Update (4:05 p.m. EST) The Dow rallied and "picked up 630 points in the final 90 minutes" of trading, Anthony de Rosa at Reuters points out. It closed 429 points up--3.9 percent--for the day. According to the Bespoke Investment Group, this amounts to the 10th largest point gain in the history of the Dow Jones Industrial Average. The rest of the market also recovered with the S&P closing 4.74 percent up and Nasdaq closing 5.29 percent up.
Update (3:52 p.m. EST) The market appears to have rebounded from the low trough reached just after the Fed's announcement. The S&P 500, Nasdaq and the Dow Jones Industrial Average are all back in positive territory for the day. After hitting a low of -1.59 percent, the Dow was trading +0.76 percent at the time of this update.
Update (3:03 p.m. EST) The Wall Street Journal offers a possible explanation for "much of the market freakout:"
Michael Shaoul of Oscar Gruss offers his thoughts: "Long on gloom and short on solution was not a combination that bruised market participants would have wished to see, although even getting this statement out produced dissent at a level unseen during Bernanke's term as Chairman (3 dissenters out of 10 votes cast)."
Update (2:57 p.m. EST) CNN Money sums up the market's behavior in a tweet: "Stocks in wild fluctuation following the Fed statement. Dow falls as much as 195 points, after being up more than 200 points earlier." The stock market has continued to seesaw and oscillating in and out of negative territory for the day. Gold futures, however, closed at a record high $1,743 an ounce.