What is the reason?
What do we not know?
Just a another manipulation for a short pump and dump? We haven't had one of those for quite a time.
A lot of bad fundamentals from around the world which are driving the stock market and the dollar down. In this situation it is natural to see the Bitcoin price rising.
Which by the way means that if there is crisis like 2008, Bitcoin will skyrocket just like gold. Good news!