Seriously now, maybe there was some rumor in China?
On February 10, 2014, the price took a dip when Mark announced that there was "a bug in bitcoin". It was one of the rare moments since the all-time high when news in the "West" had an effect on the Chinese day-traders. Could it be that the story about today's BitGo bug was mistranslated into Chinese?
Bitfinex shorters led this move. Now they are putting up walls to protect their shorts since some buying started to move against them.