A new study suggests that spam e-mails advertising penny stocks can have a real effect on the stock market. And someone is making good money as a result — though it's not usually the recipients of the spam. When people respond to the e-mail by buying the advertised stock, it can bump up the price of the stock.
That's when spammers — who bought the stock before they sent the email — sell. Robert Siegel talks with Laura Frieder of Purdue University about her study.