‘Harry Potter’ Production Accounts Reveal Clue About Budget For HBO Series

Harry Potter is on course to be among the most expensive series ever made by HBO.

A source familiar with the adaptation of J.K. Rowling’s beloved books confirmed that the Potter series will rank alongside the final season of Game of Thrones and The Last of Us, as production accounts provided a clue about the show’s budget.

Harry Potter is being produced in the UK through the special purpose vehicle company Plum Jam Productions, which recently filed earnings for 2025 on the UK’s Companies House.

The accounts showed that Plum Jam Productions’ revenue was £130.6 million ($175M) last year, when Season 1 of Harry Potter first went into production at Warner Bros. Studios Leavesden. The company’s revenue was £18.4M in 2024, when development got underway on the show.

The figures suggest that as much as £150M ($201M) could have been spent embarking on the Harry Potter television project, which is aiming to retell each of Rowling’s seven books one season at a time.

The Plum Jam Productions sales figures are unlikely to be a complete picture, however, and the company has been used to house other productions in the past, meaning its earnings could theoretically include non-Potter-related income. Plum Jam used to be called Roundabout Productions, which was the vehicle through which The Nevers was produced.

Taking Plum Jam Productions’ earnings as a rough guide, Harry Potter‘s first season could average out at around £18.8M ($25.2M) per episode. Though an estimate, it would mean that Potter comfortably sits in the same big-budget bracket as the final season of Game of Thrones, which was widely reported to have cost $15M an episode.

A source familiar with the Harry Potter series said the cost of making the drama is front-loaded because the lavish sets built at Warner Bros. Studios Leavesden should serve all seven seasons. This will likely mean that the average budget of future Harry Potter episodes will drop.

HBO declined to comment. The Times of London first reported on Plum Jam Productions’ earnings.

Harry Potter will premiere in December on HBO, with a cast that includes Dominic McLaughlin, Alastair Stout, and Arabella Stanton as Harry Potter, Ron Weasley, and Hermione Granger.

Other major cast members include John Lithgow as Hogwarts’ headmaster Albus Dumbledore; Paapa Essiedu as Severus Snape; Janet McTeer as Minerva McGonagall; Nick Frost as Rubeus Hagrid; and Bel Powley and Daniel Rigby as Harry’s Aunt Petunia and Uncle Vernon Dursley.