When it announced its plans to acquire Interpublic Group of Cos. on Monday, Omnicom Group also provided some details about the proposed company, including its leadership and (not so) new name, Omnicom. There are still plenty of unknowns about the combined entity, which is poised to dethrone WPP as the world’s largest agency group.

For starters, there are the many agency brands that will be brought together. In an investor call about the acquisition, Omnicom and IPG executives said there hasn’t been any immediate decision on how the company will structure its agencies, should the deal pass regulatory approval. Some analysts, however, have offered their thoughts.

More: What the proposed merger means for the industry
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“Mediabrands will likely roll up to Omnicom Media Group, IPG creative companies will join the Omnicom Advertising Group and Acxiom will likely be aligned with the technology group managing Omni,” said Jay Pattisall, VP and principal analyst at Forrester.

And then there’s the personnel. Though Omnicom Chairman and CEO John Wren said that staffers tied to revenue-generating business would be safe (“You’re gold,” Wren said of such employees on the call), layoffs are expected to follow the deal. 

Ad Age can’t presume to know what the new Omnicom will look like should the deal close in the second half of 2025, but here are several Omnicom and IPG executives who appear poised to play decisive roles at the proposed advertising behemoth, listed in alphabetical order.

Alex Hesz, global chief strategy officer at IPG

Integration is going to be crucial to the holding company’s success. Wren even mentioned during the investor call that a key factor of the merger is how many executives have shared experience between both holding companies.

“In the recent past, Omnicom and IPG agencies have worked well together,” Donna Sharp, managing director of MediaLink, said. “We see them being true partners to the client, and that means being able to look past the logos they represent … better than some of the other competition.”

Alex Hesz might be a key executive in this merger given he was also previously a chief strategy officer for Omnicom. Prior to that role, he was a global chief strategy officer at Omnicom’s DDB, one of the company’s most well-known creative agencies.

Jacki Kelley, executive VP, chief client officer and chief business officer at IPG

Jacki Kelley joined IPG as its executive VP, chief client officer and chief business officer in June 2023. She came from Dentsu, where she served as its Americas CEO. Prior to that, she was North America CEO and president of global clients at IPG Mediabrands. 

Kelley has been positioned as helping define the future of IPG’s new business strategy while managing existing and new client relationships, according to multiple people close to the situation. With her multiple holding company-level experiences, Kelley is poised to retain a high-level position post-merger.

Florian Adamski, CEO of OMG, and Eileen Kiernan, global CEO of IPG Mediabrands

Both Eileen Kiernan and Florian Adamski are worth monitoring given the Omnicom-IPG deal’s focus on media scale. If Mediabrands is folded within OMG, it will be interesting to see what becomes of Kiernan, who formerly spent more than a decade at IPG’s UM, culminating in a stint as global CEO. 

Adamski implemented Omnicom’s “Agency as a Platform” in 2022, with hopes of giving clients more flexibility by providing customized solutions. He succeeded Daryl Simm in the top role at OMG.

Philippe Krakowsky, CEO of IPG

Philippe Krakowsky’s days leading IPG are coming to an end.

If the deal closes, Krakowsky will serve as co-president and co-chief operating officer of Omnicom alongside Daryl Simm. Krakowsky will also be co-chair of the integration committee post-merger and sit on Omnicom’s board of directors. 

The appointment suggests a theoretical battle between Krakowsky and Simm to succeed Wren, though it’s unlikely the former would assume the top role again. As one former Omnicom executive told Ad Age on Sunday, the deal gives Krakowsky “the exit plan he’s been looking for.”

Daryl Lee, global CEO of McCann Worldgroup

While IPG’s biggest creativity network, McCann Worldgroup, has lost some major clients recently, such as Verizon and a reduction in scope from General Motors, it’s still worth watching—with clients including L’Oréal and Mastercard. Daryl Lee, who took over as McCann Worldgroup’s global CEO in 2022, will be pivotal in deciding the future of one of the most historic agencies left in the industry.

Lee also brings expertise from the other side of the coin. He previously served as the global CEO of IPG Mediabrands and before that the global CEO of UM. In total, he has spent nearly two decades with IPG.

Sergio Lopez, CEO of Omnicom Production

In June, Omnicom consolidated its production capabilities under one entity called Omnicom Production, which Sergio Lopez leads as CEO. As AI becomes more prevalent in the advertising industry, fast content at scale has become a larger ask for clients and has put a bigger target on production companies to perform.

MediaLink’s Sharp said Omnicom has been showing up “very strongly in production-specific reviews.” 

Dana Maiman, CEO IPG Health

Health has been a strong point for IPG despite recent struggles, even despite losing a large slice of the Pfizer account in March. Omnicom and IPG said the combined company’s largest industry would be pharmaceuticals and health care, representing 19% of combined revenue and potentially opening up an expanded role for Dana Maiman.

Maiman oversaw the launch of IPG Health in 2021, when IPG combined FCB Health and McCann Health under one roof.

Jarrod Martin, global CEO of Acxiom and Kinesso

In June, IPG gave Kinesso Global CEO Jarrod Martin oversight of Acxiom, which Wren and Krakowsky both highlighted as a pivotal focus for the new Omnicom. Martin is now also overseeing Mumbai-based retail analytics company Intelligence Node, which IPG acquired last week and folded into Kinesso.

Martin began his career at IPG in 2013, where he started a specialist analytics unit in Australia. He later moved to New York, where he became global COO of IPG Mediabrand’s Initiative.

Duncan Painter, CEO of Omnicom’s Flywheel

Flywheel, the digital commerce company Omnicom shelled out $835 million for in October 2023, is a crucial component of the Omnicom-IPG deal. During the investor call, Krakowsky emphasized that Omnicom aims to cross-sell Flywheel with IPG’s Acxiom, which uses first-party data. 

Duncan Painter took the helm of Flywheel after the Omnicom deal—and multiple industry insiders highlighted the executive as one to watch following the IPG deal. He previously served as CEO of Ascential, a business-to-business company that owns Cannes Lions.

Nancy Reyes, global president and CEO of BBDO

BBDO, one of Omnicom’s creative crown jewels, has made several organizational changes in 2024, including consolidating leadership for its New York and Chicago offices. Now, Global CEO Nancy Reyes will have to figure out BBDO’s place in a much broader creative engine, one that would include IPG’s FCB, Deutsch and McCann.

Reyes is the first woman and person of color to hold the global CEO role at BBDO. Before her August promotion, she was BBDO’s Americas CEO.

Troy Ruhanen, CEO of Omnicom Advertising Group

Some industry experts believe the new Omnicom will further consolidate its many creative agencies, many of which are “struggling to maintain profitability and facing disruption from AI,” along with needing to move beyond traditional ‘time and materials’ business models, according to Tom Denford, CEO of ID Comms.

Those creative agencies, including McCann, TBWA and The Martin Agency, would be under the purview of Troy Ruhanen, who in August was named CEO of Omnicom Advertising Group. Ruhanen was formerly CEO of TBWA Worldwide.

Daryl Simm, president and COO at Omnicom

In 2021, Omnicom appointed Daryl Simm as its president and chief operating officer. At the time of his appointment, it was reported that Simm was a likely successor to Wren. He was the first president appointed since Wren was elevated to chairman in 2018.

Prior to his current role, Simm served as the CEO of OMG for more than two decades. Following the merger, Simm will serve as co-president and co-COO alongside Krakowsky.

John Wren, chairman and CEO of Omnicom

Wren is staying on as Omnicom’s chairman and CEO after striking another deal to establish the world’s largest agency group, following a failed attempt to merge Omnicom with Publicis Groupe in 2014. It will be worth monitoring how long he stays at the helm.

Under Omnicom’s “mandatory retirement age policy” for board members, Wren, 72, would need to retire from the board no later than 2028, the year after he turns 75. However, the Omnicom board “may waive this limitation for any director if the board determines that it is in the best interests of the company and its shareholders to extend the director’s service.”

Wren has been CEO since 1997 and board chairman and CEO since 2018. According to a 2021 SEC filing, Wren’s employment with Omnicom was slated until Dec. 31, 2024, with automatic renewals every year thereafter, “unless either party timely notifies the other of their intent not to renew the Employment Agreement.”

Paolo Yuvienco, chief technology officer of Omnicom

Paolo Yuvienco has been responsible for building Omni—Omnicom’s homegrown data and analytics platform—which the holding company plans to bolster with assets from IPG. As well as fine-tuning Omni, Yuvienco also created a framework for how it integrates within Omnicom.

Yuvienco, who joined Omnicom in 2017, also led the creation of its ArtBotAI in July, and was a key advisor in Omnicom’s acquisition of Flywheel.