WPP flags programmatic concerns around Publicis’ Epsilon platform in new report

In an unusually direct move, WPP has taken aim at rival Publicis Groupe, alleging that its Epsilon-run supply-side platform (SSP) is flooding the digital ecosystem with subpar ad inventory. The accusations were outlined in a client-facing ‘intelligence report’ from WPP Media, which claims that Epsilon’s inventory fails to meet industry benchmarks for viewability and user attention, turning what was once a quiet rivalry into a very public dispute.

According to reports by international media, WPP CEO Mark Read has been cautioning clients privately of Publicis about Epsilon’s Conversant SSP for over a year, raising red flags about low-quality, ‘made-for-advertising’ inventory and murky supply paths, some of which echo findings from an unreleased Adalytics report.
The new WPP Media report was first circulated internally among client team leads, who were then given discretion to share it with brands or use it to guide conversations.

WPP’s public attack on Publicis highlights deepening cracks in the media supply chain, as brands demand more transparency and quality in programmatic buying. The clash comes amid fierce competition for data-driven growth and client retention in a tightening market.

WPP is under pressure—its organic growth trails peers, and the looming Omnicom-IPG merger could knock it from the top spot. CEO Mark Read’s planned exit this year adds to the uncertainty. Publicis, meanwhile, has momentum, recently winning Coca-Cola’s North America media business from WPP and now competing for Mars globally.

As per Ad Age’s report, they obtained a WPP research report, sent to clients in late May, which among other things, reveals insights from a programmatic buying test WPP ran with its own money on May 19-20. The report indicated that 26% of 500,000 impressions were from ‘made for advertising’ (MFA) sites, web pages specifically built to maximize ad displays, often characterized by dense layouts and quick ad refreshes for cheap CPMs. Furthermore, the report highlighted that 25% of the inventory was sourced from a retail site within the Publicis-owned CitrusAd media network, achieving a mere 2% viewability.