I would tell you to invest in BTC, ETH, LTC and some other currencies for future, but this is a update to invest fast and for short time? This is based on poloniex charts, so you should check on your exchange how much you could earn.
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BTCD - very likely in next 7 days it will go up to 249% UP
NXC - you can earn about 20-100% , but you should wait few days to see where does it going. It is new currenceis but it started great
XCP - this can be for short term, but also for long term like a month. This is very good currency because it is going up and down very often, so it is very safe to invest. It is very easy to know when to buy and sell. You can earn multiple times about 20-50% or more!
RIC - This one looks very strong for short period. It could go up to 175%, if not in one week, possible in two. It also offer to trade multiple times in few days and earn some extra money untill it goes to about 175%.
XPM - You can earn in short period multiple times much, but you should be carifull, don't buy when it's high, buy when it's on bottom :)
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