U2 are performing under a giant "claw" structure on their world tour

U2 raked in more money than any other music act in the US in 2009, according to Billboard magazine.

The music journal said U2 made $109m (£71m) from touring, record sales and other royalties - almost twice as much as the second best, Bruce Springsteen.

Springsteen took home $58m (£38m), followed by Madonna with $47m (£31m) and rockers AC/DC with $44m (£29m).

U2 are in the middle of a mammoth world tour and touring is the most lucrative activity for artists, Billboard said.

The 360 Degree tour is the most expensive ever staged, but is also playing to larger crowds because they are performing in the round.

A string of younger pop stars - Britney Spears, Pink and the Jonas Brothers - came next on the list.

Coldplay were the most successful British group, at number eight, with takings of $27m (£18m).

Michael Jackson was the top earner from CD and ringtone royalties in 2009, but only made it to number 20 on the overall list, highlighting the importance of touring to a star's pay packet.