The Dow initially fell by nearly 200 points after the release of the FOMC announcement, but quickly rebounded as very oversold conditions lead to short-covering and bargain hunting by traders.
With its 4.0% rally, the Dow posted its largest single-day gain in two years.
http://www.goldalert.com/2011/08/dow-surges-430-points-gold-ends-near-1740/