Well here was a good one today. I'm long Dndn but hadn't been following it today. It ran up to $25 and then: "Dendreon's stock, however, suffered a nasty and unexplained blow in a couple of minutes before trading was halted on the Nasdaq exchange ahead of the announcement of the trial results. Between 1:25 p.m. and 1:27 p.m., the stock price fell 69%, to 11.81, at which point trading was stopped. The Nasdaq initially thought a broker's error was to blame for the drop, but later announced the stock trades would stand, according to Bloomberg. The shares more than doubled when trading resumed after hours. " It actually dropped to $7.50 and traded back at $27 after trading resumed once the test results were announced. Needless to say there are alot of pissed off ex-shareholders who had used protective stops on their shares only to see them executed during this nose dive at low prices, and the stock trading at $27 shortly after.