BlackBerry Z10 and iPhone 5 smartphones

Half a decade ago, as companies across the globe started ditching BlackBerry devices for iPhones, chief information officers were stuck in a bind. All the servers and security tools they'd purchased over the years were dedicated to those once-dominant BlackBerry e-mailers, and wouldn't work with the new wave of app-heavy—and non-BlackBerry—smartphones.

MobileIron was among a handful of start-ups that saw big bucks in the emerging bring-your-own-device movement. Rather than waiting for Apple and eventually Google and Samsung to focus their attention on back-end protection, businesses could buy MobileIron's software to help them manage and secure the vast array of touch-screen phones and eventually tablets that employees were favoring.