What does it mean when Share price and volume sales aren't negatively correlated?
When stocks have a change in price it is because of a TRADE. To have a trade you have to have both a buyer and a seller.  When the price of a security is going up there are an equal amount of shares being sold as being bought. When the price of a security is going down there are an equal amount of shares being bought as being sold.  There almost always is an unequal amount of shares waiting to be sold compared to the amount waiting to be bought. But waiting shares do not move the price, only when the purchase price and the sale price agree, and a trade occurs, does the price move.  So the price does not go down because more shares are being sold. Neither does the price go up because more shares are being bought.
(Note: I am omitting the currency units.  While I strongly suspect it's US$ I don't know from the chart.  The system works the same no matter what the currency.) A call or a put is the right to sell (put) or buy (call) shares at a certain price on a certain day. This is why you see a whole range of prices.  Not all possible stock values are represented, the number of possibilities has to be kept reasonable.  In this case the choices are even units, for an expensive stock they may be spaced even farther apart than this. The top of the chart says it's for June.  It's actually the third Friday in the month, June 15th in this case.  Thus these are bets on how the stock will move in the next 10 days. While the numbers are per share you can only trade options in lots of 100. The left side of the chart shows calls.  Suppose you sell a call at 19 (the top of the chart)  The last such trade would have gotten you a premium of 9.70 per share (the flip side of this is when the third friday rolls around it will most likely be exercised and they'll be paying you only 19 a share for a stock now trading at something over 26.)  Note the volume, bid and ask columns though--you're not going to get 9.70 for such a call as there is no buyer.  The most anybody is offering at present is 7.80 a share. Now, lets look farther down in the chart--say, a strike price of 30.  The last trade was only .10--people think it's very unlikely that FB will rise above 30 to make this option worthwhile and thus you get very little for being willing to sell at that price.  If FB stays at 26 the option will expire worthless and go away.  If it's up to 31 when the 15th rolls around they'll exercise the option, take your shares and pay you 30 for them.  Note that you already gave permission for the trade by selling the call, you can't back out later if it becomes a bad deal. Going over to the other side of the chart with the puts: Here the transaction goes the other way, come the 15th they have the option of selling you the shares for the strike price.  Lets look at the same values we did before.  19?  There's no trading, you can't do it. 30?  Here you will collect 3.20 for selling the put.  Come the 15th they have the right to sell you the stock for 30 a share.  If it's still 26 they're certainly going to do so, but if it's up to 31 it's worthless and you pocket the 3.20 Note that you will normally not be allowed to sell a call if you don't own the shares in question.  This is a safety measure as the risk in selling a call without the stock is infinite.  If the stock somehow zoomed up to 10,000 when the 15th rolls around you would have to come up with the shares and the only way you could get them is buy them on the open market--you would have to come up with a million dollars.  If there simply aren't enough shares available to cover the calls the result is catastrophic--whoever owns the shares simply gets to dictate terms to you.  (And in the days of old this sometimes happened.) "I think you've got basics, but you may have the order / emphasis a bit wrong. I've changed the order of the things you've learned in to what I think is the most important to understand: Owning a stock is like owning a tiny chunk of the business Owning stock is owning a tiny chunk of the business, it's not just ""like"" it. The ""tiny chunks"" are called shares, because that is literally what they are, a share of the business. Sometimes shares are also called stocks. The words stock and share are mostly interchangeable, but a single stock normally means your holding of many shares in a business, so if you have 100 shares in 1 company, that's a stock in that company, if you then buy 100 shares in another company, you now own 2 stocks. An investor seeks to buy stocks at a low price, and sell when the price is high. Not necessarily. An investor will buy shares in a company that they believe will make them a profit. In general, a company will make a profit and distribute some or all of it to shareholders in the form of dividends. They will also keep back a portion of the profit to invest in growing the company. If the company does grow, it will grow in value and your shares will get more valuable. Price (of a stock) is affected by supply/demand, volume, and possibly company profits The price of a share that you see on a stock ticker is the price that people on the market have exchanged the share for recently, not the price you or I can buy a share for, although usually if people on the market are buying and selling at that price, someone will buy or sell from you at a similar sort of price. In theory, the price will be the companies total value, if you were to own the whole thing (it's market capitalisation) divided by the total number of shares that exist in that company. The problem is that it's very difficult to work out the total value of a company. You can start by counting the different things that it owns (including things like intellectual property and the knowledge and experience of people who work there), subtract all the money it owes in loans etc., and then make an allowance for how much profit you expect the company to make in the future. The problem is that these numbers are all going to be estimates, and different peoples estimates will disagree. Some people don't bother to estimate at all. The market makers will just follow supply and demand. They will hold a few shares in each of many companies that they are interested in. They will advertise a lower price that they are willing to buy at and a higher price that they will sell at all the time. When they hold a lot of a share, they will price it lower so that people buy it from them. When they start to run out, they will price it higher. You will never need to spend more than the market makers price to buy a share, or get less than the market makers price when you come to sell it (unless you want to buy or sell more shares than they are willing to). This is why stock price depends on supply and demand. The other category of people who don't care about the companies they are trading are the high speed traders. They just look at information like the past price, the volume (total amount of shares being exchanged on the market) and many other statistics both from the market and elsewhere and look for patterns. You cannot compete with these people - they do things like physically locate their servers nearer to the stock exchanges buildings to get a few milliseconds time advantage over their competitors to buy shares quicker than them." "In general, there should be a ""liquidity premium"" which means that less-liquid stocks should be cheaper. That's because to buy such a stock, you should demand a higher rate of return to compensate for the liquidity risk (the possibility that you won't be able to sell easily). Lower initial price = higher eventual rate of return. That's what's meant when Investopedia says the security would be cheaper (on average). Is liquidity good? It depends. Here's what illiquidity is. Imagine you own a rare piece of art. Say there are 10 people in the world who collect this type of art, and would appreciate what you own. That's an illiquid asset, because when you want to sell, maybe those 10 people aren't buying - maybe they don't want your particular piece, or they all happen to be short on funds. Or maybe worse, only one of them is buying, so they have all the negotiating leverage. You'll have to lower your price if you're really in a hurry to sell. Maybe if you lower your price enough, you can get one of the 10 buyers interested, even if none were initially. An illiquid asset is bad for sellers. Illiquid means there aren't enough buyers for you to get a bidding war going at the time of your choosing. You'll potentially have to wait around for buyers to turn up, or for a stock, maybe you'd have to sell a little bit at a time as buyers want the shares. Illiquid can be bad for buyers, too, if the buyer is for some reason in a hurry; maybe nobody is selling at any given time. But, usually buyers don't have to be in a hurry. An exception may be if you short sell something illiquid (brokers often won't let you do this, btw). In that case you could be a forced buyer and this could be very bad on an illiquid security. If there are only one or two sellers out there, they now have the negotiating leverage and they can ask whatever price they want. Illiquidity is very bad when mixed with margin or short sales because of the potential for forced trades at inopportune times. There are plenty of obscure penny stocks where there might be only one or two trades per day, or fewer. The spread is going to be high on these because the bids at a given time will just be lowball offers from buyers who aren't really all that interested, unless you want to give your stock away, in which case they'll take it. And the asks are going to be from sellers who want to get a decent price, but maybe there aren't really any buyers willing to pay, so the ask is just sitting there with no takers. The bids and asks may be limit orders that have been sitting open for 3 weeks and forgotten about. Contrast with a liquid asset. For example, a popular-model used car in good condition would be a lot more liquid than a rare piece of art, though not nearly as liquid as most stocks. You can probably find several people that want to buy it living nearby, and you're not going to have to drop the price to get a buyer to show up. You might even get those buyers in a bidding war. From illiquid penny stocks, there's a continuum all the way up to the most heavily-traded stocks such as those in the S&P500. With these at a given moment there will be thousands of buyers and sellers, so the spread is going to close down to nearly zero. If you think about it, just statistically, if there are thousands of bids and thousands of asks, then the closest bid-ask pair is going to be close together. That's a narrow spread. While if there are 3 bids and 2 asks on some illiquid penny stock, they might be dollars away from each other, and the number of shares desired might not match up. You can see how liquidity is good in some situations and not in others. An illiquid asset gives you more opportunity to get a good deal because there aren't a lot of other buyers and sellers around and there's some opportunity to ""negotiate"" within the wide spread. For some assets maybe you can literally negotiate by talking to the other party, though obviously not when trading stocks on an exchange. But an illiquid asset also means you might get a bad deal, especially if you need to sell quickly and the only buyers around are making lowball offers. So the time to buy illiquid assets is when you can take your time on both buying and selling, and will have no reason for a forced trade on a particular timeline. This usually means no debt is involved, since creditors (including your margin broker) can force you to trade. It also means you don't need to spend the money anytime soon, since if you suddenly needed the money you'd have a forced trade on your hands. If you have the time, then you put a price out there that's very good for you, and you wait for someone to show up and give you that price - this is how you get a good deal. One more note, another use of the term liquid is to refer to assets with low or zero volatility, such as money market funds. An asset with a lot of volatility around its intrinsic or true value is effectively illiquid even if there's high trade volume, in that any given point in time might not be a good time to sell, because the price isn't at the right level. Anyway, the general definition of a liquid investment is one that you'd be comfortable cashing out of at a moment's notice. In this sense, most stocks are not all that liquid, despite high trading volume. In different contexts people may use ""liquid"" in this sense or to mean a low bid-ask spread." "You might consider learning how the ""matching"" or ""pairing"" system in the market operates.  The actual exchange only happens when both a buyer and a seller overlap their respect quotes.   Sometimes orders ""go to market"" for a particular volume.  Eg get me 10,000 Microsoft shares now.  which means that the price starts at the current lowest seller, and works up the price list until the volume is met.  Like all market it trades, it has it's advantages, and it's dangers.  If you are confident Microsoft is going to bull, you want those shares now, confident you'll recoup the cost.  Where if you put in a priced order, you might get only none or some shares. Same as when you sell.  If you see the price (which is the price of the last completed ""successful"" trade.  and think ""I'm going to sell 1000 shares"". then you give the order to the market (or broker), and then the same as what happened as before.  the highest bidder gets as much as they asked for, if there's still shares left over, they go to the next bidder, and so on down the price... and the last completed ""successful"" trade is when your last sale is made at the lowest price of your batch. If you're selling, and selling 100,000 shares. And the highest bidder wants 1,000,000 shares you'll only see the price drop to that guys bid.  Why will it drop (off the quoted price?).  Because the quoted price is the LAST sale, clearly if there's someone still with an open bid on the market...then either he wants more shares than were available (the price stays same), or his bid wasn't as high as the last bid (so when you sale goes through, it will be at the price he's offering).   Which is why being able to see the price queues is important on large traders. It is also why it can be important put stops and limits on your trades, een through you can still get gapped if you're unlucky.  However putting prices (""Open Orders"" vs ""(at)Market Orders"") can mean that you're sitting there waiting for a bounce/spike while the action is all going on without you). safer but not as much gain (maybe ;) ) that's the excitement of the market, for every option there's advantages...and risks... (eg missing out) There are also issues with stock movement, shadowing, and stop hunting, which can influence the price. But the stuff in the long paragraphs is the technical reasons." 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. Volumes are used to predict momentum of movement, not the direction of it. Large trading volumes generally tend to create a price breakout in either positive or negative direction. Especially in relatively illiquid stocks (like small caps), sudden volume surges can create sharp price fluctuations. There are several reasons why this may happen and I will update as I get more information from you. Volumes on that stock look low (supposing that they are either in a factor between 1s and 1000s) so it could well be that there was no volume on that day. If no trades occur then open, high and low are meaningless as they are statistics based on trades that occur that day and no trades occur. Remember that there has to be volume to get a price. The stock may have been frozen by either the exchange or the company for the day. This could be for various reasons including to prevent some illegal activity. In that case no trades were made because the market for that stock was closed. Another possibility is that all trades that day were cancelled by the exchange. The exchange may cancel all trades if there is unusual, potentially fraudulent or other illegal activity on the stock. In this case the last price for that day existed but was rolled back by the exchange and never occurred. This is a rare situation. Although I can't find any holidays on that date it is possible that this is how your data provider marks market holidays. It would be valid to ignore the data in that case as being from a non-market day. I cannot tell if this is possible without knowing exchange information. There is a possibility that some data providers don't receive data for a day or that it gets corrupted. It may be worth checking another source to ensure the integrity of the data that you are receiving. Whichever reason is true, the data provider has made the close equal to the previous day's close as no price movements occurred. Strictly the closing price is the price of the last trade made for that day and so should be null (and open, high and low should be null too and not 0 otherwise the price change on day is very large!). Therefore, to keep integrity, you have a few choices: "In theory, say we had two soft drink companies, and no other existed. On Jan 1, they report they each had 50% market share for the past year. Over the next year, one company's gain is the other's loss. But over the year, for whatever reason, the market has grown 10% (all the stories of bad water helped this), and while the market share ends at 49/51, the 49 guy has improved his margins, and that stock rises by more than the other.  In general, companies in the same industry will be positively correlated, and strongly so.  I offer my ""spreadsheets are your friend"" advice. I took data over the last 10 years for Coke and Pepsi. Easy to pull from various sites, I tend to use Yahoo. In Excel the function CORREL with let you compare two columns of numbers for correlation. I got a .85 result, pretty high. To show how a different industry would have a lower correlation, I picked Intel. Strangely, enough, Intel and Pepsi had a .94 correlation. A coincidence, I suppose, but my point is that you can easily get data and perform your own analysis to better understand what's going on."