Why are some of the biggest names in the corporate world unloading stock like there is no tomorrow, and why are some of the most prominent investors on Wall Street loudly warning about the possibility of a market crash? Should we be alarmed that the big dogs on Wall Street are starting to get very nervous? In a previous article, I got very excited about a report that indicated that corporate insiders were selling nine times more of their own shares than they were buying. Well, according to a brand new Bloomberg article, insider sales of stock have outnumbered insider purchases of stock by a ratio of twelve to one over the past three months.