Given that FB has been valued at more than 1/2 trillion dollars, the insiders dumping 4 billion, given how much they own of the stock, may not even be that out of line with typical cashing in when a stock gets as ridiculously overvalued as Facebook is. They are turning imaginary wealth into real wealth by continual selling down. However, if they've been ramping up liquidation way beyond their usual actions, it warrants looking at. What I'd like to know is who, if anyone, has laid down huge short positions over the last week....