1. Leidos

Coming in at the No. 1 spot with an astronomical growth rate of 82.1 percent year over year was Leidos. The company reported cybersecurity consulting revenues of $285 million in 2016, up from $157 million the year before. Gartner said a significant portion of that growth came from the company's merger with Lockheed Martin's Information Systems & Global Solutions business, a deal completed in August 2016.