Rich list reveals JK Rowling's Potter gold

Harry Potter author J.K. Rowling has joined the ranks of the world's ultra-rich and is now estimated to be worth £526 million ($NZ1.4 billion).

Rowling has made her debut on the Forbes magazine's billionaires list at number 552.

For the 10th year running Microsoft founder Bill Gates tops the overall list with a net fortune of US$46.6 billion.

The 18th list sees the ultra-rich getting even richer, and more numerous. The collective net worth of the those on the list has leapt half a trillion dollars to $US1.9 trillion, while there were 64 new entries this year.