The former Wexford primary school teacher has sold over 25 million books — translated into 44 languages — charting the adventures of his teenage criminal mastermind, Artemis Fowl.
Newly-filed accounts for Mr Colfer’s firm, Artemis Fowl Ltd, show accumulated profits last year jumped by just under €395,000 to €3m.
This followed an €800,000 increase in 2014. The firm’s cash pile fell from €2.6m to €1.68m last year, on account of Mr Colfer investing over €1.1m in financial assets.
Mr Colfer is listed as director of the company with his wife, Jackie and the accounts show their combined pay last year decreased from €150,791 to €101,620.
Last year, Mr Colfer won the prestigious commission from Marvel Comics to write a new instalment of the ‘Iron Man’ comic book series, with it due to be released in October.
He has set the book in Ireland with the ‘Iron Man’/Tony Stark character attending an international eco-summit in Dublin.
In 2013, Disney added to Mr Colfer’s coffers when they confirmed that the adventures of Artemis Fowl are to be made into a movie with Robert de Niro lined up as executive producer.
One of the most influential figures in cinema, Harvey Weinstein will also produce.
The film will cover the first two books of the series. Mr Colfer - who celebrated his 51st birthday in May of this year - published the eighth and final book in the best-selling Artemis Fowl series in 2012.