GroupM's audience buying unit Xaxis is able to create private exchanges online for premium publishers, says Christina Beaumier, VP of Global Client Development in this interview with Beet.TV

Beet.TV contributor Ashley Swartz interviewed Beaumier about the inner workings of audience buying in this fashion at the recent Beet.TV Leadership Summit on Digital Video Advertising in an RTB World.

"We go to our biggest advertisers and collect all of their spend and then go to to publishers that otherwise don't put their inventory on an exchange, and that allows us to do programmatic buying on those exchanges," she explains to Beet.TV in this interview.

That approach gives brands access to premium inventory but with the benefits of audience buying, she says. "They're only delivering impressions and brand messages against the users who matter and they're doing it in a very efficient way."

The benefit to publishers lies in transparency and a controlled manner of making their inventory accessible via an open real-time buying marketplace, she says. In some markets, more than 50% of the inventory available through this premium marketplace is video.

This Beet event took place at the Manhattan offices of GroupM and was presented by TubeMogul.

Daisy Whitney