How is stock price determined?
Yes, stock price is determined by the last trade price. There are always going to be people who have put in a price to buy a stock (called a bid price) and people who have put in a price to sell a stock (called an ask price). Based on your example, if the last trade price for the stock was $1.23, then you might have the following bid prices and ask prices: So if you put in a limit order to buy 100 shares at $100, you would buy the 40 shares at $1.23, the 15 shares at $1.24, and the 45 shares $1.25.  The price of the stock would go up to $1.25. Conversely, if you put in a limit order to sell 100 shares at $0.01 (I don't think any broker would allow a sell price of $0.00), you would sell 30 shares at $1.22, 20 shares at $1.21, and 50 shares at $1.20.  The price of the stock would go down to $1.20. Stock price is determined by what's being asked for it, and what's being paid for it. The reported price is either a recent average, or is the last price at which a sale actually took place, depending on which you've asked for. Limit orders are an agreement between you and your brokerage, and have no direct effect on price. When and if their condition is triggered and the transaction takes place, the transaction is what's significant. "You can interpret prices in any way you wish, but the commonly quoted ""price"" is the last price traded. If your broker routes those orders, unlikely because they will be considered ""unfair"" and will probably be busted by the exchange, the only way to drive the price to the heights & lows in your example is to have an overwhelming amount of quantity relative to the order book. Your orders will hit the opposing limit orders until your quantity is exhausted, starting from the best price to the worst price. This is the functional equivalent to a market order." "The answer to each of your questions is no. It is important to appreciate that the ""quoted"" ticker price may be delayed by say 15 minutes, and thus is not ""real-time."""
Opening - is the price at which the first trade gets executed at the start of the trading day (or trading period). High - is the highest price the stock is traded at during the day (or trading period). Low - is the lowest price the stock is traded at during the day (or trading period). Closing - is the price at which the last trade gets executed at the end of the trading day (or trading period). Volume - is the amount of shares that get traded during the trading day (or trading period). For example, if you bought 1000 shares during the day and another 9 people also bought 1000 shares each, then the trading volume for the day would be 10 x 1000 = 10,000. "Share price is based on demand.  Assuming the same amount of shares are made available for trade then stocks with a higher demand will have a higher price.  So say a company has 1000 shares in total and that company needs to raise $100. They decide to sell 100 shares for $1 to raise their $100. If there is demand for 100 shares for at least $1 then they achieve their goal. But if the market decides the shares in this company are only worth 50 cents then the company only raises $50. So where do they get the other $50 they needed? Well one option is to sell another 100 shares. The dilution comes about because in the first scenario the company retains ownership of 900 or 90% of the equity. In the second scenario it retains ownership of only 800 shares or 80% of the equity. The benefit to the company and shareholders of a higher price is basically just math. Any multiple of shares times a higher price means there is more value to owning those shares. Therefore they can sell fewer shares to raise the same amount.  A lot of starts up offer employees shares as part of their remuneration package because cash flow is typically tight when starting a new business. So if you're trying to attract the best and brightest it's easier to offer them shares if they are worth more than those of company with a similar opportunity down the road. Share price can also act as something of a credit score. In that a higher share price ""may"" reflect a more credit worthy company and therefore ""may"" make it easier for that company to obtain credit. All else being equal, it also makes it more expensive for a competitor to take over a company the higher the share price. So it can offer some defensive and offensive advantages. All ceteris paribus of course." "You can think of the situation as a kind of Nash equilibrium.  If ""the market"" values stock based on the value of the company, then from an individual point of view it makes sense to value stock the same way. As an illustration, imagine that stock prices were associated with the amount of precipitation at the company's location, rather than the assets of the company.  In this imaginary stock market, it would not benefit you to buy and sell stock according to the company's value.  Instead, you would profit most from buying and selling according to the weather, like everyone else.  (Whether this system — or the current one — would be stable in the long-term is another matter entirely.)" The stock price is what people think a company is worth, this is made up of When a company pays out a dividend the money in the company’s bank account reduces, therefore the value of the company reduces.    When a company says they are going to pay a larger dividend than expected, we start to expect they are going to make more profit next year as well. So stock price tends to go up when a company says it is increasing the dividend, but down on the day then money leaves the companies bank account.   There is normally many months between the two events. "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." Points are the units of measurement of the index. They're calculated based on the index formula, which in turn based on the prices of the underlying stocks. Movement in points is not really interesting, the movement as a percentage of the base price (daily opening, usually) is more interesting since it gives more context. 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. Look at the how the income statement is built. The stock price is nowhere on it. The net income is based on the revenue (money coming in) and expenses (money going out).  Most companies do not issue stock all that often. The price you see quoted is third parties selling the stock to each other. "Stock price is determined by the buyers and sellers, correct? Correct! ""Everything is worth what its purchaser will pay for it""-Publius Syrus What causes people to buy or sell? Is it news? earnings? stock analysis and techniques? All of these things influence investors' perception of how much a stock is worth. If AMZN makes a lot of money one quarter, then the price might go up. But maybe public perception of AMZN changes because of a large scandal. This could cause the share price to decline even with the favorable earnings report. Why do these 'good' or 'bad' news make people want to buy/sell a stock? People invest to make money. If it looks like a company is going to take a turn for the worst, people will sell. If it looks like the company has a bright, cash-laden future in front of them, people will buy. News is one of the many factors people use to determine how well a company will do. Theoretically could a bunch of people short AMZN and drive down the price regardless of how well it is doing? Say investors wanted to boycott AMZN in order to drive down the cost and get some cheap shares. This is pretty silly, but say for the sake of the argument that everyone who owned AMZN decided to sell their shares and no other investor was willing to buy the shares for less than $0.01, then AMZN shares would be ""worth"" $0.01 in that aspect. That is extremely unlikely to happen, though, for two reasons:" "Price is decided by what shares are offered at what prices and who blinks first.  The buyer and seller are both trying to find the best offer, for their definition of best, within the constraints then have set on their bid or ask. The seller will sell to the highest bid they can get that they consider acceptable. The buyer will buy from the lowest offer they can get that they consider acceptable. The price -- and whether a sale/purchase happens at all -- depends on what other trades are still available and how long you're willing to wait for one you're happy with, and may be different on one share than another ""at the same time"" if the purchase couldn't be completed with the single best offer and had to buy from multiple offers. This may have been easier to understand in the days of open outcry pit trading, when you could see just how chaotic the process is... but it all boils down to a high-speed version of seeking the best deal in an old-fashioned marketplace where no prices are fixed and every sale requires (or at least offers the opportunity for) negotiation. ""Fred sells it five cents cheaper!"" ""Then why aren't you buying from him?"" ""He's out of stock."" ""Well, when I don't have any, my price is ten cents cheaper."" ""Maybe I won't buy today, or I'll buy elsewhere. ""Maybe I won't sell today. Or maybe someone else will pay my price. Sam looks interested..."" ""Ok, ok. I can offer two cents more."" ""Three. Sam looks really interested."" ""Two and a half, and throw in an apple for Susie."" ""Done."" And the next buyer or seller starts the whole process over again. Open outcry really is just a way of trying to shop around very, very, very fast, and electronic reconciliation speeds it up even more, but it's conceptually the same process -- either seller gets what they're asking, or they adjust and/or the buyer adjusts until they meet, or everyone agrees that there's no agreement and goes home." 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. "Stock returns cannot be evaluated on its own. You need to take into account inflation and the return of other investment vehicles. Over the long run, you want to earn more than your peers (ie inflation), or lose less than them. Stock lets you buy into the profits of a company managed by others. So the fundamental question is ""do those company managers make better decision than average person?"" Of course there are times when they make awful decisions (eg just before dotcom bubble), and sometimes the best decision is to close the business. But overall those people are much better educated, have higher IQ, more resourceful, etc, and so over long time and across all the companies, this is correct and hence the stock market premium." "TL;DR: Because stocks represent added value from corporate profits, and not the price the goods themselves are sold at. This is actually a very complicated subject.  But here's the simplest answer I can come up with.  Stocks are a commodity, just like milk, eggs, and bread.  The government only tracks certain commodities (consumables) as part of the Consumer Price Index (CPI).  These are generally commodities that the typical person will consume on a daily or weekly basis, or need to survive (food, rent, etc.).  These are present values. Stock prices, on the other hand, represent an educated guess (or bet) on a company's future performance.  If Apple has historically performed well, and analysts expect it to continue to perform, then investors will pay more for a stock that they feel will continue pay good dividends in the future.  Compound this with the fact that there is usually limited a supply of stock for a particular company (unless they issue more stock). If we go back to Apple as an example, they can raise their price they charge on an iPhone from $400 to $450 over the course of say a couple years.  Some of this may be due to higher wage costs, but efficiencies in the marketplace actually tend to drive down costs to produce goods, so they will probably actually turn a higher profit by raising their price, even if they have to pay higher wages (or possibly even if they don't raise their price!).  This, in economics, is termed value added. Finally, @Hart is absolutely correct in his comment about the stocks in the S&P 500 not being static.  Additionally, the S&P 500 is a hand picked set of ""winners"", if you will.  These are not run-of-the-mill penny stocks for companies that will be out of business in a week.  These are companies that Standard & Poor's Financial Services LLC thinks will perform well." "Most of the time* you're selling to other investors, not back to the company. The stock market is a collection of bid (buy offers) and asks (sell offers). When you sell your stock as a retail investor at the ""market"" price you're essentially just meeting whatever standing bid offers are on the market.  For very liquid stocks (e.g. Apple), you can pretty much always get the displayed price because so many stocks are being traded. However during periods of very high volatility or for low-volume stocks, the quoted price may not be indicative of what you actually pay.  As an example, let's say you have 5 stocks you're trying to sell and the bid-side order book is 2 stocks for $105, 2 for $100, and 5 for $95. In this scenario the quoted price will be $105 (the best bid price), but if you accept market price you'll settle 2 for 105, 2 for 100, and 1 for 95. After your sell order goes through, the new quoted price will be $95. For high volume stocks, there will usually be so many orders near the midpoint price ($105, in this case) that you won't see any price slippage for small orders.  You can also post limit orders, which are essentially open orders waiting to be filled like in the above example. They ensure you get the price you want, but you have no way to guarantee they'll be filled or not.  Edit: as a cool example, check out the bitcoin GDAX on coinbase for a live example of what the order book looks like for stocks. You'll see that the price of bitcoin will drift towards whichever direction has the less dense order book (e.g. price drifts upwards when there are far more bids than asks.)" Ideally, stock price reflects the value of the company, the dividends it is expected to pay, and what people expect the future value of the company to be. Only one of those (maybe one and a half) is related to current  sales, and not always directly. Short-term motion of a stock is even less directly linked, since it also reflects previous expectations. A company can announce disappointing sales and see its stock go up, if the previous price was based on expecting  worse news.