Stockholm-based online music-streaming service Spotify has raised $250 million in a new funding round, making it one of the world’s most richly capitalized start-ups, according to Wall Street Journal.

The round of funding, led by Silicon Valley firm Technology Crossover Ventures, will help fuel Spotify’s global expansion plans and bolster its U.S. business, which trails services such as Pandora, and launch in other countries such as Japan.

The newest financing brings the value of Spotify to more than $4 billion, according to the Wall Street Journal.

Just a handful of start-ups, including daily deals site Living Social, online bulletin board Pinterest and online survey tool SurveyMonkey, have raised more than $400 million, Reuters said.

A Spotify spokesman declined to comment.

In March, Spotify said it had surpassed 6 million subscribers, a gain of 1 million since December, making it the fastest-growing digital music company ever and second in reach to Pandora.