What is down -34% in stock terms?
"The sentence is mathematically wrong and verbally unclear. Mathematically, you calculate the downwards percentage by So, it should be Verbally, the reporter should have written ""The stock is down by 25%"", not ""down by -25%""."
"If markets are efficient they will be unpredictable.  If all past information is already priced into a stock then movement will only occur when new information is introduced.  Since no one can predict future events stocks will move in an unpredictable way.  If markets are inefficient in the short term, people should be able to figure out the long-term price movements.  This doesn't seem to be the case.  This is why the authoritative book on market efficiency is called ""A **Random** Walk Down Wall Street""." I would also be getting out of the stock market if I noticed prices starting to fall and a crash possibly on the way. There are some good and quite simple techniques I would use to time the markets over the medium to long term. I have described some of them in the answer to this question of mine: What are some simple techniques used for Timing the Stock Market over the long term? You could use similar techniques in your investing. And in regards to back-testing DCA to Timing The Markets, I have done that too in my answer to the following question: Investing in low cost index fund — does the timing matter? Timing the Markets wins hand down. In regards to back-testing and the concerns Kent Anderson has brought up, when I back-test a trading strategy, if that strategy is successful, I then forward test it over a year or two to confirm the results. As with back-testing you can sometimes curve fit your criteria too much. By forward testing you are confirming that the strategy is robust over different market conditions. One strategy you can take when the market does start to fall is short selling, as mentioned by some already. I am now short selling using CFDs over the short to medium term as one of my more aggressive strategies. I have a longer term strategy where I do not short, but tighten my stop losses when the market starts to tank. Sometimes my positions will keep going up even though the market as a whole is heading down, and I can make an extra 5% to 10% on these positions before I get taken out. The rare position even continues going up during the whole downturn and when the market starts to recover. So I let the market decide when I get out and when I stay in, I leave my emotions out of it. The best thing you can do is have a written trading plan with all your criteria for getting into the market, your criteria for getting out of the market and your position sizing and risk management incorporated in the plan. "I always liked the answer that in the short term, the market is a voting machine and in the long term the market is a weighing machine. People can ""vote"" a stock up or down in the short term.   In the long term, typically, the intrinsic value of a company will be reflected in the price. It's a rule of thumb, not perfect, but it is generally true. I think it's from an old investing book that talks about ""Mr. Market"".   Maybe it's from one of Warren Buffet's annual letters.    Anyone know? :)" "If you're asking this question, you probably aren't ready to be buying individual stock shares, and may not be ready to be investing in the market at all.  Short-term in the stock market is GAMBLING, pure and simple, and gambling against professionals at that. You can reduce your risk if you spend the amount of time and effort the pros do on it, but if you aren't ready to accept losses you shouldn't be playing and if you aren't willing to bet it all on a single throw of the dice you should diversify and accept lower potential gain in exchange for lower risk. (Standard advice: Index funds.)  The way an investor, as opposed to a gambler, deals with a stock price dropping -- or surging upward, or not doing anything! -- is to say ""That's interesting. Given where it is NOW, do I expect it to go up or down from here, and do I think I have someplace to put the money that will do better?"" If you believe the stock will gain value from here, holding it may make more sense than taking your losses.  Specific example: the mortgage-crisis market crash of a few years ago. People who sold because stock prices were dropping and they were scared -- or whose finances forced them to sell during the down period -- were hurt badly. Those of us who were invested for the long term and could afford to leave the money in the market -- or who were brave/contrarian enough to see it as an opportunity to buy at a better price -- came out relatively unscathed; all I have ""lost"" was two years of growth. So: You made your bet. Now you have to decide: Do you really want to ""buy high, sell low"" and take the loss as a learning experience, or do you want to wait and see whether you can sell not-so-low. If you don't know enough about the company to make a fairly rational decision on that front, you probably shouldn't have bought its stock." You are very correct, rebalancing is basically selling off winners to buy losers. Of course the thinking is that selling a winner that has already increased 100% on the basis that it has doubled so it is likely to go down in the near future. However, just look at Apple as an example, if you bought Apple in June 2009 for $20 (adjusted price) and sold it as part of rebalancing when it rose to $40 (adjusted price) in September 2010, you would have missed out on it reaching over $95 2 years later. Similarly you look to rebalance by buying assets which have been battered (say dropped by 50%) on the basis that it has dropped so much that it should start increasing in the near future. But many times the price can fall even further. A better method would be to sell your winners when they stop being winners (i.e. their uptrend ends) and replace them with assets that are just starting their winning ways (i.e. their downtrend has ended and are now starting to Uptrend). This can be achieved by looking at price action and referring to the definitions of an uptrend and a downtrend. Definition of an uptrend - higher highs and higher lows. Definition of a downtrend - lower lows and lower highs. 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. For a long term gain you must hold the stock a year and a day, so, the long term hold period will fall into 2015 regardless. This is the only tax related issue that occurs to me, did you have something else in mind?  Welcome to Money.SE. "When a question is phrased this way, i.e. ""for tax purposes"" I'm compelled to advise - Don't let the tax tail wag the investing dog.  In theory, one can create a loss, up to the $3K, and take it against ordinary income. When sold, the gains may be long term and be at a lower rate. In reality, if you are out of the stock for the required 30 days, it will shoot up in price. If you double up, as LittleAdv correctly offers, it will drop over the 30 days and negate any benefit. The investing dog's water bowl is half full."