Potomac, typically a market maker will pay people to post negatively in hope of creating panic selling, and that does work. More commonly a group of investors who bought low will sell higher gambling that no news will come out to counter their selling. This in turn creates panic selling. However, the real question is why? There needs to be a reason for each of these tactics, and that reason is generally the knowledge or strong inkling that something big is about to happen that will allow them to buy back low and then once again sell even higher.