Draw a few trend lines on bitcoinwisdom and you'll see the big dumps are aimed at breaking through them so its fairly obvious where they're coming from. Its been going on for some time, the days destroyed movements suggest they where either involved from 2009 or bough large amounts of coins from people who where. The intent is to either crush bitcoin or take it over and the coin movements suggest the latter, that they're trying to take over mining by forcing competing miners out (new hashing algorithm anyone ). The dumps coming now as well as trading on other markets (forex + others) suggests funds are being pulled in to prop up US markets as they're close to the edge and Argentina's default could push them over, good for us as it leaves them in a weak position.