Uber has unveiled the terms of a hotly anticipated stock market float which it hopes will value the ride-hailing service at more than $91bn (£70bn). While the target is $10bn less than some bankers suggested the 10-year-old firm might be worth, the valuation is more than double the value of the 116-year-old carmaker Ford and would be the largest float by a US tech company since Facebook's in 2012. Its Wall Street debut will gauge investors' excitement about the prospects of a company that has expanded rapidly from taxi services into food delivery and is now investing billions in developing driverless cars. If it hits the mark, Uber will raise around $9bn in new funds and some early investors will make big profits. Despite the scale of ts ambition, Uber lost $1.8bn last year even while its revenues surged by more than 40% to $11.3bn.