Spotify becomes world's 'richest start-up' with $4 bn valuation

Online music-streaming service Spotify has reportedly raised $250 million  in a new funding round, making it one of the world's most richly capitalized start-ups valuing it at more than $4 billion.

The extra funds can help the Swedish music service bolster its US business, as its net losses increased to $77 million  in 2012, Mashable reports.

Spotify reportedly doubled its revenues in 2012 to nearly $600 million with its growing popularity, but it continues to loose money by incurring losses.

Spotify previously raised $100 million , almost exactly a year ago, with a $3 billion  valuation, the report added.