Bloomsbury Publishing is shifting its affections from Harry Potter to the Sage of Omaha. The book publisher, which reported strong first-half financial results on Friday, said Alice Schroeder’s authorised biography of Warren Buffett, The Snowball, would be “one of the most important books of the year” when published next month.

Results for the six months to 30 June were ahead of analysts’ expectations, thanks to strong sales in UK adult and specialist books.