MediaMath built one of the industry's first demand-side platforms, which allow advertisers to target online display ads across the web in real time. Along the way, it built a services team that operated much like a media agency, so much so that it's spinning that unit out into a new media agency called Kepler Group.

Nine of MediaMath's current clients will become Kepler Group clients, including Kayak, the travel search company. Most of these advertisers will continue to license technology directly from MediaMath and use Kepler to plan, execute, optimize and provide analytics on their campaigns. Kepler will focus on display advertising to start, but will get into other digital channels as clients ask for it.

MediaMath will hold a minority stake in the six-person startup, which will be run by Rick Greenberg, formerly MediaMath's SVP and head of sales in the Americas.