In a strong pre-close update, housebuilder Persimmon revealed a 23% increase in full year revenues to £2.6bn and said it was confident of delivering strong growth in annual pre-tax profits and cash generation.The FTSE group, ahead of its unveiling of calendar 2014 results on 24 February, said that it saw "strong momentum" moving into the new year as houses had "sold well" right through to the end of the autumn season.The value of forward sales at the year end hit £973m, 7% ahead of the prior year and an impressive 40% higher than the £696m recorded at the beginning of November.Over the year, the number of completed new homes increased 17% to 13,509, with a 5% increase in average selling price to £190,500.This helped the York-headquartered group to remain confident of a further improvement in operating profit margins for the second half of the year, which it said "will underpin significant growth in pre-tax profits and excellent cash generation".Cash balances of roughly £378m at 31 December were higher than analysts had expected, with JPMorgan for example forecasting £290m, which left the possibility of a special dividend also being announced come results time.