It’s official: Omnicom Group has agreed to acquire Interpublic Group of Cos., the companies confirmed today, in a deal that creates the world’s largest agency group. 

The combined entity, which will have more than 100,000 employees, will retain the Omnicom name and trade under the OMC ticker on the New York Stock Exchange, according to a statement from both companies. The all-stock deal is expected to close in the second half of 2025 and generate $750 million in annual cost synergies.

More on the news:

• What the proposed merger means for the industry
• Indie creative agencies react to the Omnicom-IPG deal
• What the pending acquisition means for clients
• How the deal hinges on data and automation
• Key executives to watch
• How Omnicom-IPG would stack up against the industry

John Wren will remain chairman and CEO of Omnicom, and Phil Angelastro will continue as chief financial officer. IPG CEO Philippe Krakowsky and Omnicom Chief Operating Officer Daryl Simm will serve as co-presidents and COOs of Omnicom. Krakowsky will also be co-chair of the integration committee post-merger and sit on Omnicom’s board of directors, along with two other members of IPG’s board.

Omnicom and IPG had combined revenue of $25.6 billion in 2023, according to the companies.

“This strategic acquisition creates significant value for both sets of shareholders by combining world-class, highly complementary data and technology platforms enabling new offerings to better serve our clients and drive growth,” Wren said in a statement.

During an investor call held to discuss the announcement, Wren said he and Krakowsky started talking about a potential deal roughly a year ago. Both executives downplayed potential client conflicts stemming from the deal, claiming that marketers aren’t as concerned with such issues anymore.

“I’m not aware or threatened by any conflict as a result of us announcing that we’re joining forces,” said Wren. Moving forward, Omnicom and IPG need to assure its clients “that we still love them quite as much as we did prior to this morning,” he added.

Investors’ initial reaction to the deal was negative, with Omnicom’s shares tumbling more than 6% this morning in early trading.

Omnicom shares were trading around $97 early today, which is well below their all-time high of $107 reached last month. IPG, as the company being acquired, rose about 10% and was trading around $32, which is well below their 52-week high of $35.17 reached last March.

Lessons from the attempted Omnicom-Publicis merger

On the investor call this morning, Wren spoke about his previous attempt to merge Omnicom with Publicis, which ultimately fell apart in 2014. Wren said the difference between the two deals was that there is a better cultural fit with IPG.

“The difference this time around is, if you look at Interpublic and Omnicom, you look at the people that make it up, including the leadership, we actually share core values. Since the creation of both groups, I think that there’s quite a number of people who have spent time in the [each] other company over their careers,” Wren said. Because of this, a lot of “cultural unspoken things” that got in the way of the previous deal wouldn’t affect this deal, he added.

“Having had that experience, and putting myself in the situation where this is going to be tried twice, and both times by me, [I] took a lot of time and care as did Philippe to make certain that that the lessons learned a decade ago are not going to be repeated.”

Omnicom and IPG are “pretty confident” the deal will not “create any regulatory issues,” Wren said, adding that “there’s reason to believe” the incoming Trump administration will be “more friendly to business.”

Wren said that when Publicis and Omnicom attempted to merge, Omnicom didn’t have a “Plan B” for regulatory scrutiny. “We have prepared for those contingencies, and we’re prepared to do whatever we have to do to get regulatory approval.”

Wren also alluded to Omnicom being able to improve IPG’s principal-based media buying capabilities.

“Those are all capabilities, skills,  and processes that we can absolutely lend to IPG’s client base … that they’re in the process of doing more and more with but not to the extent of the others in the competitive set,” Wren said. Earlier this year, Krakowsky alluded to IPG getting more involved in principal-based media buying due to its growing prevalence in the industry.

Omnicom and IPG said the combined company’s largest industry would be pharmaceuticals and health care, representing 19% of combined revenue.

Exclusive for Ad Age All Access subscribers: Revenue by client sector for five major holding companies from Agency Report 2024

The first holding company

Krakowsky, in a memo to IPG staff, wrote: “Today is a historic day for a company that’s shaped our industry since its inception,” noting that Interpublic became the first holding company in 1961.

“As we all know, we are living in an era of ever-increasing, exponential change in the consumer, technology and marketing landscapes,” he wrote. “We’ve always prided ourselves on being at the forefront of this evolution, which is why today, we’re taking another bold step forward.” 

Krakowsky, in the memo, told staff that there won’t be any immediate changes to day-to-day operations.

“Ultimately, becoming a part of Omnicom will enable us to continue to invest in and prepare for a future where the pace of change is relentless,” he wrote. “Together, our new company will have breathtaking talent, reach, capabilities, and geographic presence, as well as a uniquely powerful set of platform services, positioning us for long-term success.”