Omnicom Group’s proposed acquisition of Interpublic Group of Cos. will bring together over 100,000 employees as well as the companies’ sprawling rosters of high-profile clients. While executives have publicly downplayed any client concerns, the combined ad giant would be handling work for several competing brands, according to COMvergence data analyzed by consultancy ID Comms and shared with Ad Age. 

Omnicom Chairman and CEO John Wren addressed potential client concerns during an investor call on Monday, claiming that marketers are no longer as concerned with such issues. “I’m not aware or threatened by any conflict as a result of us announcing that we’re joining forces,” said Wren, adding that, moving forward, both companies will need to assure clients that “we still love them quite as much as we did prior to this morning.”

Indeed, marketers don’t seem to be as sensitive about conflicts these days—a shift that can be partly attributed to consultancies such as Deloitte and Accenture, which work with a broad range of competing brands, marching further into the marketing services business. Many brands in certain industries, such as consumer packaged goods and financial services, still draw a hard line on conflicts, according to multiple executives and analysts previously interviewed by Ad Age.

“Things have changed in the industry. Competitive conflict has been deprioritized … Publicis is an example of someone that does it well, as seen with their pharmaceutical clients,” said Donna Sharp, managing director at MediaLink. “Clients know that these big holding companies can figure it out. The question will be what’s the value of the holding company to [the client].”

Still, Wren acknowledged that some IPG and Omnicom clients may move their business elsewhere due to the tie-up, which is set to create the world’s largest agency group, should it pass regulatory approval. “It’d be short-sighted for a big client to go through changing to a different vendor and discarding either two of us,” Wren said on the investor call. “Could it happen? Yes. Will it happen? Yes. But I think people will be short-sighted in doing that.”

The holding companies held meetings with clients after the merger was announced, according to multiple people close to the situation. These people said most meetings were positive, but added that Omnicom clients State Farm and AT&T and IPG clients Geico and T-Mobile inquired about potential conflicts.

Also read: What the Omnicom-IPG deal means for clients

To be sure, some Omnicom agencies already handle work for IPG clients included in this list, and vice-versa. Nonetheless, here are eight potential client conflicts within the Omnicom-IPG deal, organized by industry. Ad Age reached out to clients, which either did not immediately comment or declined to comment. 

In a statement, IPG said that “conflicts are a part of any business in our industry,” noting that it already manages conflicts within the categories Ad Age listed. “The brands listed work with agencies and teams, who are the key relationships. Clients also value expertise,” it stated, pointing to offerings such as its Acxiom data business. Omnicom confirmed the client list was accurate.

Projected 2024 U.S. media billings for the clients, according to figures provided by COMvergence, are included. U.S. media spend is provided in food, where IPG and Omnicom handle creative, not media, for the companies named.

More news: What Omnicom-IPG means for the media marketplace

Alcohol: Constellation Brands (IPG) and Diageo (Omnicom)

Last year, Constellation Brands​​—one of the largest beer companies in the U.S.—appointed IPG Mediabrands’ Initiative as its media agency of record in the U.S. Omnicom’s PHD has worked with Diageo, home to brands ranging from Guinness to Tanqueray, since winning the account in 2020. It’s also worth noting that Constellation recently hired Omnicom-owned GSD&M as the lead creative agency for its Corona Extra brand. (Omnicom’s OMD also works with alcohol brand Bacardi.)

2024 U.S. media billings (projected)

Constellation: $534 million
Diageo: $328 million

Finance: American Express (IPG) and Wells Fargo (Omnicom)

American Express consolidated global media planning and buying duties with IPG Mediabrands’ UM in 2018. Similarly, banking giant Wells Fargo has long worked with OMD on media. 

2024 U.S. media billings (projected)

Amex: $310 million
Wells Fargo: $314 million

Food: Ferrero (IPG) and Mars (Omnicom)

In July, Ferrero overhauled its creative agency roster following a competitive review. The candy giant chose multiple holding company agencies to handle its brands. One of those agencies was IPG’s McCann Worldgroup, which picked up creative responsibilities for Kinder and Tic Tac in Europe, Asia Pacific, the Middle East and Africa.

Omnicom works with one of Ferrero’s largest competitors, Mars, on the creative side through its agencies BBDO and DDB. It’s unclear if this merger will affect Mars’ global review, which includes media, commerce, social media, brand PR and influencer marketing, but not creative.

Earlier this year, Mars announced plans to acquire Kellanova, another snacking competitor. IPG recently expanded its relationship with Kellanova as well. It won accounts with Pringles, Cheez-It, Eggo and Rice Krispies Treats, as well as PR work for Pop-Tarts.

2024 U.S. media spend (projected) 

Ferrero: $230 million
Mars: $580 million

Insurance: Geico (IPG) and State Farm (Omnicom)

In 2023, IPG’s Mediabrands scored one of the year’s biggest wins when it was awarded Geico’s media business. IPG’s The Martin Agency, meanwhile, has handled Geico’s creative for nearly 20 years.

Omnicom handles media for Geico rival State Farm. Omnicom’s The Marketing Arm has held lead creative duties for the account since 2019, when the insurer moved to a roster agency model (it added Highdive to its agency team in July 2023). Prior to the roster move, Omnicom was State Farm’s lead creative agency for 75 years.

2024 U.S. media billings (projected)

Geico: $716 million
State Farm: $1.14 billion

Personal Care: Kenvue (IPG) and L’Oréal (Omnicom)

IPG Mediabrands handles global media (excluding Asia-Pacific) for Kenvue, a spin-off of Johnson & Johnson’s former consumer health and personal care businesses. OMG oversees U.S. media for L’Oréal through Beauty Co-Lab, a bespoke shop. 

Each holding company does work with the other’s client in some capacity, too. IPG works with L’Oréal through its largest creative network, McCann WorldGroup, while Omnicom is responsible for managing Kenvue’s global content factory, a consolidated commercial and content production operation that handles work on the CPG marketer’s ads and most other content. IPG’s FCB and Omnicom’s BBDO are also both on Kenvue’s creative roster. 

2024 U.S. media billings (projected)

Kenvue: $526 million
L’Oréal: $788 million 

OMD also handles media across North America and Europe for Beiersdorf, the maker of Nivea skincare products, the German company announced in September 2023.

Pharma: Bristol Myers Squibb (IPG) and Boehringer Ingelheim (Omnicom)

Pharmaceuticals/health care is poised to be the new agency group’s largest industry by revenue. Since 2023, IPG Mediabrands has led U.S media buying and planning for Bristol Myers Squibb’s DTC brands, while OMD has worked with pharmaceutical marketer Boehringer Ingelheim since 2019.

2024 U.S. media billings (projected)

Bristol Myers Squibb: $634 million
Boehringer Ingelheim: $95 million

Streaming: Netflix (IPG) and Disney+ (Omnicom)

IPG Mediabrands’ Mediahub handles Netflix in the U.S. Omnicom Media Group works with streaming competitor Disney+ through a bespoke agency called OMG23. 

2024 U.S. media billings (projected)

Netflix: $244 million
Disney+: $508 million

Telecom: T-Mobile (IPG) and AT&T (Omnicom)

Omnicom has a significant partnership with AT&T, for which BBDO handles creative and Hearts & Science manages media. IPG, meanwhile, looks after T-Mobile U.S. media via Initiative. 

2024 U.S. media billings (projected)

T-Mobile: $960 million
AT&T: $1.3 billion