Is there a mathematical formula to determine a stock's price at a given time?
A stock market is just that, a market place where buyers and sellers come together to buy and sell shares in companies listed on that stock market. There is no global stock price, the price relates to the last price a stock was traded at on a particular stock market. However, a company can be listed on more than one stock exchange. For example, some Australian companies are listed both on the Australian Stock Exchange (ASX) and the NYSE, and they usually trade at different prices on the different exchanges. Also, there is no formula to determine a stock price. In your example where C wants to buy at 110 and B wants to sell at 120, there will be no sale until one or both of them decides to change their bid or offer to match the opposite, or until new buyers and/or sellers come into the market closing the gap between the buy and sell prices and creating more liquidity. It is all to do with supply and demand and peoples' emotions. "The fallacy in your question is in this statement: ""The formulas must exist, because prices can be followed real time."" What you see are snapshots of the current status of the stock, what was the last price a stock was traded at, what is the volume, is the price going up or down.  People who buy and hold their stock look at the status every few days or even every few months. Day traders look at the status every second of the trading day.  The math/formula comes in when people try to predict where the stock is going based on the squiggles in the line. These squiggles move based on how other people react to the squiggles.  The big movements occur when big pieces of news make large movements in the price. Company X announces the release of the key product will be delayed by a year; the founder is stepping down; the government just doubled the order for a new weapon system; the insiders are selling all the shares they can. There are no formulas to determine the correct price, only formulas that try to predict where the price may go." I found the answer. It was the Stock Ticker that I was looking for. So, if I understand correctly the price at certain moment is the price of the latest sale and can be used to get a global picture of what certain stock is worth at that certain instant. Try to find the P/E ratio of the Company and then Multiply it with last E.P.S, this calculation gives the Fundamental Value of the share, anything higher than this Value is not acceptable and Vice versa.
"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." The worth of a share of stocks may be defined as the present cash value of all future dividends and liquidations associated therewith.  Without a crystal ball, such worth may generally only be determined retrospectively, but even though it's generally not possible to know the precise worth of a stock in time for such information to be useful, it has a level of worth which is absolute and not--unlikely market price--is generally unaffected by people buying and selling the stock (except insofar as activities in company stock affect a company's ability to do business). If a particular share of stock is worth $10 by the above measure, but Joe sells it to Larry for $8, that means Joe gives Larry $2.  If Larry sells it to Fred $12, Fred gives Larry $2.  The only way Fred can come out ahead is if he finds someone else to give him $2 or more.  If Fred can sell it to Adam for $13, then Adam will give Fred $3, leaving Fred $1 better off than he would be if he hadn't bought the stock, but Adam will be $3 worse off. The key point is that if you sell something for less than it's worth, or buy something for more that it's worth, you give money away.  You might be able to convince other people to give you money in the same way you gave someone else money, but fundamentally the money has been given away, and it's not coming back. "To know if a stock is undervalued is not something that can be easily assessed (else, everybody would know which stock is undervalued and everybody will buy it until it reaches its ""true"" value). But there are methods to assess the value of a company, I think that the 3 most known methods are: If the assets of the company were to be sold right now and that all its   debts were to be paid back right now, how much will be left? This   remaining amount would be the fundamental value of your company. That method could work well on real estate company whose value is more or less the buildings that they own minus of much they borrowed to acquire them. It's not really usefull in the case of Facebook, as most of its business is immaterial. I know the value of several companies of the same sector, so if I want   to assess the value of another company of this sector I just have to   compare it to the others. For example, you find out that simiral internet companies are being traded at a price that is 15 times their projected dividends (its called a Price Earning Ratio). Then, if you see that Facebook, all else being equal, is trading at 10 times its projected dividends, you could say that buying it would be at a discount. A company is worth as much as the cash flow that it will give me in   the future If you think that facebook will give some dividends for a certain period of time, then you compute their present value (this means finding how much you should put in a bank account today to have the same amount in the future, this can be done by dividing the amount by some interest rates). So, if you think that holding a share of a Facebook for a long period of time would give you (at present value) 100 and that the share of the Facebook is being traded at 70, then buy it. There is another well known method, a more quantitative one, this is the Capital Asset Pricing Model. I won't go into the details of this one, but its about looking at how a company should be priced relatively to a benchmark of other companies. Also there are a lot's of factor that could affect the price of a company and make it strays away from its fundamental value: crisis, interest rates, regulation, price of oil, bad management, ..... And even by applying the previous methods, the fundemantal value itself will remain speculative and you can never be sure of it. And saying that you are buying at a discount will remain an opinion. After that, to price companies, you are likely to understand financial analysis, corporate finance and a bit of macroeconomy." Really not sure with this one and I don't want to cheat and look up an answer.  I'd say you could find the high/low points of the stock over the last year or two and see how large the spread is between those values and the average price of the stock over the same time period. "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." "At any given moment, one can tally the numbers used for NAV. It's math, and little more. The Market Cap, which as you understand is a result of share value. Share value (stock price) is what the market will pay today for the shares. It's not only based on NAV today, but on future expectations. And expectations aren't the same for each of us. Which is why there are always sellers for the buyers of a stock, and vice-versa.  From your question, we agree that NAV can be measured, it's the result of adding up things that are all known. (For now, let's ignore things such as ""goodwill."") Rarely is a stock price simply equal to the NAV divided by the number of shares. Often, it's quite higher. The simplest way to look at it is that the stock price not only reflects the NAV, but investors' expectations looking into the future.  If you look for two companies with identical NAV per share but quite different share prices, you'll see that the companies differ in that one might be a high growth company, the other, a solid one but with a market that's not in such a growth mode." "My Broker and probably many Brokers provide this information in a table format under ""Course of Sale"". It provides the time, price and volume of each trade on that day. You could also view this data on a chart in some charting programs. Just set the interval to ""Tick by Tick"" and look at the volume. ""Tick by Tick"" will basically place a mark for every trade that is taken and then the volume will tell you the size of that trade." There is no formula for calculating a stock price based on the financials of a company. A stock price is set by the market and always has a component built into it that is based on something outside of the current valuation of a company using its financials. Essentially, the stock price of a company per share is whatever the best price it can get on the open market. If you are looking at how to evaluate if a stock is a good value at the current price, then look at some of the answers, but I wanted to answer this based on the way you phrased the question. How can you correlate a company stock's performance with overall market performance. No you can't. There is no simple magic formulae that will result in profits. There are quite a few statistical algorithms that specialists have built, that work most of the times. But they are incorrect most of the times as well. "What you are seeking is termed ""Alpha"", the mispricing in the market. Specifically, Alpha is the price error when compared to the market return and beta of the stock. Modern portfolio theory suggests that a portfolio with good Alpha will maximize profits for a given risk tolerance. The efficient market hypotheses suggests that Alpha is always zero. The EMH also suggests that taxes, human effort and information propagation delays don't exist (i.e. it is wrong). For someone who is right, the best specific answer to your question is presented Ben Graham's book ""The Intelligent Investor"" (starting on page 280). And even still, that book is better summarized by Warren Buffet (see Berkshire Hathaway Letters to Shareholders). In a great disservice to the geniuses above it can be summarized much further: closely follow the company to estimate its true earnings potential... and ignore the prices the market is quoting. ADDENDUM: And when you have earnings potential, calculate value with: NPV = sum(each income piece/(1+cost of capital)^time) Update: See http://finance.fortune.cnn.com/2014/02/24/warren-buffett-berkshire-letter/ ""When Charlie Munger and I buy stocks..."" for these same ideas right from the horse's mouth" To calculate you take the Price and divide it by the Earnings, or by the Sales, or by the Free Cash Flow. Most of these calculations are done for you on a lot of finance sites if the data is available. Such sites as Yahoo Finance and Google Finance as well as my personal favorite: Morningstar Use the Black-Scholes formula. If you know the current price, an options strike price, time until expiration, and risk-free interest rate, then knowing the market price of the option will tell you what the market's estimation of the volatility is. This does rely on a few assumptions, such as Gaussian random walk, but those are reasonable assumptions for most stocks. You can also get a list of past stock prices, put them in Excel, and ask Excel to calculate the standard deviation with stdev.s(), but that gives you the past volatility. The market's estimate of future volatility is more relevant. "The only general rule is ""If you would buy the stock at its current price, hold and possibly buy. If you wouldn't, sell and buy something you believe in more strongly."" Note that this rule applies no matter what the stock is doing. And that it leaves out the hard work of evaluating the stock and making those decisions. If you don't know how to do that evaluation to your own satisfaction, you probably shouldn't be buying individual stocks. Which is why I stick with index funds." "Below I will try to explain two most common Binomial Option Pricing Models (BOPM) used. First of all, BOPM splits time to expiry into N equal sub-periods and assumes that in each period the underlying security price may rise or fall by a known proportion, so the value of an option in any sub-period is a function of its possible values in the following sub period. Therefore the current value of an option is found by working backwards from expiry date through sub-periods to current time. There is not enough information in the question from your textbook so we may assume that what you are asked to do is to find a value of a call option using just a Single Period BOPM. Here are two ways of doing this: First of all let's summarize your information: Current Share Price (Vs) = $70 Strike or exercise price (X) = $60 Risk-free rate (r) = 5.5% or 0.055 Time to maturity (t) = 12 months Downward movement in share price for the period (d) = $65 / $70 = 0.928571429 Upward movement in share price for the period (u) = 1/d = 1/0.928571429 = 1.076923077 ""u"" can be translated to $ multiplying by Vs => 1.076923077 * $70 = $75.38 which is the maximum probable share price in 12 months time. If you need more clarification here - the minimum and maximum future share prices are calculated from stocks past volatility which is a measure of risk. But because your textbook question does not seem to be asking this - you probably don't have to bother too much about it yet. Intrinsic Value: Just in case someone reading this is unclear - the Value of an option on maturity is the difference between the exercise (strike) price and the value of a share at the time of the option maturity. This is also called an intrinsic value.  Note that American Option can be exercised prior to it's maturity in this case the intrinsic value it simply the diference between strike price and the underlying share price at the time of an exercise. But the Value of an option at period 0 (also called option price) is a price you would normally pay in order to buy it. So, say, with a strike of $60 and Share Price of $70 the intrinsic value is $10, whereas if Share Price was $50 the intrinsic value would be $0. The option price or the value of a call option in both cases would be fixed.  So we also need to find intrinsic option values when price falls to the lowest probable and rises to the maximum probable (Vcd and Vcu respectively) (Vcd) = $65-$60 = $5 (remember if Strike was $70 then Vcd would be $0 because nobody would exercise an option that is out of the money) (Vcu) = $75.38-$60 = $15.38 1. Setting up a hedge ratio:  h = Vs*(u-d)/(Vcu-Vcd) h = 70*(1.076923077-0.928571429)/(15.38-5) = 1 That means we have to write (sell) 1 option for each share purchased in order to hedge the risks. You can make a simple calculation to check this, but I'm not going to go into too much detail here as the equestion is not about hedging. Because this position is risk-free in equilibrium it should pay a risk-free rate (5.5%). Then, the formula to price an option (Vc) using the hedging approach is: (Vs-hVc)(e^(rt))=(Vsu-hVcu) Where (Vc) is the value of the call option, (h) is the hedge ratio, (Vs) - Current Share Price, (Vsu) - highest probable share price, (r) - risk-free rate, (t) - time in years, (Vcu) - value of a call option on maturity at the highest probable share price. Therefore solving for (Vc): (70-1*Vc)(e^(0.055*(12/12))) = (75.38-1*15.38) => (70-Vc)*1.056540615 = 60 => 70-Vc = 60/1.056540615 => Vc = 70 - (60/1.056540615)  Which is similar to the formula given in your textbook, so I must assume that using 1+r would be simply a very close approximation of the formula above. Then it is easy to find that Vc = 13.2108911402 ~ $13.21 2. Risk-neutral valuation: Another way to calculate (Vc) is using a risk-neutral approach. We first introduce a variable (p) which is a risk-neutral probability of an increase in share price. p = (e^(r*t)-d)/(u-d) so in your case: p = (1.056540615-0.928571429)/(1.076923077-0.928571429) = 0.862607107 Therefore using (p) the (Vc) would be equal: Vc = [pVcu+(1-p)Vcd]/(e^(rt)) => Vc = [(0.862607107*15.38)+(0.137392893*5)]/1.056540615 => Vc = 13.2071229185 ~ $13.21 As you can see it is very close to the hedging approach. I hope this answers your questions. Also bear in mind that there is much more to the option pricing than this. The most important topics to cover are: Multi-period BOPM Accounting for Dividends Black-Scholes-Merton Option Pricing Model" Definitely a scam. Don't call him or do anything. Stay calm, there is no damage done yet. I met someone online three weeks ago. ... Left his wallet, debit card, credit cards, drivers license, etc. in the room In the entire world its only you he can bank upon ... someone whom hes met online just few weeks ago; there are no relatives, friends !!! why would the hotel manager Fed-Ex or UPS the items to my home address ...  and not to his own address? Upon receipt, the engineer will give me his password to the Bank of America account so he can access his account Why doesn't he have internet? I am supposed to call him in the next hour or so and let him know if I will be doing this tomorrow. Don't call. Don't reply.  The $150 is just a starter bait to see if one is gullible enough to take it and then there is more and more by different ways.