Bernanke: the Fed will “act as needed”
“The Federal Reserve stands ready to take additional actions as needed to provide liquidity and promote the orderly functioning of markets.”
Thus the chairman spoke and the market rallied. http://www.bloomberg.com/apps/news?pid=20601087&sid=aOuMwc5hdJQ0&refer=home
Full text of the Ben Bernanke speech: http://graphics8.nytimes.com/packages/pdf/business/20070831Bernanke.pdf