The Harry Potter series is far and away the highest-selling series of novels ever. Written by British author J.K. Rowling, the series has sold at least 500 million copies.
The highest-selling book in the series, Harry Potter and the Sorcerer’s Stone, sold 120 million copies alone.1 Even more impressive than the series’ sales dominance is the relatively few number of novels in the series—there are only seven Harry Potter books. The Goosebumps series, in comparison, includes 62 main installments.
While originally a book series, the Harry Potter franchise has grown into a worldwide brand, with movies, theme parks, video games, plays, and toys all based on Rowling’s Wizarding World. The Harry Potter movies are some of the highest-grossing of all-time, and the play set in the universe was a relative financial success on Broadway.
According to investopedia.com