so this is nearly meaningless as an indication of what anyone else will be willing to offer or demand. An average of trades across a sufficiently large number of transactions might indicate a rough consensus about the value of a stock, but transactions will be clustered around that average and the average itself moves over time. Either you offer to sell or buy at a particular price, wait for that price, and risk the transaction not taking place at all if nobody agrees, or you do a spot transaction and get the best price at that nanosecond (which may not be the best in the next nanosecond). Or you tell the broker what the limits are that you consider acceptable, trading these risks off against each other. Pick the one which comes closest to your intent and ignore the fact that others may be getting a slightly different price. That's just the way the market works. ""If his price is lower, why didn't you buy it there?"" ""He's out of stock."" ""Well, come back when I'm out of stock and I'll be unable to sell it to you for an even better price!""" Graphs are nothing but a representation of data. Every time a trade is made, a point is plotted on the graph. After points are plotted, they are joined in order to represent the data in a graphical format.  Think about it this way.  1.) Walmart shuts at 12 AM. 2.)Walmart is selling almonds at $10 a pound.  3.) Walmart says that the price is going to reduce to $9 effective tomorrow. 4.) You are inside the store buying almonds at 11:59 PM.  5.) Till you make your way up to the counter, it is already 12:01 AM, so the store is technically shut. 6.) However, they allow you to purchase the almonds since you were already in there.  7.) You purchase the almonds at $9 since the day has changed. 8.) So you have made a trade and it will reflect as a point on the graph. 9.) When those points are joined, the curves on the graph will be created. 10.) The data source is Walmart's system as it reflects the sale to you. ( In your case the NYSE exchange records this trade made). Buying a stock is just like buying almonds. There has to be a buyer. There has to be a seller. There has to be a price to which both agree. As soon as all these conditions are met, and the trade is made, it is reflected on the graph. The only difference between the graphs from 9 AM-4 PM, and 4 PM-9 AM is the time. The trade has happened regardless and NYSE(Or any other stock exchange) has recorded it! The graph is just made from that data. Cheers. "This chart concerns an option contract, not a stock. The method of analysis is to assume that the price of an option contract is normally distributed around some mean which is presumably the current price of the underlying asset. As the date of expiration of the contract gets closer the variation around the mean in the possible end price for the contract will decrease. Undoubtedly the publisher has measured typical deviations from the mean as a function of time until expiration from historical data. Based on this data, the program that computes the probability has the following inputs: (1) the mean (current asset price) (2) the time until expiration (3) the expected standard deviation based on (2) With this information the probability distribution that you see is generated (the green hump). This is a ""normal"" or Gaussian distribution. For a normal distribution the probability of a particular event is equal to the area under the curve to the right of the value line (in the example above the value chosen is 122.49). This area can be computed with the formula:  This formula is called the probability density for x, where x is the value (122.49 in the example above). Tau (T) is the reciprocal of the variance (which can be computed from the standard deviation). Mu (μ) is the mean. The main assumption such a calculation makes is that the price of the asset will not change between now and the time of expiration. Obviously that is not true in most cases because the prices of stocks and bonds constantly fluctuate. A secondary assumption is that the distribution of the option price around the mean will a normal (or Gaussian) distribution. This is obviously a crude assumption and common sense would suggest it is not the most accurate distribution. In fact, various studies have shown that the Burr Distribution is actually a more accurate model for the distribution of option contract prices." In my opinion, the average investor should not be buying individual stocks. One reason why is that the average investor is not capable of reading financial statements and evaluating whether a stock is overpriced or underpriced. As such, they're often tempted to make buy/sell decisions based solely on the current value of a stock as compared to the price at which they bought it. The real reasons to buy (or sell) a stock is the expectation of future growth of the company (or continued profit and expected dividends). If you aren't able to analyze a company's financial statements and business plan, then you really aren't in a position to evaluate that company's stock price. So instead of asking whether to sell based on a recent drop in stock price, you should be investigating why the stock price is falling, and deciding whether those reasons indicate a trend that you expect to continue.  If you buy and sell stocks based solely on recent trends in the stock price, you probably will end up buying stocks that have recently risen and selling stocks that have recently fallen. In that case, you are buying high and selling low, which is a recipe for poor financial outcomes. As said previously, most of the time volume does not affect stock prices, except with penny stocks. These stocks typically have a small volume in the 3 or 4 figure range and because of this they typically experience very sharp rises and drops in stock prices, contrasting normal stocks that go up and down constantly every minute. Volume is not one thing you should be looking at when analyzing a stock in most cases, since it is simply the number of people of trades made in a day. That has no effect on the value of the company, whereas looking at P/E ratios, dividend growth, etc all can be analyzed to see if a company is growing and is doing well in its field. If I buy an iPhone, it doesn't matter if 100 other people or 100,000 other people have bought it as well, since they won't really affect my experience with the product. Whereas the type of iPhone I buy will. Lets pretend that TELSA decided to split its stock 10 shares for 1. Now the stock is $35 dollars- would that make you happy?  You dont have any idea how companies are valued.   Berkshire Hathaway Inc. Class A NYSE: BRK.A - Oct 31, 12:58 PM EDT 280,210.00 USD What I do have is this (sample only): Stock X: Average Price of all I purchased before = 80 Total Shares = 200 So if Stock X's price today is 100 how do I know how much my average price will be? Using your sample if you buy 100 new shares and the price is 85 for the purpose of this example your previous total cost is $16,000 ($80 average cost * 200 shares).  With the new example you are adding $8500 to your total cost (100 new shares * $85 example cost per share)  that gives us a total cost of $24,500 and 300 shares. $24,500/300 gives us an average cost of $81.67 per share. As long as you have the average cost and the number of shares you can calculate a new average without knowing what the price was for each transaction. It may still become important to find the price information for tax purposes if you do not sell all of those shares at once and use FIFO for your taxes.