According the the Forbes website;
"Immortal vampire and small-town doctor has quietly amassed a fortune over the centuries. In 1670 received generous handout from Italian friends; put savings in bank, reaped billions in compound interest. Made shrewd long-term investments in steel, gold, oil, thanks to prescience of daughter turned financial advisor Alice; saw recessions coming, invested early in Wal-Mart. Earned doctor's salary for 340 years without paying for groceries, health care expenses. Avoids sunshine and public displays of wealth but owns several valuable properties, including yacht, private island, collection of Renaissance art."
Read all about him and his family in the Twilight series by Stephanie Meyer.
Also making it onto the list are comic book stars Tony Stark (from the Iron Man series) at No.4, at No.6 Adrian Veidt aka "Ozymandias" (from Watchmen) and Bruce Wayne (from Batman series) at No. 7.
Artemis Fowl II makes it in at number 11 with $1.9 billion (from inheritance, theft and technology patents). Son of an Irish crime lord he took over the family business and is trying to make it legal. You can read all about him in the books written by Eoin Colfer.
The mysterious billionaire Jay Gatsby (right) just squeezes in at number 14 - this self-made man is famed for his weekend long parties and extensive clothing collection. Find out more about him the 'The Great Gatsby' by F. Scott Fitzgerald.
Read the full list here.
