Allen & Overy (A&O), Paul Hastings, and Weil Gotshal & Manges are advising as British advertising giant WPP sells a majority stake in its data arm to U.S. private equity firm Bain Capital in a multibillion-dollar deal.

WPP has agreed to sell a 60% stake in its data analytics branch Kantar to Bain in a deal that values Kantar at about $4 billion.