actually not just selling under-priced bitcoins but buying over-priced bitcoins as well, i.e. trying to empty the market. pretty expensive. doesn't make to much sense to me. any ideas?
It's simple Market manipulation, as to why...
Options:
#1 Crash price to buy back a significant larger amount at a far lower price.
#2 Crash price to devalue BTC of competition. Companies like BFL probably have a large amount of BTC in their wallets, personnel, bills, and raw materials are purchased in $ and not BTC. So if this is done long/often enough it might 'kill' such a company. The same goes for the bigger miners, they need to keep paying their rack hosting costs, power usage, their own bills, etc.
#3 Someone with to much money on hand might be bored and thinks that manipulating the BTC value is fun. If you think that is nuts, realize this. time = money, thus money = time, there are legions of folks that 'waste' their time trolling webforums... ;-)