'Big Six' no more as Omnicom absorbs IPG today, reshaping the global ad network order

New Delhi: Omnicom Group’s takeover of Interpublic Group (IPG) is expected to close today, November 26, 2025, capping a $13.25-billion all-stock merger that will create the world’s largest advertising holding company by revenue and redraw the global agency map.

The deal, first announced in December 2024, cleared its final hurdle on November 24 when the European Commission granted unconditional approval under the EU Merger Regulation, concluding that the transaction would not significantly reduce competition in any market across the European Economic Area.

Omnicom and IPG now have all key regulatory sign-offs in place, including from the US Federal Trade Commission, which earlier approved the merger subject to a consent order barring the combined company from using its media buying clout to reward or punish publishers based on political or ideological content.

Regulators in the UK, Australia, Brazil, Mexico and India have also cleared the deal, with India’s Competition Commission giving its nod in June 2025 without structural remedies, citing continued competitive pressure from WPP, Publicis, Dentsu, Havas and independent agencies.

Once the transaction is formally completed, Omnicom will absorb IPG and become home to a portfolio that includes BBDO, TBWA and DDB on one side and McCann, FCB and MullenLowe on the other.

The new group will control about $25.6 billion in combined 2023 revenue and more than 100,000 employees worldwide, pushing it ahead of WPP and Publicis in global rankings and sharply increasing its bargaining power with media platforms and publishers.

Omnicom has guided investors to expect around $750 million in annual cost synergies from the integration, primarily through streamlining overlapping leadership roles, consolidating offices and back-office functions and offshoring more work to lower-cost markets.

Leadership of the merged entity will remain firmly in Omnicom’s hands. The combined company will keep the Omnicom name, with John Wren continuing as chairman and CEO. IPG chief Philippe Krakowsky will move into the role of co-president and co-chief operating officer alongside Omnicom COO Daryl Simm, a structure that has reinforced industry perceptions of the deal as an acquisition rather than a merger of equals.

Internally, the companies have already been preparing for integration: combined headcount fell by around 5,000 during 2024 as both groups shed jobs and moved roles to lower-cost hubs, and senior management have been meeting clients and staff in key markets to reassure them about continuity.

Strategically, Omnicom is positioning the merger as a scale, data and AI play designed to compete more effectively with both rival holding companies and the big digital platforms. The enlarged group will bring together Omnicom’s Omni and Flywheel media and commerce platforms with IPG’s Acxiom data business and its media, CRM and digital capabilities, creating a combined stack that can plan, buy and measure campaigns across TV, digital, social and retail media.

Management has framed this as a shift away from traditional time-based billing and siloed agency offerings toward integrated, outcome-led solutions that use first-party data and AI tools for planning, optimisation and attribution.

For clients, the immediate attraction is access to more integrated services and a larger global footprint. With the merger, Omnicom’s media operation is set to become the largest among the big holding groups globally by billings, ahead of GroupM and Publicis Media, although GroupM remains the dominant force in crucial markets such as India.

At the same time, large advertisers will now have one fewer “super holdco” to choose from for global rosters, sharpening concerns about client conflicts in categories like automotive, FMCG and tech, where Omnicom and IPG agencies already sit on rival brands.

Regulators, however, have largely concluded that competitive dynamics will remain intact. The European Commission’s Phase I investigation found that the merged entity would hold only moderate market positions in both marketing communication services and media buying across national markets, and that clients could switch agencies relatively easily, given pitch-driven account cycles, short contract durations and limited switching costs.

On the sell side, the Commission noted that media owners in key European markets retain significant countervailing power, reducing the risk that Omnicom could distort negotiations or foreclose rivals by leveraging its larger media buying footprint.

Behind the scenes, the integration is expected to trigger a wave of agency brand and leadership restructuring over the next 12 to 24 months. Networks such as DDB and TBWA have already been the subject of speculation about global simplification, while on the IPG side, industry observers expect McCann to retain its identity and some consolidation pressure on FCB and MullenLowe in selected markets.

Omnicom and IPG have both signalled that “revenue-generating” and client-facing roles will be prioritised, but thousands of jobs in back-office, regional management and overlapping agency leadership structures are widely seen as at risk as the new group works toward its synergy targets.

The merger also has implications for smaller players. Pitch consultants and analysts expect more global and regional roster reviews as advertisers reassess their holding company relationships, creating opportunities for independent and mid-sized agencies to position themselves as more agile and less bureaucratic alternatives.

For the wider industry, today’s closing marks a symbolic turning point. A decade after the failed Omnicom–Publicis tie-up, the sector is once again confronting the question of whether bigger really is better in a world where Google, Meta, Amazon and emerging retail media platforms already command enormous influence over how ads are targeted and delivered.

If Omnicom can use its new scale to invest meaningfully in talent, technology and AI, the merger could produce a stronger, more competitive rival to both other holding groups and the platforms. 

If execution falters or integration drags on, the risk is that the deal simply magnifies existing disruptions and accelerates the flow of clients and senior talent toward independents and consultancies.

For now, what was once the “big six” of global holding companies has effectively become a “big five,” with a distinctly larger Omnicom sitting at the top.

The real verdict on whether this is an advertising apocalypse or a new era of industrial-scale, AI-driven marketing will depend on what happens long after the closing bell rings.