Dropbox files for IPO as other 'unicorns' watch

Dropbox will be especially scrutinised after the fizzling of other buzzy tech start-ups that went public last year

In Silicon Valley and on Wall Street, it has long been a guessing game about which of the most richly valued technology start-ups would be next to test the public markets.

On Friday, there was an answer: Dropbox, an online file storage company privately valued at about $10 billion, filed paperwork to raise up to $500 million in an initial public offering.

While Dropbox may not have the glamour of a ride-hailing app like Uber or a streaming music service like Spotify — both of which are likely initial public offering prospects — the company is in the same broad group known