My bet is on insiders. Really bad news incoming soon.
Correction was expected/due anyway. Even at $600 bitcoin was still overbought. We just haven't seen the end of the post-December ATH adjustment yet. It looked like it for a bit but then some whale confused everything. This is just picking up where we left off.
TERA and Arepo might nuance it better but as I see it $400-500 is closer to where bitcoin "should" be at the moment.