Right, but that's not going to last an entire 24 hours, and total market volume was about double that of present at the peak sale of 2000 BTC, and almost triple the volume for the 8000 BTC sale. That increased volume accounts for a reduced effect. As we saw during the 8000 BTC sale, the price actually went up simultaneously. This is not to mention the fact that arbitrage will quickly absorb the differences between exchanges. Even today, you'd need 20K BTC to move the entire market that same 10%. Given the fact that we saw a drop of almost 70%, the effect of that 40k BTC on higher volumes would have been relatively small. It would move the market only 20% even at today's prices and volumes, only momentarily, and only if it was dumped all at once.