What causes a stock to drop in price?
A rising tide lifts all ships   Most (but not all) stocks trend along with the general market. Some trend right along with the market (and have a beta at, or very near, one) some follow the Market, but are less sensitive (having a beta of less than one). Some are hypersensitive (and would have a beta of greater than one).  Beta defined  So most of the day to day movement of a stock is because the general market is moving (in the same direction). Of course, exceptional news about the company would cause its price to move independent of the general market. But more often than not the price of a stock moves just because the rest of the market is moving.
"Can it be so that these low-interest rates cause investors to take greater risk to get a decent return?  With interest rates being as low as they are, there is little to no risk in banking; especially after Dodd-Frank. ""Risk"" is just a fancy word for ""Will I make money in the near/ long future."" No one knows what the actual risk is (unless you can see into the future.) But there are ways to mitigate it. So, arguably, the best way to make money is the stock market, not in banking.  There is a great misallocation of resources which at some point will show itself and cause tremendous losses, even maybe cause a new financial crisis? A financial crisis is backed on a believed-to-be strong investment that goes belly-up.  ""Tremendous Losses"" is a rather grand term with no merit. Banks are not purposely keeping interest rates low to cause a financial crisis.  As the central banks have kept interest rates extremely low for a decade, even negative, this affects how much we save and borrow. The biggest point here is to know one thing: bonds. Bonds affect all things from municipalities, construction, to pensions. If interest rates increased currently, the current rate of bonds would drop vastly and actually cause a financial crisis (in the U.S.) due to millions of older persons relying on bonds as sources of income." @Joe.E, I disagree with your logic. The IPO clearly didn't go well--not relative to other IPOs.  Were it not for the stocks underwriters stepping in late in the trading day, Facebook would likely have closed below their opening price. This story and others indicate that institution investors were given negative information by an analyst for the underwriters that other investors didn't have.  This inside knowledge is certainly contributing to the drop in the stock.  It's fair to argue that many individual investors were suckered into buying the stock at the IPO price because of this incomplete disclosure. It wouldn't surprise if what's happens has a negative impact on future trading volume, and creates reluctance to invest in the firm--which would certainly be an additional negative outcome beyond the dropping stock price. Edit: Dilip mentioned a lawsuit.  Here's a link to an article about it. A few reasons.  First, it's hard to buy a stock that has never gone up, and isn't necessarily wise to do so.  Even if you just wait for a stock go down, what if you wait and it goes up two dollars, then drops 10 cents?  Has it gone up or down?  When should you buy it? In general, your idea is correct, the higher the price the less you should want the stock.  But in some sense, the past price is irrelevant, you can't buy it at the past price.  You should buy it now if it's the best option now.  And that is based on your assessment of whether it's future prospects are worth the current price (and in fact enough worth enough to make buying the stock the best economic decision you can currently make). Finally, the price may have gone up for a reason.  The company may have done something, or some information about the company may have become known, that affects it's future prospects.  That might make it a better deal, perhaps even better than it was before the price increase. "So, the term ""ready market"" simply means that a market exists in which there are legitimate buy/sell offers, meaning there are investors willing to own or trade in the security. A ""spot market"" means that the security/commodity is being delivered immediately, rather at some predetermined date in the future (hence the term ""futures market"").  So if you buy oil on the spot market, you'd better be prepared to take immediate delivery, where as when you buy a futures contract, the transaction doesn't happen until some later date.  The advantage for futures contract sellers is the ability to lock in the price of what they're selling as a hedge against the possibility of a price drop between now and when they can/will deliver the commodity.  In other words, a farmer can pre-sell his grain at a set price for some future delivery date so he can know what he's going to get regardless of the price of grain at the time he delivers it.  The downside to the farmer is that if grain prices rise higher than what he sold them for as futures contracts then he loses that additional money.  That's the advantage to the buyer, who expects the price to rise so he can resell what he bought from the farmer at a profit. When you trade on margin, you're basically borrowing the money to make a trade, whether you're trading long (buying) or short (selling) on a security.  It isn't uncommon for traders to pledge securities they already own as collateral for a margin account, and if they are unable to cover a margin call then those securities can be liquidated or confiscated to satisfy the debt.  There still may even be a balance due after such a liquidation if the pledged securities don't cover the margin call. Most of the time you pay a fee (or interest rate) on whatever you borrow on margin, just like taking out a bank loan, so if you're going to trade on margin, you have to include those costs in your calculations as to what you need to earn from your investment to make a profit. When I short trade, I'm selling something I don't own in the expectation I can buy it back later at a lower price and keep the difference.  For instance, if I think Apple shares are going to take a steep drop at some point soon, I can short them.  So imagine I short-sell 1000 shares of AAPL at the current price of $112.  That means my brokerage account is credited with the proceeds of the sale ($112,000), and I now owe my broker 1000 shares of AAPL stock.  If the stock drops to $100 and I ""cover my short"" (buy the shares back to repay the 1000 I borrowed) then I pay $100,000 for them and give them to my broker.  I keep the difference ($12,000) between what I sold them for and what I paid to buy them back, minus any brokerage fees and fees the broker may charge me for short-selling. In conclusion, a margin trade is using someone else's money to make a trade, whether it's to buy more or to sell short.  A short trade is selling shares I don't even own because I think I can make money in the process. I hope this helps." News about a company is not the only thing that affects its stock's price. There is also supply and demand.  That, of course, is influenced by news, but it is not the only actor.  An insider, with a large position in their company's stock, may want to diversify his overall portfolio and thus need to sell a large amount of stock.  That may be significant enough to increase supply and likely reduce the stock's price somewhat. That brings me to another influence on stock price: perception.  Executives, and other insiders with large positions in their company's stock, have to be careful about how and when they sell some of that stock as to not worry the markets.  Many investors watch insider selling to gauge the health of the company. Which brings me to another important point.  There are many things that may be considered news which is material to a certain company and its stock.  It is not just quarterly filings, earnings reports and such.  There is also news related to competitors, news about the economy or a certain sector, news about some weather event that affects a major supplier, news about a major earthquake that will impact the economy of a nation which can then have knock-on effects to other economies, etc... There are also a lot of investors with varying needs which will influence supply and demand.  An institutional investor, needing to diversify, may reduce their position in a stock and thus increase supply enough that it impacts the stock's price.  Meanwhile, individual investors will make their transactions at varying times during the day.  In the aggregate, that may have significant impacts on supply and demand. The overall point being that there are a lot of inputs and a lot of actors in a complicated system.  Even if you focus just on news, there are many things that fall into that category. News does not come out at regular intervals and it does not necessarily spread evenly.  That alone could make for a highly variable environment. You would think that share prices is just a reflection of how well the company is doing but that is not always the case. Sometimes it reflects the investor confidence in the company more than the mere performance. So for instance if some oil company causes some natural disaster by letting one of there oil tankers crash into a coral reef then investor confidence my take a big hit and share prices my fall even if the bottom line of the company was not all that effected. 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. It's the buying and selling of the stock that causes the fluctuation in prices, not the news. People buy and sell all the time, and not just for newsworthy reasons.  They may have to send a child to college, or fix a roof, etc.  Or they may be technical traders looking for signals.  All kinds of reasons.