Can one person cause a crash? Well if there are enough people manipulating the market so they can profit then it's possible for them to cause a crash. For a while Chinese officials have been investigating the stock market crash and it looks like those who they believe were responsible are eventually going to pay for their "crimes." http://fortune.com/2015/11/02/china-arrests-another-market-guru-amid-probe-into-stock-debacle/ One of China’s most prominent private equity investors was arrested Sunday morning on suspicion of insider trading, the state-run news agency Xinhua said . . . from the beginning of this year through August 5, after Chinese stocks crashed 27% over a month and a half, one of his funds gained 357%, according to researcher Private Ranking Net, ranking top among 1,649 funds. Another one of his funds rose by 187%. More witch-hunting?