Anatomy of pump'n'dump SPAM

giorgiofr writes: Laura Frieder and Jonathan Zittrain have analized pump'n'dump spam activity in their paper "Spam Works: Evidence from Stock Touts and Corresponding Market Activity". Unbelievably, it appears that spammers are able to achieve a 5% gain on pumped stock before dumping it, along with a dramatic increase in transaction volume of the stock. Paper summary, full paper.