Alphabet's 13% Stock Plunge and the Ad Tech Bot Identity Scandal

Alphabet's share price fell roughly 13% on Thursday — its worst trading day since the company went public in 2004, according to The Wall Street Journal — after Google admitted its AI search product is dragging down search revenue growth. The same week, an academic study exposed ad tech vendors attaching real human identity data to internet bots. For media buyers, both stories land on the same question: where is your ad money actually going?

The stock plunge came straight from Wednesday's Q3 earnings call. Search revenue growth decelerated from 19% in Q1 to 17% in Q2 and 12% in Q3, as the Financial Times reported, and an investor pressed Google on the slide.

Google's chief business officer, Philipp Schindler, confirmed the cause: "the strong growth in AI Mode queries had an impact because of the lower monetization we were seeing in AI Mode." In plain terms, Google's AI search isn't just earning less than traditional search — it's actively pulling the whole search line down. "In a market worried about AI chatbots cannibalizing [Google's] key franchise, investors need to see [search] accelerating, not decelerating," David Wagner at Aptus Capital Advisors told the FT. Google's counterbet: short-term cannibalization now, greater growth later, once AI search is loaded with ads.

What did the EID study find?

Researchers from Indiana University and New Jersey Institute of Technology, working with ad tech research firms Adalytics and DeepSee.io, documented serious misuse of extended identifiers (EIDs) — persistent user identifiers such as hashed email addresses used to track people across domains and devices — in programmatic advertising.

The findings, reported in Jack Neff's writeup:

• Ad tech companies attached real human tracking data to automated bots, making it look like actual people visited certain sites.
• In some cases, vendors bundled multiple human IDs into a single bot session or advertising bid.
• Zeta Global's LiveIntent was singled out for particularly brazen behavior.
• Criteo, ID5 and Experian's Audigent were observed assigning different EIDs to separate supply paths in multi-SSP (supply-side platform) auctions.
• Flashtalking was the only vendor of 18 examined that was never documented serving human EIDs to bots; The Trade Desk came close to clean.

Here's the compliance wrinkle: this practice doesn't qualify as sophisticated invalid traffic under Media Rating Council standards. An MRC spokesperson told Neff the organization "does not currently audit or accredit any identity solutions/providers nor audience targeting." So buyers can't count on accreditation to catch it — demand documentation from your identity vendors directly.

TelevisaUnivision's split quarter

Sports rights increasingly decide media earnings, and TelevisaUnivision's Q3 proves it. US revenue fell 14%, with US advertising revenue down a bruising 24%, partly because rival Telemundo holds Spanish-language US rights to the 2026 FIFA World Cup.

Latin America offset the damage. TelevisaUnivision airs the tournament there through its TV network and streaming service ViX, and the company credits that coverage for a 30% rise in overall subscription and licensing revenue. Quarterly revenue in the region jumped 51%, with Mexican ad revenue up 19%. Net effect: total ad revenue declined 5% — painful, but far better than the US number alone. Executives told investors they'll keep expanding the sports portfolio across linear and streaming.

In brief

• WPP's Q3 revenue slipped 2.1%, but WPP Media posted positive growth — 0.3% — for the first time in six quarters. CEO Cindy Rose has detailed how the holding company's priorities shifted since she took over last year.
• Health, food and news publishers have seen the steepest organic search traffic declines over the past two years, and search ads share the blame alongside AI, per Search Engine Land.
• The Trump administration is increasingly subpoenaing Big Tech companies for information on users who criticize its immigration policies, the WSJ reports.
• Nearly three months after Walmart closed its acquisition of CTV ad platform Vibe.co, Vibe's brand customers can now build campaigns using Walmart audience data.
• Stagwell hired Alison Vacovec as SVP of growth for The Marketing Cloud.

What changes for practitioners?

Two practical takeaways: if you buy programmatically, audit which identity vendors touch your bids and whether human EIDs reach bot traffic — no auditor will do it for you. And if your revenue depends on Google search traffic or search-adjacent ad spend, expect monetization gaps in AI Mode to keep compressing growth until Google switches ads on there. That transition window is the story to watch next quarter.