J K ROWLING'S autograph has become one of the most sought-after in the world and is out- selling those of superstars such as boxing legend Muhammad Ali and the late pop star Michael Jackson.
The Edinburgh-based author has made it on to a list of the world's most valuable autographs compiled by memorabilia specialist Paul Fraser Collectibles.
Her signature is also worth more than those of Madonna, Beatles drummer Ringo Starr and artist Salvador Dali.
Investors have been urged to seek out signed copies of books by the multi-millionairess Harry Potter author as they are a more lucrative bet than stocks and shares.
The new research has shown that her signature has increased in value from 395 to 1,200 over the past ten years, a rise of 204 per cent.
Memorabilia experts predict its worth will continue to rocket in future years as copies become more rare.
A photograph signed by all four members of the Beatles is 2010's most valuable autographed item at 22,500, a rise of 17,000 from its price ten years ago.
Paul Fraser, an expert in high-end collectible items, said: "The Boy Wizard is a proven global phenomenon and there isn't enough JK Rowling memorabilia to meet demand.
"Harry Potter is the highest- grossing film series of all time, with $5.4 billion worldwide receipts.
"More than 450 million Harry Potter books have been sold, with the books printed in 67 different countries. Signed books are an area of increasing demand and the real price rises are sure to come in ten years time when today's hardcore fans have the disposable income to invest in their childhood interest.
"Rowling's signature is a perfect opportunity for entry-level investors.
"It was worth just 395 back in the year 2000. Today, its value is closer to 1,200. What's more, as the Harry Potter film franchise steadily draws to a close and its stars and Rowling move on to other things, its value will only continue to grow.
"A particularly good Rowling autograph to look out for is her signature - ideally alongside an inscription - on the book which started it all, Harry Potter and the Philosopher's Stone."
US president Barack Obama asked for Rowling's autograph as a present for his daughters after he met her at a Downing Street reception last year. The writer, who is worth more than 500m, has warned fans to beware of fake autographs being sold on online auction site eBay. She said that for every genuine signature on the site, there were ten fakes.
The index was compiled by comparing auction bids for autographs from all over the world.
l The trustee of the estate of late English author Adrian Jacobs is considering filing a lawsuit in New York against Harry Potter's US publisher for infringement of copyright.
The estate claims JK Rowling copied a substantial part of Jacobs' 1987 book The Adventures of Willy The Wizard No 1 Livid Land into her book Harry Potter and The Goblet of Fire published 13 years later by Scholastic.