Infosum CEO Brian Lesser is set to return to WPP to take on the top job at the network's investment arm, GroupM, following Christian Juhl's decision to step down from the Global CEO remit. Juhl will remain within the network, taking up a new position with WPP as President, Corporate Development.

Lesser previously spent 10 years with WPP, including as CEO of GroupM in North America from 2015 to 2017. He will rejoin WPP and begin his new role with GroupM in September 2024, until which Juhl will continue in his existing role to support the transition.

"It has been a privilege to lead this amazing business, to work alongside its incredibly talented people, and to partner with our wonderful clients around the world," said Juhl. "We've achieved a huge amount together and I'm really proud of the progress GroupM has made towards its mission of making advertising work better for people. After five years the time is right for a fresh challenge, and I'm excited to get started in my new role with WPP. Brian is an exceptional leader and I'm happy he is rejoining the GroupM family."

Lesser first joined WPP with the acquisition of 24/7 Real Media in 2007. During his time with the Holdco he founded Xaxis, the programmatic media buying platform which now forms part of GroupM's media performance organisation, GroupM Nexus. After leading GroupM in North America, Lesser joined AT&T as CEO of AT&T Advertising & Analytics, a $3 billion business today known as Xandr. Lesser took on his current role as CEO and Chairman of data company InfoSum in 2020.

"WPP and GroupM are special organisations to me. I have experienced first-hand the culture of innovation and collaboration that leads to exceptional work for advertisers. I am thrilled to be rejoining GroupM as Chief Executive Officer. I look forward to building with my talented colleagues, collaborating with our industry partners, and investing with our fantastic roster of global clients," said Lesser.

Juhl exits the CEO role after five years. He previously helmed Essence, the digital media agency acquired by WPP in 2015, and since merged to create EssenceMediacom. Under Juhl's leadership, GroupM has grown significantly, playing a critical role in WPP wins such as the partnership with The Coca-Cola Company. GroupM manages more than $60 billion in annual media spend on behalf of its clients.

CEO of WPP, Mark Read, said: "I would like to thank Christian for his contribution to the success of Essence, GroupM, WPP and our clients over the last nine years. He has built a strong foundation for the ongoing transformation of GroupM, the integration of its offer, and accelerated future growth. I look forward to working with him in his new WPP role. Brian is one of the industry's most highly regarded executives with a track record of success in data- and technology-driven marketing. GroupM, its agencies and its brilliant people are in many respects the engine of WPP. Brian not only knows GroupM inside-out, but also has a strong vision for the future of the business. We are delighted to welcome him back to WPP."