How did this day trader lose so much?
The day trader in the article was engaging in short selling.  Short selling is a technique used to profit when a stock goes down.  The investor borrows shares of a stock from someone else and sells them.  After the stock price goes down, the investor buys the shares back and returns them, pocketing the difference. As the day trader in the article found out, it is a dangerous practice, because there is no limit to the amount of money you can lose. The stock was trading at $2, and the day trader thought the stock was going to go down to $1.  He borrowed and sold 8,400 shares at $2.  He hoped to buy them back at $1 and earn $8,400 profit.  Instead, the stock went up a lot, and he was forced to buy back the shares at $18.50 per share, or about $155,400.  He had had $37,000 with E-Trade, which they took, and he is now over $100,000 in debt. "Learn something new every day... I found this interesting and thought I'd throw my 2c in. Good description (I hope) from Short Selling: What is Short Selling First, let's describe what short selling means when you purchase shares of stock. In purchasing stocks, you buy a piece of ownership in the company. You buy/sell stock to gain/sell ownership of a company. When an investor goes long on an investment, it means that he or she has bought a stock believing its price will rise in the future. Conversely, when an investor goes short, he or she is anticipating a decrease in share price. Short selling is the selling of a stock that the seller doesn't own. More specifically, a short sale is the sale of a security that isn't owned by the seller, but that is promised to be delivered.  Still with us? Here's the skinny: when you short sell a stock, your broker will lend it to you. The stock will come from the brokerage's own inventory, from another one of the firm's customers, or from another brokerage firm. The shares are sold and the proceeds are credited to your account. Sooner or later, you must ""close"" the short by buying back the same number of shares (called covering) and returning them to your broker. If the price drops, you can buy back the stock at the lower price and make a profit on the difference. If the price of the stock rises, you have to buy it back at the higher price, and you lose money. So what happened? The Plan The Reality Lesson I never understood what ""Shorting a stock"" meant until today. Seems a bit risky for my blood, but I would assume this is an extreme example of what can go wrong. This guy literally chose the wrong time to short a stock that was, in all visible aspects, on the decline.  How often does a Large Company or Individual buy stock on the decline... and send that stock soaring? How often does a stock go up 100% in 24 hours? 600%?  Another example is recently when Oprah bought 10% of Weight Watchers and caused the stock to soar %105 in 24 hours. You would have rued the day you shorted that stock - on that particular day - if you believed enough to ""gamble"" on it going down in price." "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."
"The problem with daily-rebalanced ""inverse"" or ""leveraged"" ETFs is that since they rebalance every day, you can lose money even if your guess as to the market's direction is correct. Quoting from FINRA'S guide as to why these are a bad idea: How can this apparent breakdown between longer term index returns and ETF returns happen? Here’s a hypothetical example: let’s say that on Day 1, an index starts with a value of 100 and a leveraged ETF that seeks to double the return of the index starts at $100. If the index drops by 10 points on Day 1, it has a 10 percent loss and a resulting value of 90. Assuming it achieved its stated objective, the leveraged ETF would therefore drop 20 percent on that day and have an ending value of $80. On Day 2, if the index rises 10 percent, the index value increases to 99. For the ETF, its value for Day 2 would rise by 20 percent, which means the ETF would have a value of $96. On both days, the leveraged ETF did exactly what it was supposed to do—it produced daily returns that were two times the daily index returns. But let’s look at the results over the 2 day period: the index lost 1 percent (it fell from 100 to 99) while the 2x leveraged ETF lost 4 percent (it fell from $100 to $96). That means that over the two day period, the ETF's negative returns were 4 times as much as the two-day return of the index instead of 2 times the return. That example is for ""just"" leveraging 2x in the same direction. Inverse funds have the same kind of issue. An example from Bogleheads Wiki page on these kinds of funds says that over 12/31/2007 to 12/31/2010, The funds do exactly what they say on any given day. But any losses get ""locked in"" each day. While normally a 50% loss needs a 100% gain to get back to a starting point, a fund like this needs more than a 100% gain to get back to its starting point. The result of these funds across multiple days doesn't match the index it's matching over those several days, and you won't make money over the long term. Do look at the further examples at the links I've referenced above, or do your own research into the performance of these funds during time periods both when the market is going up and going down. Also refer to these related and/or duplicate questions:" The shift to trading at the close began in 2008. Traders did not want to be caught off guard by surprise news and there was a lot of volatility during the financial crisis, so they would close their position in the evening. Thats how it began. There are two reasons why it sticks around. First, there has been an increase usage of index funds or passive funds. These funds tend to update their positions at the end of the day. From the WSJ: Another factor behind the shift has been the proliferation of passively managed investments, such as index funds. These funds aim to mimic an index, like the S&P 500, by owning the shares that comprise it. Index funds don’t trade as often as active investors, but when they do, it is typically near the market close, traders say. That is because buying or selling a stock at its closing price better aligns their performance with the index they are trying to emulate. The second reason is simply that volume attracts volume. As a result of whats mentioned above, you have a shift to end of day trading, and the corrolary to that is that there is a liquidity shortage from 10am to 3pm. Thus, if you want to buy or sell a stock, but there are few buyers or sellers around, you will significant move the price when you enter your order. Obviously this does not affect retail traders, but imagine hedge funds entering or closing a billion dollar position. It can make a huge impact on price. And one way to mitigate that is to wait until there are more market participants to take the other end of your trade, just as at the end of the day. So this is a self-reinforcing trend that has begun in the markets and will likely stick around. http://www.wsj.com/articles/traders-pile-in-at-the-close-1432768080 "How often do investors really lose money? All the time. And it's almost always reason number 1. Let's start with the beginner investor, the person most likely to make some real losses and feel they've ""learned"" that investing is no better than Vegas. This person typically gets into it because they've been given a hot stock tip, or because they've received a windfall, decided to give this investing lark a try, and bought stock in half a dozen companies whose names they know from their everyday lives (""I own a bit of Google! How cool is that?""). These are people who don't understand the cyclic nature of the market (bear gives way to bull gives way to bear, and on and on), and so when they suddenly see that what was $1000 is now $900 they panic and sell everything. Especially as all the pundits are declaring the end of the world (they always do). Until the moment they sold, they only had paper losses. But they crystallised those losses, made them real, and ended at a loss. Then there's the trend-follower. These are people who don't necessarily hit a bear market, or even a downturn, in their early days, but never really try to learn how the market works in any real sense. They jump into every hot stock, then panic and sell out of anything that starts to go the wrong way. Both of these reactive behaviours seem reasonable in the moment (""It's gone up 15% in the past week? Buy buy buy!"" and ""I've lost 10% this month on that thing? Get rid of it before I lose any more!""), but they work out over time to lots of buying high and selling low, the very opposite of what you want to do. Then there's the day-trader. These are people who sit in their home office, buying and selling all day to try and make lots of little gains that add up to a lot. The reason these people don't do well in the long run is slightly different to the other examples. First, fees. Yes, most platforms offer a discount for ""frequent traders"", but it still ain't free. Second, they're peewees playing in the big leagues. Of course there are exceptions who make out like bandits, but day traders are playing a different game than the people I'd call investors. That game, unlike buy-and-hold investing, is much more like gambling, and day-traders are the enthusiastic amateurs sitting down at a table with professional poker players – institutional investors and the computers and research departments that work for them. Even buy-and-hold investors, even the more sophisticated ones, can easily realise losses on a given stock. You say you should just hold on to a stock until it goes back up, but if it goes low enough, it could take a decade or more to even just break even again. More savvy stock-pickers will have a system worked out, something like ""ok, if it gets down to 90% of what I bought it for, I cut my losses and sell."" This is actually a sensible precaution, because defining hard rules like that helps​ you eliminate emotion from your investing, which is incredibly important if you want to avoid becoming the trend-follower above. It's still a loss, but it's a calculated one, and hopefully over time the exception rather than the rule. There are probably as many other ways to lose money as there are people investing, but I think I've given you a taste. The key to avoiding such things is understanding the psychology of investing, and defining the rules that you'll follow no matter what (as in that last example). Or just go learn about index investing. That's what I did." It has been hinted at in some other answers, but I want to say it explicitly: Volatility is not risk. Volatility is how much an investment goes up and down, risk is the chance that you will lose money. For example, stocks have relatively high volatility, but the risk that you will lose money over a 40 year period is virtually zero (in particular if you invest in index funds). Bonds, on the other hand, have basically no volatility (their cash flow is totally predictable if you trust the future of your government), but there is a significant risk that they will perform worse than stocks over a longer period. So, volatility equals risk only if you are day trading. A 401(k) is literally the opposite of that. For further reading: Never confuse risk and volatility Also, investing is not gambling. Gambling is bad because the odds are stacked against you. You need more than average luck to actually win and the longer you play, the more you will lose. Investing means buying productive capital that will produce further value. The odds are in your favor. Even if you do a moderately bad job at investing, the longer you stay, the more you will win. This image is an advertisement from this week's Barron's. The broker would want to put himself in the best light, correct?  This shows you that of their current accounts, 53.5% are not profitable. And these guys have the best track record of the list. Also keep in mind that their client base isn't random. The winners tend to stay, so even if it were 50/50, the 50% of losers might represent many times that number of people who came to the table, lost their money and left. "In an attempt to express this complicated fact in lay terms I shall focus exclusively on the most influential factor effecting the seemingly bizarre outcome you have noted, where the price chart of VIX ETFs indicates upwards of a 99% decrease since inception. Other factors include transaction costs and management fees.  Some VIX ETFs also provide leveraged returns, describing themselves as ""two times VIX"" or ""three times VIX"", etc. Regarding the claim that volatility averages out over time, this is supported by your own chart of the spot VIX index. EDIT It should be noted that (almost) nobody holds VIX ETFs for anything more than a day or two.  This will miminise the effects described above.  Typical daily volumes of VIX ETFs are in excess of 100% of shares outstanding.  In very volatile markets, daily volumes will often exceed 400% of shares outstanding indicating an overwhelming amount of day trading." Trading is NOT zero-sum game, it is negative sum actually. In fact all people's money is getting swept by commissions and fees. If you don't have The Plan (which includes minimizing commission losses), you win some (not a lot), then you get big positions, then market crashes, then all your money is gone.  You will start noticing that commissions are real, only when you get market crash. Prey that you get heavy losses (-10% of portfolio) before some (giant) market crash. Getting good lesson by small price is better then high price (-30..50%). Piece of advice. There is small exchanges that do NOT charge you for operations, taking only market spread ($0.01) as commission. They do so because they do not have big population and they trade mostly by using automatic market-makers (which means there is no way to buy 10% of Apple there). "What you said was:  &gt; glad to have people skimming billions of dollars from the economy with exactly zero added value  How is that different from what happens in the absence of algo trading?  Why does ""on the matter of minutes"" matter? Is on the matter of hours acceptable to you?  What I know is that 30 years ago, before the rise of algos, human market makers quoted in 8ths and regularly backed away to quarters. If they sensed some information asymmetry or just didn't like your shop, they might not even pick up the phone. The presence of entities that increase volume and thus price discovery, collapse that spread, encourage competition and innovation is beneficial, unless you're ideal economic model is some slow-moving, $-capturing brokerage oligopoly.  Given that, it's on you to bring forward a model that demonstrates some magical specific sub-daily timing is ok but some other speed is ""bad""."