If you really want to know why a peak last December, I can tell you. Wall street was playing a little with cryptos. They were trading it at their highs, and when the fear got into the game ("too high" price, and some people thought prices would go to the "moon"click here), they started to dump most cryptocurrencies. And on January 1st, it became public knowledge, that central banks and wall street were main characters who lead the prices of cryptocurrencies. Governments and banks around the world wanted to regulate cryptos, and crypto crisis happened. Link: http://uk.businessinsider.com/bitcoin-cryptocurrency-market-crash-explained-causes-2018-1