This may be the reason that gold and silver plunged. But, it goes deeper than this. The bankers knew they would be pulling out of the markets to buy Treasuries, which is propping up the dollar, so, why raise margins on gold and silver if they were going to fall anyway? The excuse they give is the margin increases are due to volatility, not prices. I'm not buying it.
Updated silver lawsuit identifies Morgan trading mechanisms, traders, 'spoof'' and 'fake' trades September 16, 2011
An updated complaint in the class-action lawsuit against JP Morgan / Chase alleging manipulation of the silver futures market, filed this week in U.S. District Court for the Southern District of New York. Details provided on mechanisms of the manipulation & some trades executing it.