Reason is unknown and this is crypto's nature to have a fall and hike. I am sure this should be a last fall for this 4th Quarter. We have been seeing a constant growth in last few weeks. And let's look at the positive progress. The price does not go below certain price and this keeps Bitcoin holders more vibrant and confident. Do not worry about the fluctuation and we need it in crypto. Fluctuations are the object to its growth.