Pump and Dump

An illegal market manipulation scheme in which promoters artificially inflate the price of a thinly traded security through misleading statements, then sell their shares at the peak, leaving later buyers with heavy losses. The scheme is as old as markets themselves -- the South Sea Bubble of 1720 was essentially a pump and dump on a grand scale. Modern versions play out through social media hype, spam emails, and paid stock promoters, and the SEC actively prosecutes these cases.