Harry Potter publisher Bloomsbury reported a strong set of results for the first half of the year, after a star performance from ebooks. The mid cap publisher reported phenomenal ebook sales growth, up 564% to £2.5m. ebook sales represent 5.5% of total group sales."2011 remains the year of the ebook...Our early-mover advantage and the investment we have made, means we are well positioned to benefit from continued digital growth."Group pre-tax profit, adjusted for highlighted items, rose to £2.2m for the six months ended 31 August 2011 from £1.4m in 2010. Turnover was up 16% to £44.9m in the half year period. Pre-tax profit slipped to £0.3m compared to £0.8m.The group, which splashed out £20.1m on US academic specialist Continuum earlier this summer, underlined its confidence in future trading by increasing its interim dividend payment by 10% to 0.89p.Bloomsbury said it was making good progress in integrating the Continuum business into Bloomsbury and is on track to deliver expected synergies. The Continuum acquisition marked Bloomsbury's continued move away from the more volatile retail market. "Our Academic & Professional division was bolstered by the transforming acquisition of Continuum in July, providing us with more stable and predictable income streams," the group said in a statement.Chief executive Nigel Newton said markets in both the UK and US are performing above expectations with a robust second quarter following a slow first quarter.Newton also issued a confident outlook for the restructured business which, "combined with continuing ebook growth and our strong content, will enable us to deliver results in line with our expectations." --cj