The popularity of the Harry Potter series has translated into substantial financial success for Rowling, her publishers, and other Harry Potter related licence holders. This success has made Rowling the first and thus far only billionaire author. The books have sold more than 600 million copies worldwide and have also given rise to the popular film adaptations produced by Warner Bros. Pictures, all of which have been highly successful in their own right. The total revenue from the book sales is estimated, as of November 2018, to be around $7.7 billion. The first novel in the series, Harry Potter and the Philosopher's Stone, has sold in excess of 120 million copies, making it one of the bestselling books in history. The films have in turn spawned eight video games and have led to the licensing of more than 400 additional Harry Potter products. The Harry Potter brand has been estimated to be worth as much as $25 billion.
The great demand for Harry Potter novels motivated The New York Times to create a separate best-seller list for children's literature in 2000, just before the release of Harry Potter and the Goblet of Fire. By 24 June 2000, Rowling's novels had been on the list for 79 straight weeks; the first three novels were each on the hardcover best-seller list. On 12 April 2007, Barnes & Noble declared that Deathly Hallows had broken its pre-order record, with more than 500,000 copies pre-ordered through its site. For the release of Goblet of Fire, 9,000 FedEx trucks were used with no other purpose than to deliver the book. Together, Amazon.com and Barnes & Noble pre-sold more than 700,000 copies of the book. In the United States, the book's initial printing run was 3.8 million copies. This record statistic was broken by Harry Potter and the Order of the Phoenix, with 8.5 million, which was then shattered by Half-Blood Prince with 10.8 million copies. Within the first 24 hours of its release, 6.9 million copies of Prince were sold in the US; in the UK more than two million copies were sold on the first day. The initial US print run for Deathly Hallows was 12 million copies, and more than a million were pre-ordered through Amazon and Barnes & Noble.
Fans of the series were so eager for the latest instalment that bookstores around the world began holding events to coincide with the midnight release of the books, beginning with the 2000 publication of Harry Potter and the Goblet of Fire. The events, commonly featuring mock sorting, games, face painting, and other live entertainment have achieved popularity with Potter fans and have been highly successful in attracting fans and selling books with nearly nine million of the 10.8 million initial print copies of Harry Potter and the Half-Blood Prince sold in the first 24 hours. The final book in the series, Harry Potter and the Deathly Hallows became the fastest selling book in history, moving 11 million units in the first twenty-four hours of release. The book sold 2.7 million copies in the UK and 8.3 million in the US. The series was awarded the title of best selling children's book series by Guinness World Records in 2018. The series has also gathered adult fans, leading to the release of two editions of each Harry Potter book, identical in text but with one edition's cover artwork aimed at children and the other aimed at adults.
