Losses to online scams more than doubled to $560m from $265m in 2009, as complaints rose 22.3% to 337,000, reported the FBI's Internet Crime Complain Centre (IC3).
Fake e-mails that invoked the FBI's name represented 17% of all complaints. Other popular scams included hitman extortions, astrology readings, economics or "government stimulus" fraud, fake job sites and fake pop-ups for antivirus software.
Just over half the complainants were men, with two-thirds aged 30 to 50. Men lost on average $1.51 to every dollar a woman lost.
Non-delivered goods made up 20% of complaints, followed by identity theft (14%), credit card fraud (10%), auction fraud (10%) and computer fraud (8%).
The costliest crimes were investment fraud, which averaged $3,200 per incident, followed by overpayment fraud ($2,500) and advance fee fraud ($1,500).
The FBI said just over three-quarters of perpetrators were male, and two-thirds lived in the US, although others lived in the UK, Nigeria, Canada, Malaysia and Ghana.