How to explain quick price changes early in the morning
http://www.marketwatch.com/optionscenter/calendar would note some options expiration this week that may be a clue as this would be the typical end of quarter stuff so I suspect it may happen each quarter. http://www.investopedia.com/terms/t/triplewitchinghour.asp would note in part: Triple witching occurs when the contracts for stock index futures,   stock index options and stock options expire on the same day. Triple   witching days happen four times a year on the third Friday of March,   June, September and December. Triple witching days, particularly the   final hour of trading preceding the closing bell, can result in   escalated trading activity and volatility as traders close, roll out   or offset their expiring positions. June 17 would be the 3rd Friday as the 3rd and 10th were the previous two in the month. You may simply be asking why stocks 'gap up' or 'gap down' when the stock market opens. This is because the price adjusts to news that occurred while the exchanges were closed overnight. Perhaps Asian stocks crashed, or perhaps a news story was released in the New York Times about some major company. There are thousands of factors that affect market sentiment, and the big gaps that happen at the open of every trading day is the price of the stocks catching up to those factors. There are lots of good answers on here already.  There are actually lots of answers for this question.  Lots.  I have years of experience on the exchange feed side and there are hundreds and thousands of variables.   All of these variables are funneled into systems owned by large financial institutions (I used to manage these - and only a few companies in the world do this so not hard to guess who I work for).  Their computers then make trades based on all of these variables and equations.  There are variables as whacky as how many times was a company mentioned in an aggregate news feed down to your basic company financials.  But if there is a way to measure a company (or to just guess) there is an equation for it plugged into a super computer at a big bank. Now there are two important factors on why you see this mad dash in the morning: Now most of the rest of the day is also automated trades but by the time you are an hour into market open the computers for the most part have fulfilled their calendar buys.  Everyone else's answer is right too.  There is futures contracts that change, global exchange info changes, options expiring, basic news, whatever but all of these are amplified by the calendar day changing. "The gap up/down and rapid movement immediately following market open is due to overnight futures activity. In your example, SP500 on June 20, 2016 saw a 20-point gap up at market open. This was because the SP500 futures were trading 20 points higher at 9:30 AM than at its close on Friday. The index will always ""catch up"" with futures at market open. You can see that below. The top chart is the E-mini SP500 futures from Sunday night to Monday. Beneath it is the SP500 index."
"He didn't sell in the ""normal"" way that most people think of when they hear the term ""sell."" He engaged in a (perfectly legitimate) technique known as short selling, in which he borrows shares from his broker and sells them immediately. He's betting that the price of the stock will drop so he can buy them back at a lower price to return the borrowed shares back to his broker. He gets to pocket the difference. He had about $37,000 of cash in his account. Since he borrowed ~8400 shares and sold them immediately at $2/share, he got $16,800 in cash and owed his broker 8400 shares. So, his net purchasing power at the time of the short sale was $37,000 + $16,800 - 4800 shares * $2/share. As the price of the stock changes, his purchasing power will change according to this equation. He's allowed to continue to borrow these 8400 shares as long as his purchasing power remains above 0. That is, the broker requires him to have enough cash on hand to buy back all of his borrowed shares at any given moment. If his purchasing power ever goes negative, he'll be subject to a margin call: the broker will make him either deposit cash into his account or close his positions (sell long positions or buy back short positions) until it's positive again. The stock jumped up to $13.85 the next morning before the market opened (during ""before-hours"" trading). His purchasing power at that time was $37,000 + $16,800 - 8400 shares * $13.85/share = -$62,540. Since his purchasing power was negative, he was subject to a margin call. By the time he got out, he had to pay $17.50/share to buy back the 8400 shares that he borrowed, making his purchasing power -$101,600. This $101,600 was money that he borrowed from his broker to buy back the shares to fulfill his margin call. His huge loss was from borrowing shares from his broker. Note that his maximum potential loss is unlimited, since there is no limit to how much a stock can grow. Evidently, he failed to grasp the most important concept of short selling, which is that he's borrowing stock from his broker and he's obligated to give that stock back whenever his broker wants, no matter what it costs him to fulfill that obligation." Ummm, yeah, if you'd like to explain to me how Google is performing poorly, that'd be great. I'd like to have that in a post by tomorrow.   Total revenue has jumped 51% from last year. Just taking a quick look at their financial statements their revenue has increased 1.9 billion from quarter before, to 14.1 billion. Their cash and cash converts are up about 2.5 billion from the quarter before. Finally, their total equity for the company is up about 3.5 billion from the quarter before.  Not bad. If you think this is a bad quarter, I'd love to see what their good quarters are.  What's weighing them down is the buying of Motorola for 13.5 billion. But think about it, they have revenues of that in just *one* quarter. And even more have enough cash to buy Motorola in *cash* 3 times over and still have some left over. I did find this information from the US Department of the Treasury: What are the penalties for withdrawing money early from a Time Certificate of Deposit (CD)? Federal law stipulates that all time certificates of deposit (CD) that are cashed out early are subject to a minimum penalty. If you withdraw an amount within the first six days after deposit, the penalty consists of at least seven days' simple interest. Other than that, national banks can set their own penalties; there is no maximum. Additionally, you may want to review the Account Agreement that the bank provided when you opened the account, as it explains the early withdrawal penalties. Check the paperwork to see if there is a short period at the start where the penalty is minimal. Each bank can set their own rules for the maximum penalty. Some base it on x months interest, some as a percentage of the CD, others may use a more complex formula. &gt; Movie theaters aren't full 99.9% of time  I go a lot, I love seeing movies in the theater, most of the time it's barely 5% full.  As far as cannibalizing people like me who pay full price, that is negligible, people like me that see a few movies a month are such a small fraction of customers.   Others that pay full price will still likely only see one movie per month, but I can't tell you how many times I've been told, or over heard other people saying how the movies are way too expensive to go EVER, unless it's some major event, but even those blockbusters are doing less and less revenue now that people can wait a few months for the DVD or watch it online.  I think this model opens up millions of consumers that gave up on the high cost of taking their family to the movies and also allows far more concession sales. If you have 2 kids, it's about $50 just on the tickets, that's not something most families can afford to do very often.   Personally, I had always suggested a model where a subscription like this would cover mornings and weekdays when theaters are largely empty for those showings. "Trading at the start of a session is by far higher than at any other time of the day. This is mostly due to markets incorporating news into the prices of stocks. In other words, there are a lot of factors that can affect a stock, 24 hours a day, but the market trades for only 6.5 hours a day. So, a lot of news accumulates during the time when people cannot trade on that news. Then when markets finally open, people are able to finally trade on that news, and there is a lot of ""price discovery"" going on between market participants. In the last minutes of trading, volumes increase as well. This can often be attributed to certain kinds of traders closing out their position before the end of the day. For example, if you don't want to take the risk a large price movement at the start of the next day affecting you, you would need to completely close your position." I understand now. Thank you. How important is the existence of effective price discovery tools in a market?   And the example that you gave of a farmer is good, but when I as the owner of a company, get futures regarding, say, the stocks that I own of my company, won't that be insider trading if I do that after knowing that the value of my stocks will fall? If people assume price discovery in this case, won't they also have to assume that I am doing insider trading? Like others have said, mutual funds don't have an intraday NAV, but their ETF equivalents do. Use something like Yahoo Finance and search for the ETF.IV. For example VOO.IV. This will give you not the ETF price (which may be at a premium or discount), but the value of the underlying securities updated every 15 seconds. You should not trade based on what news is just released, if you try you will be too slow to react most of the time. In many cases the news is already priced into the stock during the anticipation of the news being released. Other times as soon as the news is released the price will gap up or down in response to the news.  Some times when you think that the news is good, like new record profits have been achieved, but the share price goes down instead of up. This may be due to the expectation of the record profits by analysts to be 20% more than last year, but the company only achieves 10% more than last year. So the news is actually seen as bad because, even though record profits, it hasn't met expectations. The same can happen in the other direction, a company may make a loss and the share price goes up. This may be because it was expected to make a 50% loss but only made a 20% loss due to cost cutting, so this is seen as a good thing and the price can shoot up, especially if it had been beaten down for months. An other example is when the Federal Reserve in the USA put up interest rates earlier this month. Some may have seen this as bad news and expected share prices to fall, but instead prices rallied. This was actually seen as good news, firstly because it had been expected for a long time, and secondly and more importantly because a small rise in interest rates after many years of near zero rates is a sign of the economy finally starting to improve. If the economy is improving, that means more people will have jobs, more people will be spending more money, companies will start to make higher revenues and start to expand, which means higher profits and higher share prices. A better way to trade is to have a written trading plan and use technical analysis to develop a set of buy and sell criteria that you follow to the tea. Then back test your trading plan through various market conditions to make sure you get a positive expectancy.