I see that price dropped from 1000$ to 150$, why?
Also a small volume for such a big coin..

Most coins have dropped price in the past month.
That's not the main reason for the jump of Byteball price. That's true that most coins are going downward.
But for Byteball, it jumped more: from top 50 to below 110th. The main reason came from the sets of operations, such as the (continuous) changes of distribution models.