WPP says Safari identity block leaves InfoSum untouched

Apple started blocking identity resolution firms in Safari with an Oct. 19 blog post titled "Blocking Identity Resolution Infrastructure," and WPP CEO Cindy Rose says the crackdown barely touches the holding company. Her reason: WPP's data stack no longer depends on the email-matching technique Apple is shutting down.

"What I will say is it doesn't really impact our data solution at all because we don't rely solely on identity matching," Rose said on WPP's third-quarter earnings call, responding to a question from Richard Kramer, founder of Arete Research.

What is Apple actually blocking?

Identity resolution grew up as a workaround for the cookie's slow death. Publishers ask visitors for an email at log-in, subscription or checkout, then run code from firms like LiveRamp, ID5 or The Trade Desk's UID 2.0. The code scrambles the address into a string of characters, sends it to the firm, and gets back an ID — the same ID on every site using the service, which lets advertisers recognize one person across a news site, a retailer and a recipe blog.

Apple's engineers argue the plumbing pitch misses the point. Each site shares only its own customers' details, but the firm in the middle sees the same email arrive from all of them and can connect a person's activity in a way no single site could. Apple also said nobody signing up for a newsletter expects their address to reach a third party.

Why does this matter for WPP vs. Publicis?

Rose used the question to relitigate WPP's InfoSum purchase, a deal many in the industry questioned in April 2025.

"We bought InfoSum roughly two years ago. We've now fully integrated it into our WPP Open platform. It is a data collaboration platform that relies on a mix of data sources from consumer identity to our own WPP proprietary data to live signals from our ecosystem of data partners, nearly 400 of them," Rose said, adding that the impact of the iOS changes on WPP is "minimal."

The contrast with Publicis is stark. Publicis agreed to pay $2.2 billion for LiveRamp this May — and five months later, LiveRamp sits on Apple's blocklist. WPP had already stopped using LiveRamp by June.

The difference is where the matching happens. Apple's block works in the browser, cutting Safari off from code that collects emails on a publisher's page. InfoSum runs server-side: each party's data stays in its own sealed environment — in WPP's newer setup, inside the client or publisher's own systems — with only insights shared between them. Safari can't reach that.

"The subtext of course is that their deadly rival, Publicis, is dancing to a different tune," said Charles Ping, managing director at Winterberry Group. "If Cindy can make the $2billion+ that Publicis spent on Liveramp (plus Lotame and Epsilon before that) by contrast look poor both strategically and financially on an earnings call then that's a strategic investor message nailed. And none of Publicis' acquisitions have delivered European capability."

Is WPP really unscathed?

Not entirely. Consumer identity is still one of InfoSum's inputs, and connecting what different companies know about the same people sits close to what Apple objected to — just with data the parties already hold, outside the browser's reach.

"In reality, this does not mean WPP is unscathed," said Robert Webster, founder of AI marketing consultancy TAU and a former WPP exec. "It also need signals to deliver on safari and those signals have been degraded from them as from everyone else. Many of the ad tech systems WPP uses are equally encumbered, if not more so by Apple's policies — moreso because without the email match grids they are not able to bring tougher sufficiency login data to make up for Publicis' well known advantage in match rate across email graphs."

What else happened on the call?

WPP's turnaround showed signs of momentum. WPP Media's revenue excluding pass-through costs grew 0.3% like-for-like in the third quarter, reversing a 2.8% decline the previous quarter.

Rose also defended WPP's decision to skip the pitch for Coca-Cola's North American media account while defending the roughly $2 billion Coke spends on media, data and tech everywhere else. WPP lost the North American account to Publicis last year, and pitching again 18 months later would have meant heavy spend to win back business Coke had just moved.

"We made a tough call between spending yet another six weeks pitching for North America versus delivering against what we had already won," Rose said. "It was a fine judgment call, which I made, and it is as simple as that, really."

The Safari block will keep pushing ad tech toward server-side setups, but as Webster's critique shows, no holding company — WPP included — is fully clear of Apple's signal loss yet.