Currently the bitcoin price movement very volatile and very difficult to predict, but it makes traders take advantage from it to make a profit. But this highly volatile price is still complained by bitcoin hunters around the world. I think there are two things that affect the price of bitcoin, including:

1. Small volume of scattered bitcoin
Bitcoin prices are determined in absolute terms by supply and demand. If many buy Bitcoin, then the price will go up and vice versa.
2. The sale of bitcoin on large scale at the same time
when the price of Bitcoin increases, then most people will sell their Bitcoin and if this happens simultaneously and involves many people, the bitcoin price will drop again.

and there are still many other factors affect by bitcoin prices.