Dropbox has positioned itself as the most valuable of the latest crop of Silicon Valley companies raising what are likely to be its last new funds before it goes go public, with a deal that prices the cloud storage provider at $10 billion (€7.3 billion).

A fund managed by BlackRock, the world's largest asset manager, led a $250 million investment in Dropbox, according to a source familiar with the situation, capping another week of soaring valuations for California tech companies.

Dropbox began discussions about its fundraising in November, when a price tag of $8 billion was discussed, suggesting that competition for the deal – or for access to fast-growing private technology companies – intensified over the subsequent weeks.

Its earlier 2011 fundraising valued the company, founded almost seven years ago by Drew Houston and Arash Ferdowsi, at $4 billion, when Goldman Sachs led a $250 million investment. Dropbox, which once turned down a takeover offer from Steve Jobs at Apple, allows its more than 200 million active users to store documents, photos and other files in its cloud, ensuring they can access the same data from several devices. Most use the service for free but some pay $10 a month to increase the storage allowance.

Facing growing competition from the likes of Box for corporate users, Dropbox has increased its enterprise capabilities, but selling to large companies often requires a larger salesforce.

The latest investment is likely to pour fuel on the debate about the rationality of valuations applied to Silicon Valley companies. People familiar with Dropbox's finances told the Financial Times last year its 2012 revenue was about $110 million. Since then, its user numbers have doubled but a $10 billion valuation builds in high expectations for even further growth. – (Copyright The Financial Times Limited 2014)