Another reason I think is that since the halvening, the bull market that everyone have been expecting had failed to materialise. This, with the jolt from the uncertainty news and ETC drama had basically gave the markets a massive sell signal.
A good time to load up on more BTC in preparation for when the halvening actually have a real impact on the supply, and when the Segwit is eventually released. Like it or not, TheDAO mess up had validated the Core dragging its feet in implementing the 2mb HF and avoid pushing for a hasty Segwit.