GroupM global boss Christian Juhl says rival holdcos may now regret spending “billions of dollars on cookie-based solutions or personally identifiable information” as privacy moves dead centre in regulatory affairs.. Some, he says, “are going to be sitting on a razor’s edge about whether they are going to be compliant ... it will definitely have ramifications for the industry.” In the meantime, he says a key challenge facing marketers across every facet of their business, and fundamentally “how they justify these massive budgets to their CEOs” comes down to measurement. But building post-privacy metrics and proxies, per Juhl, is probably the most “dynamic” – read challenging – part of his business. GroupM is building its own econometric or “full funnel” models for brands because, says ANZ CEO Aimee Buchanan, market mix models focused on shorter-term campaign metrics no longer cut it. Meanwhile, both Juhl and Buchanan have been pushing hard on carbon-based trading. Culling low performing, high emitting inventory is the easiest first step, says Buchanan, followed by stripping out digital weight from creative assets. But both bosses are less aggressive than previous statements around moving ad dollars based on emissions. Likewise, no hard mandates on getting staff back in the office beyond “probably more than we are right now,” per Juhl with hybrid flex built-in. For now, three days is a rule of thumb. Plus, Juhl is unsure how long brands will “pay more for less” on linear TV – and the world’s biggest media buyer thinks the world’s biggest streaming service, Netflix, has an opportunity to start integrating brands. Netflix’s Microsoft-powered ads launch may have underwhelmed, but Juhl sees “wide open” space ahead.