We are sharing some Possible Reason that may lead to this situation, Ups and Down are part of Coins but if you see there is huge price drop then this may be the possible reason for this huge Price Drop.
Selling Bitcoins to Buy Another coins
Today main reason for dropping all coins price today (12/22/2017) in RIPPLE, Ripple is very big in number and any person can use this to manipulate the market, People started selling bitcoins and started buying ripple because price of ripple is very low and that result in huge price drop, on another side trader who holds millions of ripple started selling the ripple at low cost which results in price drop.
Price Drop Due to Rumours
Rumours are the biggest reason for price appreciation and price fall and many news agencies social media and even any layman directly or indirectly push rumors and people who invested on it started selling their coins and which result in a price drop.
If the transaction takes time then people started using some other mode to transfer coins like they will use other coins and price of that coin will start falling.Etherum and Litecoin gain momentum Only because Bitcoin transaction is very slow it takes lot of time to complete, sometime after transfer people see message transaction not found
Negative Trading plays a very important role in Price Drop, there is a giant company who can bear the loss of millions and they manipulate the market in order to gain more from the market so, they started bidding low and which result in a price drop.
So if any trader target bitcoin then the price of all coins will be affected, if you have seen if the price of bitcoin rises then a price of another coin will also rise.
Hope you understand the reason why all crypto coins price is falling.