Facebook has set the initial target stock price for its IPO on 18 May, aiming for between $28 and $35 per share, which would value the company at between $77bn and $96bn. That means the social network could raise as much as $13.6bn by going public - a move that would value CEO Mark Zuckerberg’s stake at up to $18.7bn. And this is just the initial price: once the IPO happens, the valuation of the company will be up to investors. Alongside the pricing announcement, Facebook has revealed some more stats about the advertising side of its business. The social network makes $9.51 in ad revenues for every user in the US and Canada, versus $4.86 in Europe, $1.79 in Asia and $1.42 in the rest of the world - an average ad revenue per user of $4.34 globally. With more than 900m monthly active users, Facebook gets 85% of its revenues from advertising - and this is before turning ads on for its 500m+ mobile users.