What's the difference between Buy and Sell price on the stock exchange [duplicate]
The same as when you are buying a car. If a dealer quotes 10k and you quote 8k. 8k is the buy price and 10k is the sell price.  Somebody might quote 8.5k and another dealer might quote 9.5k. The the new price that you see on your screen is 8.5k(Best buy price) and 9.5k(Best sell price). When the buyer and seller agree to an amount, the car(In your case stock) is traded. The Bid price is simply the highest buy price currently being offered and the Ask price simply the lowest sell price being offered. The list of Bid and Ask prices is called the market depth. When the Bid and Ask prices match then a sale goes through. When looking to sell you would generally look at both the Bid and Ask prices. As a seller you want to be matched with the Bid price to get a sale, but you also need to check the current list of Ask prices. If the price you want to sell at is too high you will be placed down the Ask price list, and unless the price moves up to match your sell price you will not end up selling. On the other-hand, if your price to sell is too low and in fact much lower than the current lowest sell price you may get a quick sale but maybe at a lower price than you could have gotten. Similarly, when looking to buy, you would generally also look at both the Bid and Ask prices. As a buyer you want to be matched with the Ask price to get a sale, but you also need to check the current list of Bid prices. If the price you want to buy at is too low you will be placed down the Bid price list, and unless the price moves down to match your buy price you will no end up buying. On the other-hand, if your price to buy is too high and in fact much higher than the current highest buy price you may get a quick purchase but maybe at a higher price than you could have gotten. So, whether buying or selling, it is important to look at and consider both the Bid and Ask prices in the market depth. To add to @Victor 's answer; if you are entering a market order, and not a limit order (where you set the price you want to buy or sell at), then the Ask price is what you can expect to pay to purchase shares of stock in a long position and the Bid price is what you can expect to receive when you sell stock you own in a long position. This is copying my own answer to another question, but this is definitely relevant for you: A bid is an offer to buy something on an order book, so for example you may post an offer to buy one share, at $5. An ask is an offer to sell something on an order book, at a set price. For example you may post an offer to sell shares at $6. A trade happens when there are bids/asks that overlap each other, or are at the same price, so there is always a spread of at least one of the smallest currency unit the exchange allows. Betting that the price of an asset will go down, traditionally by borrowing some of that asset and then selling it, hoping to buy it back at a lower price and pocket the difference (minus interest). Going long, as you may have guessed, is the opposite of going short. Instead of betting that the price will go down, you buy shares in the hope that the price will go up. So, let's say as per your example you borrow 100 shares of company 'X', expecting the price of them to go down. You take your shares to the market and sell them - you make a market sell order (a market 'ask'). This matches against a bid and you receive a price of $5 per share. Now, let's pretend that you change your mind and you think the price is going to go up, you instantly regret your decision. In order to pay back the shares, you now need to buy back your shares as $6 - which is the price off the ask offers on the order book. Similarly, the same is true in the reverse if you are going long. Because of this spread, you have lost money. You sold at a low price and bought at a high price, meaning it costs you more money to repay your borrowed shares. So, when you are shorting you need the spread to be as tight as possible.
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. That is mostly true, in most situations when there are more buy orders than sell orders (higher buy volume orders than sell volume orders), the price will generally move upwards and vice versa, when there are more sell orders than buy orders (higher sell volume orders than buy volume orders), the price will generally move downwards. Note that this does not always happen, but usually it does. You are also correct that for a trade to take place a buyer has to be matched with a seller (or the buy volume matched with the sell volume). But not all orders get executed as trades. Say there are 50 buy orders in the order book with a total volume of 100,000 shares and the highest buy order is currently at $10.00. On the other side there are only 10 sell orders in the order book with total volume of 10,000 shares and the lowest sell order is currently $10.05. At the moment there won't be a trade unless a new buyer or seller enters the market to match the opposing side, or an existing order gets amended upper or lower to match the opposing side. With more demand than supply in the order books what will be the most likely direction that this stock moves in? Most likely the price will move upwards. If a new buyer sees the price moving higher and then looks at the market depth, they would most likely place an order closer to the lowest sell order than the current highest buy order, say $10.01, to be first in line in case a market sell order is placed on the market. As new buy orders enter the market it drives the price higher and higher until the buy orders dry up. Futures exchanges are essentially auction houses facilitating a two-way auction. While they provide a venue for buyers and sellers to come together and transact (be that a physical venue such as a pit at the CME or an electronic network such as Globex), they don't actively seek out or find buyers and sellers to pair them together. The exchanges enable this process through an order book. As a futures trader you may submit one of two types of order to an exchange: Market Order - this is sent to the exchange and is filled immediately by being paired with a limit order.   Limit Order - this is placed on the books of the exchange at the price you specify. If other participants enter opposing market orders at this price, then their market order will be paired with your limit order. In your example, trader B wishes to close his long position. To do this he may enter a market sell order, which will immediately close his position at the lowest possible buy limit price, or he may enter a limit sell order, specifying the price at or above which he is willing to sell. In the case of the limit order, he will only sell and successfully close his position if his order becomes the lowest sell order on the book. All this may be a lot easier to understand by looking at a visual image of an order book such as the one given in the explanation that I have published here: Stop Orders for Futures Finally, not that as far as the exchange is concerned, there is no difference between an order to open and an order to close a position. They're all just 'buy' or 'sell' orders. Whether they cause you to reduce/exit a position or increase/establish a position is relative to the position you currently hold; if you're flat a buy order establishes a new position, if you're short it closes your position and leaves you flat. 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. "This is a misconception. One of the explanations is that if you buy at the ask price and want   to sell it right away, you can only sell at the bid price. This is incorrect. There are no two separate bid and ask prices. The price you buy (your ""bid"") is the same price someone else sells (their ""sell""). The same goes when you sell - the price you sell at is the price someone else buys. There's no spread with stocks. Emphasized it on purpose, because many people (especially those who gamble on stock exchange without knowing what they're doing) don't understand how the stock market works. On the stock exchange, the transaction price is the match between the bid price and the ask price. Thus, on any given transaction, bid always equals ask. There's no spread. There is spread with commodities (if you buy it directly, especially), contracts, mutual funds and other kinds of brokered transactions that go through a third party. The difference (spread) is that third party's fee for assuming part of the risk in the transaction, and is indeed added to your cost (indirectly, in the way you described). These transactions don't go directly between a seller and a buyer. For example, there's no buyer when you redeem some of your mutual fund - the fund pays you money. So the fund assumes certain risk, which is why there's a spread in the prices to invest and to redeem. Similarly with commodities: when you buy a gold bar - you buy it from a dealer, who needs to keep a stock. Thus, the dealer will not buy from you at the same price: there's a premium on sale and a discount on buy, which is a spread, to compensate the dealer for the risk of keeping a stock." "Firstly, if a stock costs $50 this second, the bid/ask would have to be 49/50.  If the bid/ask were 49/51, the stock would cost $51 this second.  What you're likely referring to is the last trade, not the cost.  The last trading price is history and doesn't apply to future transactions. To make it simple, let's define a simple order book.  Say there is a bid to buy 100 at $49, 200 at $48, 500 at $47.  If you place a market order to sell 100 shares, it should all get filled at $49.  If you had placed a market order to sell 200 shares instead, half should get filled at $49 and half at $48.  This is, of course, assuming no one else places an order before you get yours submitted.  If someone beats you to the 100 share lot, then your order could get filled at lower than what you thought you'd get.  If your internet connection is slow or there is a lot of latency in the data from the exchange, then things like this could happen.  Also, there are many ECNs in addition to the exchanges which may have different order books.  There are also trades which, for some reason, get delayed and show up later in the ""time and sales"" window. But to answer the question of why someone would want to sell low... the only reason I could think is they desire to drive the price down." "You should distinguish between the price and the value of a company:  ""Price is what you pay, value is what you get"". Price is the share price you pay for one share of the company. Value is what a company is worth (based on fundamental analysis, one of the principles of value investing).  I would recommend selling the stock only if the company's value has deteriorated due to fundamental changes (e.g. better products from competitors, declining market) and its value is lower than the current share price." "Check your math... ""two stocks, both with a P/E of 2 trading at $40 per share lets say, and one has an EPS of 5 whereas the other has an EPS of 10 is the latter a better purchase?"" If a stock has P/E of 2 and  price of $40 it has an EPS of $20. Not $10. Not $5." "Market price is just the bid or offer price of the last sell or buy order in the market. The price that you actually receive or pay will be the price that the person buying the stock off you or selling it to you will accept. If there are no other participants in the market to make up the other side of your order (i.e. to buy off you if you are selling or to sell to you if you are buying) the exchange pays large banks to be ""market makers""; they fulfil your order using stocks that they don't want to either buy or sell just so that you get your order filled. When you place an order outside of market hours the order is kept on the broker's order books until the market reopens and then, at market opening time there is an opening ""auction"" at which orders are matched to opposing orders (i.e. each buy order will be matched with a sell) at a price determined by auction. You will not know what price the order was filled at until it has been filled. If you want to guarantee a price you can do so by placing a limit order that says not to pay more than a certain price for any unit of the stock." "A ""stock price"" is nothing but the price at which some shares of that stock were sold on an exchange from someone willing to sell those shares at that price (or more) to someone willing to buy them at that price (or less). Pretty much every question about how stock prices work is answered by the paragraph above, which an astonishingly large number of people don't seem to be aware of. So there is no explicit ""tracking"" mechanism at all. Just people buying and selling, and if the current going price on two exchanges differ, then that is an opportunity for someone to make money by buying on one exchange and selling on the other - until the prices are close enough that the fees and overhead make that activity unprofitable. This is called ""arbitrage"" and a common activity of investment banks or (more recently) hedge funds and specialized trading firms spun off by said banks due to regulation." It doesn't matter which exchange a share was purchased through (or if it was even purchased on an exchange at all--physical share certificates can be bought and sold outside of any exchange). A share is a share, and any share available for purchase in New York is available to be purchased in London. Buying all of a company's stock is not something that can generally be done through the stock market. The practical way to accomplish buying a company out is to purchase a controlling interest, or enough shares to have enough votes to bind the board to a specific course of action. Then vote to sell all outstanding shares to another company at a particular fixed price per share. Market capitalization is an inaccurate measure of the size of a company in the first place, but if you want to quantify it, you can take the number of outstanding shares (anywhere and everywhere) and multiply them by the price on any of the exchanges that sell it. That will give you the market capitalization in the currency that is used by whatever exchange you chose. In a perfect market, share prices are by definition a perfect reflection of the true value of a share. Hence, you always get $10 for a share that's worth that much. In reality, the market is imperfect. Prices are somewhat of an average of all different estimates, and there's a cost-of-trading margin between sales and buy prices. Hence, in a perfect market it doesn't matter whether you have a stop loss order at $9.00. That just trades your stock worth $9 for cash worth the same $9. In an imperfect market, that trade nets you less. Furthermore, is risk a linear function of money? Perhaps not, if you bought on margin, need to lend extra and your interest rate increases with the extra credit demand. In a simple statement, no doesn't matter. Checked on my trade portal, everything lines up. Same ISIN, same price(after factoring in FX conversions, if you were thinking about arbitrage those days are long gone).  But a unusual phenomenon I have observed is, if you aren't allowed to buy/sell a stock in one market and try to do that in a different market for the same stock you will still not be allowed to do it. Tried it on French stocks as my current provider doesn't allow me to deal in French stocks. The point is that the bid and ask prices dictate what you can buy and sell at (at market, at least), and the difference between the two, or spread, contributes implicitly to your gains or losses. For example, say your $1 stock actually had a bid of $0.90 and an ask of $1.10; i.e. say that $1 was the last price. You would have to buy the stock at the ask price of $1.10, but now you can only sell that stock at the bid price of $0.90. Thus, you would need to make at least that $0.20 spread before you can make a profit. Not sure where you got the 296 crores figure. The data on the sheet shows activity by category of investors. In the end NET of all BUY and SELL across all categories will always be Zero. It has no bearing on whether the stock market goes up or goes down. If you compare only activity by certain category, say FII then there could be more SELL compared to BUY or vice-versa.