Pump-and-dump spam
Spam promoting stocks to inflate their value
Like the '419 scam', pump-and-dump spam campaigns are a type of fraud dating back to pre-internet times, using the mass medium of email to broaden their potential range where earlier incarnations used postal services or telephone cold-calling.
The scam involves the perpetrators purchasing a quantity of stocks and shares, usually cheap 'penny stocks'. They then send out (pump) emails hyping the value of the company, usually implying that the company has made some major new deal or discovery and that the value of the shares is tipped to rise dramatically. Other campaigns simply include the name of the firm or the company logo, leaving the imagination of keen investors to do the rest.
If enough victims are tricked into investing in the shares, the value does indeed rise, and the scammers then sell (dump) their shares for a profit. As pump-and-dump requires no contact between victim and scammer after the initial spam run, the perpetrators of the scam are often harder to track than in other forms of spam fraud.