Hacker posts Harry Potter's alleged ending on Web

"We've had hypes like this on the last couple of Harry Potter books," he said. "There is a very high level of spurious information in the hacker world."

But if true, it could be a problem for Bloomsbury. The "Harry Potter" books have been global best-sellers with fans buying some 320 million versions worldwide, and anticipation for "Deathly Hallows" is high.

In April, U.S. retailer Barnes & Noble said advance orders for the book had already topped 500,000 copies, setting a chain record. Scholastic plans to release a record 12 million copies of "Deathly Hallows" to meet demand.

A stolen copy of the sixth Harry Potter novel, "Harry Potter and the Half-Blood Prince" surfaced in Britain about a month before its official release in July 2005. Two people were charged after reportedly trying to sell a copy to the London tabloid the Sun.

Four "Potter" movies made by Warner Bros. film studio, a division of Time Warner Inc., have brought in $3.5 billion in global ticket sales, and a fifth film is due in theaters in early July.

(Additional reporting by Bob Tourtellotte in Los Angeles and Kate Holton in London.)