SAN FRANCISCO (AFP) - Home sharing giant Airbnb just raised $555 million (S$751.1 million) and is seeking even more in a funding round that values the company at US$30 billion, a source close to the company told AFP.

The startup has taken in US$555.46 million through a private funding round that launched in late July and remained open, according to a filing by the company on Thursday (Sept 22) with the US Securities and Exchange Commission.

The funding round could reach US$850 million, the source told AFP.

Money taken was expected to be used to fuel growth and international expansion of Airbnb.

An investment arm of internet titan Google and Technology Crossover Ventures were among backers taking part in the funding round, according to the source.

A value of US$30 billion - based on what stake in the company investors get for their money - makes Airbnb the most valuable Silicon Valley startup behind ride-sharing titan Uber, which has been reportedly valued at US$68 billion.

Airbnb had a value of US$25.5 billion during a US$100 million funding round in November 2015.

The San Francisco-based company, run by co-founder Brian Chesky, hoped to begin showing a profit this fiscal year.