Yes, I believe if someone sells a large quantity of BitCoins at once it can trigger a big sell-off.
Certainly groups of two or three who all sell fairly large quantities of BitCoins around the same time, even just by coincidence, can trigger a panic sell-off.
The more BitCoins are distributed are among more people the less a few people selling can snowball into a price collapse.
BitCoin already seems to be much less volatile than it was even a few months ago. The up-and-down fluctuations are a much smaller percentage of the price. In the last few days it's been hovering around $1200, without falling below $1100 or rising above $1300. A year ago it was routine for BitCoin to lose half its price and then recover and then lose half again.
Certainly groups of two or three who all sell fairly large quantities of BitCoins around the same time, even just by coincidence, can trigger a panic sell-off.
The more BitCoins are distributed are among more people the less a few people selling can snowball into a price collapse.
BitCoin already seems to be much less volatile than it was even a few months ago. The up-and-down fluctuations are a much smaller percentage of the price. In the last few days it's been hovering around $1200, without falling below $1100 or rising above $1300. A year ago it was routine for BitCoin to lose half its price and then recover and then lose half again.