"It’s never entirely clear on any given day what causes what in the stock market, but it was pretty obvious that on October 31, Meredith Whitney caused the market in financial stocks to crash. By the end of the trading day, a woman whom basically no one had ever heard of had shaved $369 billion off the value of financial firms in the market. Four days later, Citigroup’s C.E.O., Chuck Prince, resigned."
The End. Good illustration, BTW.