You can't sell a Bitcoin without a buyer, that's how exchanges work. If there is large sell demand, the price gets pushed down. It would behoove a larger holde

You can't sell a Bitcoin without a buyer, that's how exchanges work. If there is large sell demand, the price gets pushed down. It would behoove a larger holder not to sell all at once as this would certainly send the price downward. But at the moment, there is pretty clearly sufficient demand for even the largest holder to dump everything over the course of a week without setting off a panic. Normal average volume is 100-500k BTC/day. But to answer your question, the price would plummet, and new entrants would eagerly buy, that's where the money would come from.