THE rapid rise of digital music sales has stalled in the United States, the world's biggest and most important market, with sales in the first half of 2010 flat versus a year before.

According to research group Nielsen, digital sales were flat in the US market after a 13 percent increase from 2008 to 2009 and 28 percent growth from 2007 to 2008.

Major music companies such as Vivendi's Universal Music have pinned their hopes on boosting legal digital sales to counter online piracy and the collapse in CD sales.

Jean Littolff, managing director of Nielsen Music, said the flat US sales could be due to weak consumer mood, the appeal of new music releases and confusion over the different ways one can buy music online. "I think this is a plateau, but it's not yet saturation," he said.