1,relationship with Circle too http://www.crunchbase.com/organization/pantera-capital
2,low price = more costumers and it's easy to buy with CC/DC or bank account
3,they are also nice connected together https://panteracapital.com/video/pantera-w14-morehead-athey/
the WAY the wall was eaten is not inconsistent with Pantera being the majority buyer. remember, the wall was jumping around. Pantera could have started nibbling at the wall hoping that the wall would be reset at a lower price, as it had actually been earlier in the day. somewhere around 290 or so, iirc.
also in regards to the OTC buy theory. that theory requires a doubling of a manipulator's risk. they have to not only hope to find a large OTC seller in the middle of the night on a Sunday when no one's working PLUS set up the 30K wall which puts them at risk for losing all of those 30K coins at an artificially low price thus destroying that strategy.
no, if there indeed was manipulation, the easiest and most straight forward way to do it would be to keep selling small and large chunks of BTC at the market over a 4 mo time all the while waiting with a large chunk of fiat on the #1 exchange that you happen to own waiting for a weak BTC loaded whale to panic dump.
if anyone knows of any addresses that are owned by Bitstamp and Pantera, those would be an interesting place to start looking for confirmatory movements or accumulations of BTC.