May 13, 2011

http://goldandsilverblog.com/how-the-comex-crashed-the-silver-market-0235/

"By the close of trading on Wednesday, May 4th, the silver market had experienced significant selling pressure that drove prices down by 17.3% from Thursday, April 28th.  This sell off corresponded exactly to a series of increased margin requirements by the COMEX  for trading silver futures contracts."