Determine share price from S-1 for company that was bought before going public
The value of a share depends on the value of the company, which involves a lot more than the value of its assets -- it requires making decisions about what you think will happen to the company in the future. That's inherently not something that can be reduced to a single formula, at least not unless you can figure out how to represent your guesses and your confidence in them in the formula ... and even if you could do all that it would only say what you think the stock is worth; others will be using different numbers and legitimately get different results. Disagreement over value is what the stock market is all about, I'm afraid. "To add to @keshlam's answer slightly a stock's price is made up of several components: the only one of these that is known even remotely accurately at any time is the book value on the day that the accounts are prepared. Even  completed cashflows after the books have been prepared contain some slight unknowns as they may be reversed if stock is returned, for example, or reduced by unforeseen costs.  Future cashflows are based on (amongst other things) how many sales you expect to make in the future for all time. Exercise for the reader: how many iPhone 22s will apple sell in 2029? Even known future cashflows have some risk attached to them; customers may not pay for goods, a supplier may go into liquidation and so need to change its invoicing strategy etc.. Estimating the risk on future cashflows is highly subjective and depends greatly on what the analyst expects the exact economic state of the world will be in the future. Investors have the choice of investing in a risk free instrument (this is usually taken as being modelled by the 10 year US treasury bond) that is guaranteed to give them a return. To invest in anything riskier than the risk free instrument they must be paid a premium over the risk free return that they would get from that. The risk premium is related to how likely they think it is that they will not receive a return higher than that rate. Calculation of that premium is highly subjective; if I know the management of the company well I will be inclined to think that the investment is far less risky (or perhaps riskier...) than someone who does not, for example. Since none of the factors that go into a share price are accurately measurable and many are subjective there is no ""right"" share price at any time, let alone at time of IPO. Each investor will estimate these values differently and so value the shares differently and their trading, based on their ever changing estimates, will move the share price to an indeterminable level. In comments to @keshlam's answer you ask if there is enough information to work out the share price if a company buys out the company before IPO. Dividing the price that this other company paid by the relative ownership structure of the firm would give you an idea of what that company thought that the company was worth at that moment in time and can be used as a surrogate for market price but it will not and cannot accurately represent the market price as other investors will value the firm differently by estimating the criteria above differently and so will move the share price based on their valuation."
Brokerage firms are required to report the number of shares being shorted.  This information is reported to the exchange (NYSE of NASDAQ) and is made public.  Most financial sites indicate the number of shares being shorted for a particular stock.  The image below from Yahoo finance shows 3.29 million shares of CMG were being shorted at the close of 9-28-2012.  This is over 12% of the total outstanding shares of CMG.  For naked short selling additional information is tracked.  If the brokerage is unable to borrow shares to deliver before the settlement date of a short sale then the transaction is recorded as fails-to-deliver.  No money or shares are exchanged since the brokerage is unable to deliver the shares that were agreed upon.  A large amount of fails-to-deliver transactions for a stock usually indicates an excessive amount of naked shorting.  When investors and brokerage firms start to aggressively short a stock they will do so without having borrowed the shares to sell.  This will result in a large amount of naked short selling.  When there are a large number of naked short sellers not all the sellers will be able to borrow the necessary shares before the settlement date and many fails-to-deliver transactions will be recorded. The SEC records the number of fails-to-deliver transactions. The table below summarizes the fails-to-deliver transactions from 1-1-2012 through 9-14-2012 (data obtained from here). The “Ext Amount” column shows the total dollar value of the transactions that failed ( i.e. Fail Qty * Share price ).  The “Volume” column is the total number of shares traded in the same time period.  The “% Volume” shows the percentage of shares that failed to deliver as a percentage of the total market volume. The table orders the data in descending order by the quantity of shares that were not delivered.  Most of the companies at the top of the list no longer exist.  For many of these companies, the quantity of shares that failed to deliver where many multiples of the number of shares traded during the same time period.  This indicates massive naked short selling as many brokerages where unable to find shares to borrow before the settlement date. More information here. "It's been said before, but to repeat succinctly, a company's current share price is no more or less than what ""the market"" thinks that share is worth, as measured by the price at which the shares are being bought and sold. As such, a lot of things can affect that price, some of them material, others ethereal. A common reason to own stock is to share the profits of the company; by owning 1 share out of 1 million shares outstanding, you are entitled to 1/1000000 of that company's quarterly profits (if any). These are paid out as dividends. Two key measurements are based on these dividend payments; the first is ""earnings per share"", which is the company's stated quarterly profits, divided by outstanding shares, with the second being the ""price-earnings ratio"" which is the current price of the stock divided by its EPS. Your expected ""yield"" on this stock is more or less the inverse of this number; if a company has a P/E ratio of 20, then all things being equal, if you invest $100 in this stock you can expect a return of $5, or 5% (1/20). As such, changes in the expected earnings per share can cause the share price to rise or fall to maintain a P/E ratio that the pool of buyers are willing to tolerate. News that a company might miss its profit expectations, due to a decrease in consumer demand, an increase in raw materials costs, labor, financing, or any of a multitude of things that industry analysts watch, can cause the stock price to drop sharply as people look for better investments with higher yields. However, a large P/E ratio is not necessarily a bad thing, especially for a large stable company. That stability means the company is better able to weather economic problems, and thus it is a lower risk. Now, not all companies issue dividends. Apple is probably the most well-known example. The company simply retains all its earnings to reinvest in itself. This is typically the strategy of a smaller start-up; whether they're making good money or not, they typically want to keep what they make so they can keep growing, and the shareholders are usually fine with that. Why? Well, because there's more than one way to value a company, and more than one way to look at a stock. Owning one share of a stock can be seen quite literally as owning a share of that company. The share can then be valued as a fraction of the company's total assets.  Sounds simple, but it isn't, because not every asset the company owns has a line in the financial statements. A company's brand name, for instance, has no tangible value, and yet it is probably the most valuable single thing Apple owns. Similarly, intellectual property doesn't have a ""book value"" on a company's balance sheet, but again, these are huge contributors to the success and profitability of a company like Apple; the company is viewed as a center of innovation, and if it were not doing any innovating, it would very quickly be seen as a middleman for some other company's ideas and products. A company can't sustain that position for long even if it's raking in the money in the meantime. Overall, the value of a company is generally a combination of these two things; by owning a portion of stock, you own a piece of the company's assets, and also claim a piece of their profits. A large company with a lot of material assets and very little debt can be highly valued based solely on the sum of its parts, even if profits are lagging. Conversely, a company more or less operating out of a storage unit can have a patent on the cure for cancer, and be shoveling money into their coffers with bulldozers." Compensation information is available in the annual reports (10-k filings) which are available from the SEC EDGAR system or, generally, the company's website.  Additionally, insider transactions are reported to the SEC so you can see when an insider buys or sells stock or exercises options received as compensation. Background: Nowadays board and officers seem to secretly steal money from shareholders through options and other ways. The stock buybacks that people think should boost the earnings per stock is in reality issued back to the management of the company and is a more stealth way to take money from the company compared to take higher salaries. ... How do you know this is happening if you don't know where to go to get the data needed to determine whether or not this is happening?  Do you really think company share buybacks involve just the amount of shares to pay an executive?  Apple has bought back $117,000,000,000 worth of shares from the fourth quarter 2012 through the second quarter 2016, and paid a pretty substantial amount in dividends over the same period.  Do you really think these shares were simply handed to the executives?  The huge pension funds and other huge investors would not let this slide for very long if it were even close to being true. Don't come to an unfounded conclusion then seek data to prove your position.  Look at and analyze data THEN come to a conclusion. A mutual fund has several classes of shares that are charged different fees. Some shares are sold through brokers and carry a sales charge (called load) that compensates the broker in lieu of a fee that the broker would charge the client for the service.  Vanguard does not have sales charge on its funds and you don't need to go through a broker to buy its shares; you can buy directly from them.  Admiral shares of Vanguard funds are charged lower annual expenses than regular shares (yes, all mutual funds charge expenses for fund adninistration that reduce the return that you get, and Vanguard has some of the lowest expense ratios) but Admiral shares are available only for large investments, typically $50K or so.  If you have invested in a Vanguard mutual fund, your shares can be set to automatically convert to Admiral shares when the investment reaches the right level. A mutual fund manager can buy and sell stocks to achieve the objectives of the fund, so what stockes you are invested in as a share holder in a mutual fund will typically be unknown to you on a day-to-day basis.  On the other hand, Exchange-traded funds (ETFs) are fixed baskets of stocks, and you can buy shares in the ETF.  These shares are bought and sold through a broker (so you pay a transaction fee each time) but expenses are lower since there is no manager to buy and sell stocks: the basket is fixed. Many ETFs follow specific market indexes (e.g. S&P 500).  Another difference between ETFs and mutual funds is that you can buy and sell ETFs at any time of the day just as if you could if you held stocks. With mutual funds, any buy and sell requests  made during the day are processed at the end of the day and the value of the shares that you buy or sell is determined by the closing price of the stocks held by the mutual fund.  With ETFs, you are getting the intra-day price at the time the buy or sell order is executed by your broker. Have the reasons you originally purchased the stock changed? Is the company still sound? Does the company have a new competitor? Has the company changed the way they operate? If the company is the same, except for stock price, why would you change your mind on the company now? ESPECIALLY if the company has not changed, -- but only other people's PERCEPTION of the company, then your original reasons for buying it are still valid.  In fact, if you are not a day-trader, then this COMPANY JUST WENT ON SALE and you should buy more. If you are a day trader, then you do care about the herd's perception of value (not true value) and you should sell. DAY TRADER = SELL BUY AND HOLD (WITH INTELLIGENT RESEARCH) = BUY MORE Since the 2 existing answers addressed the question as asked. Let me offer a warning. You have 10,000 options at $1. You've worked four years and the options are vested. The stock is worth $101 when you get a job offer (at another company) which you accept. So you put up $10k and buy the shares. At this moment, you put up $10K for stock worth $1.01M, a $1M profit and ordinary income.  You got out of the company just in time. For whatever reason, the stock drops to $21 and at tax time you realize the $1M gain was ordinary income, but now the $800k loss is a capital loss, limited to $3000/yr above capital gains. In other words you have $210k worth of stock but a tax bill on $1M.  This is not a contrived story, but a common one from the dotcon bubble. It's a warning that 'buy and hold' has the potential to blow up in your face, even if the shares you buy retain some value. "First, keep in mind that there are generally 2 ways to buy a corporation's shares: You can buy a share directly from the corporation. This does not happen often; it usually happens at the Initial Public Offering [the first time the company becomes ""public"" where anyone with access to the stock exchange can become a part-owner], plus maybe a few more times during the corporations existence. In this case, the corporation is offering new ownership in exchange for a price set the corporation (or a broker hired by the corporation).  The price used for a public offering is the highest amount that the company believes it can get - this is a very complicated field, and involves many different methods of evaluating what the company should be worth. If the company sets the price too low, then they have missed out on possible value which would be earned by the previous, private shareholders (they would have gotten the same share % of a corporation which would now have more cash to spend, because of increased money paid by new shareholders). If the company sets the price too high, then the share subscription might only be partially filled, so there might not be enough cash to do what the company wanted. You can buy a share from another shareholder. This is more common - when you see the company's share price on the stock exchange, it is this type of transaction - buying out other current shareholders. The price here is simply set based on what current owners are willing to sell at. The ""Bid Price"" listed by an exchange is the current highest bid that a purchaser is offering for a single share. The ""Ask Price"" is the current lowest offer that a seller is offering to sell a single share they currently own. When the bid price = the ask price, a share transaction happens, and the most recent stock price changes." "Let's say you see a café. You're looking to buy a café so you walk into one and ask the manager how much profit he makes in a year. He says $N and you walk out and think to yourself, ""I'd be willing to pay $500,000 for this café."" You arrange to meet again to discuss purchasing the business (and he's looking for someone to purchase it).  You go into the store again the following day and the manager says, ""Sorry, I told you we make $N. I've checked the numbers and it's actually only $0.8N (20% lower than what you thought)."" Are you still willing to buy the café for $500,000 as well? No, of course you're not.  I think that this is a sufficient analogy to public companies."