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Of course, you can also lose a lot of money this way: if the price goes down instead of up, you will lose ten times the price movement. This is what makes margin trading so risky – it is potentially extremely profitable, but can also be very costly.
Good example Unless you forgot that a skilled trader wont even wait for the price to increase by 10 % then sell it after and to mention that there is a way to actually profitted from using this strategy, which is called as constant percentage execute. Skilled traders are always playing with the market like a bot (if they are doing it manually ) , with that said before doing it , they have put in a limit of each buy or sell.
i.e 1 % each time which means that whenever the price shoots above 1 %, they will constantly sell it for 1 % profit instead of above it for safety practice and also do the same thing whenever the price drop (cut lose)
Heard of this saying :
It is better to get something rather than losing
P.S : my own saying btw

As a matter of fact, this is actually needed for daily trader. Having either good or bad news will bring on the hyping even more active , which you can check from btc-e trollbox regarding how they react due to the KNCminer coins being moved.
Also if you remember correctly on how the news of several months ago regarding paypal accepting BTC is leaked, people are buying like crazy but somewhat the price is going back to where it was weeks later. News do have slight effect for the price but the thing is due to the market being manipulated, we could not even predict wether the X or Y news will bring an impact or no the market
i dont buy direct from exchanges i buy for a resseler that plays with market soo lets say the btc worth around 300 dollars that users charges me 50 dollars above and done...even if he bought btc low or high the user just got some income and always add a rate above the current rate of btc on that day .I dont buy direct because most exchanges ask too many details about the trader and allow wire transfers as credit card and i dont like it.
This is another way a trader profitted from the market though. It is somewhat less risky and much highly proffitable also that it is much more less time-consuming, which you can even check from the currency exchange board whereas most people accept at -3 % stamp rate and sell them at +3 % stamp rate (more or less ) , thus this generate a 6 % overall profit for them
Actually most BTC/FIAT exchangers do ask some question especially your identity since it is involving FIAT though and actually it is a normal procedure around