Brian Lesser knows who you are. Well, not exactly — not by name or face. But as the North American CEO of GroupM, the world’s biggest media-buying firm, he has a central role in deciding what television commercials, banner ads, and other marketing messages you’ll see, and when you’ll see them. He does it with a wealth of data — on your demographic profile, your purchasing habits, your browsing history, and your location at any given time. If you see an ad offering exactly what you want to buy, at exactly the moment you want it, you likely have Lesser to thank.
In 2011, Lesser started a company within GroupM called Xaxis, which processes all of that data and figures out how best to target individuals with the right ads at the right time. In five years, he built it to a $1.2 billion annual business. Late last year, WPP — GroupM’s parent and the world’s largest advertising holding company — promoted Lesser to his current job. Today, he oversees six media agencies and specialist companies within GroupM that handle $27 billion in annual ad spending for its clients, or 25 percent of the North American market. (Globally, GroupM controls $103 billion in annual ad spending and accounts for one in three ads worldwide.) Lesser spoke to Traffic in July from a surprisingly nondescript office in GroupM’s to-be-vacated midtown Manhattan headquarters — in two years they’ll be moving downtown, as the anchor tenant of 3 World Trade Center.