An independent study has claimed that Apple's iTunes has overtaken Wal-Mart as the largest music retailer in the US.
Market research firm NPD said that iTunes surpassed Wal-Mart during January and February of this year, if 12 downloads are considered the same as a buying one album.
Apple, which makes iPod media players, Macintosh computers and the iPhone said in a statement that iTunes now had 50 million customers who had bought more than four billion songs since the service became available five years ago.
Eddy Cue, iTunes vice president, said: "We are thrilled, and would like to thank all of our customers for helping us reach this incredible milestone.
"We launched iTunes less than five years ago, and it has now become the number one music retailer in the world."
Rolling Stone magazine claimed the new figures showed the big transformation in the music business since the development of downloading music.
A major new rival to iTunes however was unveiled on Thursday, the same day as Apple announced it had become the number one music supplier in the US.
New Corp's MySpace social networking website announced that it has formed an online music venture with three major record labels Universal, Sony BMG and Warner.