J.K. Rowling's magic touch sends 'Harry Potter' book sales booming

J.K. Rowling turned her creative focus back to the popular world of Harry Potter last year and the results were stunning. Sales of the seven-book series, which concluded in July, 2007, nearly doubled last year in the United States.

New Potter material has been in short supply since the eighth and final Hollywood movie came out at the end of 2010. After selling over 1.5 million print books a year in 2010 and 2011, series sales in the U.S. declined to an average of under 800,000 a year from 2012 through 2014, according to data from Nielsen Bookscan.

But in June, Rowling had a huge surprise for the 6 million Potter fans who follow her on Twitter: She was back at work on a play about the boy wizard and his two best friends from the the Hogwarts School of Witchcraft and Wizardry, Hermione Granger and Ron Weasley.

I'm also very excited to confirm today that a new play called Harry Potter and the #CursedChild will be opening in London next year.

— J.K. Rowling (@jk_rowling) June 26, 2015

Rowling later disclosed that she was collaborating with British playwright Jack Thorne on a new stage drama, "Harry Potter and the Cursed Child," to carry the adventures of the childhood trio into adulthood. The play, in two parts, will open in London this summer. Excitement grew last month when lead casting was announced, including black actress Noma Dumezweni as Hermoine.

And a prequel movie, "Fantastic Beasts and Where to Find Them," which had been loosely in the works for several years, got a star, Eddie Redmayne, and an official trailer (which has been viewed 10 million times on YouTube).

Finally, just in time for the holidays and capitalizing on a recent spurt of sales in coloring books for adults, Rowling released several fill-between-the-lines Harry Potter issues with illustrations from images used to create the eight movies.

The result was not just an explosion of interest on social media and best-selling coloring books, but also a revival of sales of the original series to 1.34 million copies in 2015, up 63% from the year before, according to Nielsen Bookscan. Add in another 220,000 coloring books sold and the total exceeds 1.5 million books. Nielsen gets reports from retailers covering 85% of the print trade book market, including Amazon (AMZN) and Barnes & Noble (BKS).

"Harry Potter continues to attract new generations of readers and is a top franchise for Scholastic," Kyle Good, spokesman for the U.S. publisher (SCHL), said.

Scholastic said it had sold 150 million U.S. copies of the series through 2013, but declined to update the figure. British publisher Bloomsbury, which said in 2013 a total of 450 million copies had been sold worldwide, did not respond to a request for comment.

Rowling has always left open the door to write more Potter tales after famously completing the last book, "Harry Potter and the Deathly Hallows," in a room at the Balmoral Hotel in Edinburgh in January 2007. In 2010, she told Oprah Winfrey she could "definitely write an eighth, ninth, 10th book," adding, "I think I am done but you never know."

Last year's boom in Harry Potter book sales came even as Rowling and her team revamped her groundbreaking web site, Pottermore, launched in 2012 as the official home for fans of the series and the exclusive seller of Harry Potter ebooks and digital audio books. At the time, some thought the author's efforts to sell directly to fans might provide a model to best-selling authors around the world. But few of Rowling's peers had the market power to convince Amazon and Barnes & Noble to open their ebook gates and allow someone else to act as an exclusive front-end for digital sales.

Beginning last fall, Pottermore phased out the ebook and digital audio exclusives. Other ebook retailers were allowed to sell Harry Potter books directly to consumers, starting with Apple's iBooks store in October and Amazon's Audible store in November. Currently, the ebooks are available on more than a dozen retailers' sites.

That changes -- along with disclosure of financial data covering the year ended March 31, 2015 -- led to negative press about the results at Pottermore. Sales dropped to 7 million pounds ($9.9 million) for that year from 32 million pounds the year before, leading to a small net loss, and the number of employees decreased 25% to 30 people, the Scotsman newspaper reported on Jan. 17.

While the figures from Nielsen Bookscan include only U.S. print books, Pottermore executives said their change in strategy at the site also boosted digital sales signficantly.

"Our business is healthy, viable and well-positioned to capitalise on the massive global interest in the Harry Potter franchise and J.K. Rowling’s Wizarding World,” Pottermore CEO Susan Jurevics said in a statement.

The site broke its monthly sales record in December 2015 with "an unprecedented number" of ebook and digital audio book downloads, Jurevics said.

The Potter ebooks shot to the top of the sales charts on iBooks in October and several digital audio books have been on the top 10 list at Amazon's Audible store since November. Headcount at the site is back up to 40 people, a spokesman said.

The site's sales may wax and wane from year to year but the strategy of collecting contact information and keeping a relationship going with fans is smart, says publishing industry consultant Mike Shatzkin. "Just wait for the original fans to start having kids -- they can start all over with a new generation," he says.