Last year’s deal in which WPP’s Xaxis programmatic unit divested its ad-serving technology to ad tech outfit AppNexus was forged in the snowy hills of the Swiss Alps.

“For five years, we had a good relationship,” AppNexus CEO Brian O’Kelley tells Beet.TV in this video interview. “Last January in Davos, I found 15 minutes with Martin Sorrel and said, ‘Martin, you really need to take this incredible asset that Xaxis has in open ad stream and combine it with all the tech that AppNexus has so that an can be the best ad technology business out there…’.

Under the deal, WPP put $25 million in to AppNexus but gave it control of its Open AdStream technology, rebadged “Xaxis For Publishers”. It was about giving AppNexus control of one specific piece of its offering.

“I see it as a perfect complementary relationship…,” O’Kelley adds. It’s critical to our future and I think it’s pretty important to Xaxis as well.”