500 btc is not a big pump...
Half a million dollars into a low activity coin is a market maker, so I have to disagree. However, OP doesn't have the greatest reputation so I'd be wary to believing any claims he has.
I suppose that's true. Anyway, my guess would be NMC.
That would make me even happier then if it was DVC, but its not NMC. That I know for sure, it hit almost $13 in the last rush, and the daily volume would not move that high with a 500 btc buy, even if it was on btc-e.