This study examines attention-driven investment decisions using a sample of firms essentially unknown to investors prior to becoming the target of a stock spam campaign. We show that the market reaction to spam varies predictably with the content of the spam message. Spam date returns and volume are significantly higher for stocks targeted by spam emails containing optimistic target price projections bundled with ostensibly credible information quoted from a previously issued company press release. There is also some evidence that disclaimers in spam messages reduce, but do not eliminate, the market response. Attention effects also contribute to spammers’ selection of stocks to target and to spam-related enforcement actions by the Securities and Exchange Commission.