“He starts a trend.”
Who would follow Soros and why would Soros want to sell off and lose money?
If I short a stock and then start a run on it by selling stock I hold I can make more money than whatever I stand to lose on my original investment.
Soros does this for a living.
http://www.breitbart.com/london/2016/06/09/soros-shorts-europe-america/