Google’s Rumored ‘Project Meridian’ Is Quietly Reshaping Shopping Ad Auctions

Something unusual is happening inside Google’s Shopping auction infrastructure, and the agencies who live inside Google Ads dashboards all day are starting to talk. Sources close to the matter say Google has been quietly piloting an internal initiative — reportedly codenamed Project Meridian — that reweights product listing ad quality scores in a way that appears to systematically favor first-party retailer data over third-party CSS (Comparison Shopping Service) partners. If confirmed, the implications for DTC brands that have spent the last two years optimizing their Google Shopping strategy around CSS arbitrage could be substantial.

What Exactly Is Project Meridian Allegedly Doing to Shopping Auctions?

Three independent agency sources — all of whom declined to be named citing client confidentiality — told Ecommerce Times they’ve observed anomalous CPCs and impression-share collapses on mid-market accounts spending between $80,000 and $400,000 per month on Google Shopping. The pattern reportedly began surfacing in late April 2026 and has intensified through May. Affected verticals appear to be home goods, apparel, and specialty sporting equipment.

“We had three accounts that had been running stable Performance Max and Standard Shopping campaigns for 14 months suddenly see their impression share drop by 22 to 30 percent with no corresponding budget change or feed issue,” said one senior paid search director at a Chicago-based performance agency managing roughly $12 million in annual Google spend. “Google’s rep told us it was ‘auction dynamics.’ That’s not an answer.”

“Google’s rep told us it was ‘auction dynamics.’ That’s not an answer. We’ve audited the feeds, the bids, the landing pages. Something changed on their end, not ours.” — Senior paid search director, Chicago performance agency (name withheld)

The unconfirmed theory circulating among agency operators is that Project Meridian is an attempt by Google to deprioritize CSS bid stacking — a tactic where brands use third-party CSS partners like Productsup, Feedonomics, or white-label CSS operators to enter Shopping auctions at a structural cost advantage versus Google’s own Shopping CSS. The EU mandated CSS access in 2017 following antitrust rulings, but sources allege Google has found an algorithmic — rather than policy-level — method to neutralize the advantage.

Which Agencies and Vendors Are Reportedly Most Exposed?

The vendors with the most at stake, according to sources, are the CSS-as-a-service operators who have built entire business models around the arbitrage. Several smaller UK-based CSS providers — where CSS adoption is highest due to proximity to the original EU enforcement action — have allegedly seen client churn accelerate since mid-May 2026.

On the agency side, sources say shops that built their Google Shopping pitch around CSS cost efficiency are scrambling. Tinuiti, one of the largest independent performance marketing agencies in the US, has reportedly been fielding internal questions from client teams about whether CSS-heavy strategies need to be restructured. A spokesperson for Tinuiti declined to comment for this article.

Feedonomics, the feed management platform acquired by BigCommerce in 2021 and now operating as a standalone growth business, is also reportedly monitoring the situation closely. Sources say Feedonomics account managers have been briefing select enterprise clients on contingency feed structures, though the company has made no public statement. Feedonomics did not respond to a request for comment by publication time.

• CSS-dependent mid-market DTC brands ($1M–$20M annual revenue) appear most vulnerable
• Affected categories reportedly include home goods, apparel, and sporting goods
• Impression share losses of 20–30% reported across multiple agency accounts
• Performance Max campaigns appear to be less affected than Standard Shopping, per agency sources
• UK and EU market accounts showing earlier and sharper signal, likely due to higher CSS adoption rates

Is This Google Pushing Merchants Harder Toward Performance Max?

Industry observers have a working hypothesis: Project Meridian, if it exists as described, is less about CSS specifically and more about accelerating merchant migration to Performance Max, where Google controls more of the auction and optimization logic — and where CSS advantages are structurally weaker.

Kirk Williams, founder of Zato Marketing and one of the most widely-cited independent voices in Google Shopping strategy, posted obliquely on LinkedIn last week about “unusual auction behavior in Standard Shopping” without naming any specific initiative. When reached for comment, Williams said he couldn’t confirm the Project Meridian name specifically but acknowledged the pattern is real.

“I’m hearing from enough people about the same anomalies that I don’t think this is confirmation bias. Something shifted in late April. Whether it’s intentional policy, an algorithm update, or an experiment that escaped sandbox, I genuinely don’t know. But merchants running CSS strategies should be watching their impression share daily right now.” — Kirk Williams, founder, Zato Marketing

The Performance Max angle is particularly pointed given that Google has been aggressively pushing PMax adoption since 2022. Sources allege that if Standard Shopping CSS accounts are being algorithmically deprioritized, the path of least resistance for merchants is to migrate budget into PMax — where Google’s own shopping graph and audience signals dominate, and CSS arbitrage is essentially moot.

How Are DTC Brands Actually Responding on the Ground?

Ecommerce Times spoke with two DTC operators directly about their experience. A founder running a $6M annual revenue cookware brand on Shopify said her Google Shopping ROAS dropped from 4.2x to 2.9x between April 28 and May 15, a period during which she made no campaign changes. “We use a CSS partner out of the Netherlands. Our agency flagged the drop immediately. We’ve since partially migrated budget to PMax and ROAS has partially recovered, but we’re paying more per click than we were six weeks ago.”

A second operator — running a $14M sporting goods brand across Shopify and Amazon — said his in-house paid media team has essentially paused new CSS investment pending clarity. “We’ve been using CSS for about 18 months. The cost advantage was real — we were consistently winning impressions at 15 to 20 percent lower CPC than our competitors. That edge appears to have narrowed materially. Whether it’s permanent or a test phase, we don’t know.”

What Does Google Actually Say About Any of This?

Google’s official position, per a spokesperson response to Ecommerce Times: “We don’t comment on internal project names or rumored initiatives. Our Shopping auction systems are designed to surface the most relevant products for users, and we regularly update our systems to improve quality and relevance. CSS partners continue to operate under the terms of our policies.”

That statement is unlikely to satisfy agency operators who are watching their client data in real time. Notably, Google did not deny that auction reweighting changes had been made — a detail several agency contacts pointed to as meaningful.

The European Commission’s DG Competition office, which originally mandated CSS access, declined to comment on whether any complaint had been filed related to algorithmic neutralization of CSS advantages. However, sources familiar with EU digital markets enforcement say the mechanism described — using quality score inputs rather than explicit policy to disadvantage CSS — would be “exactly the kind of technical workaround” that regulators have been warned about in prior Digital Markets Act discussions.

What Should Merchants and Agencies Do Right Now?

Whether or not Project Meridian is a real, deliberate initiative or simply a confluence of algorithm updates, the operational advice from practitioners Ecommerce Times consulted was consistent:

• Audit impression share by campaign type immediately — separate Standard Shopping from PMax in your reporting view and look for divergence since April 21
• Don’t abandon CSS positions yet — the situation is unconfirmed and may be a testable experiment that gets rolled back, as Google has done before
• Run parallel PMax campaigns at modest budget to establish a performance baseline if you haven’t already
• Contact your CSS provider directly — reputable CSS partners like Productsup and Feedonomics will have aggregate data across their client base that can help you determine if your account is anomalous or part of a systemic pattern
• Diversify Shopping traffic sources — Microsoft Shopping, which does not have a CSS arbitrage equivalent, has been gaining share quietly among DTC brands hedging Google exposure

“The merchants who will get hurt the worst are the ones who treated CSS as a permanent structural moat rather than a tactical advantage that required ongoing monitoring. Nothing in Google’s ecosystem is permanent.” — Anonymous, senior director at a top-10 US performance marketing agency

The broader context here is important: Google Shopping ad revenue is under real pressure from TikTok Shop’s native commerce funnel and Meta’s increasingly sophisticated Advantage+ Shopping Campaigns. Any move that consolidates merchant spend inside Google’s own optimization layer — i.e., Performance Max — directly serves Google’s revenue interests at a time when the company is competing hard for DTC dollars that are increasingly flowing to social commerce formats. Whether Project Meridian is a deliberate strategic maneuver or an emergent algorithm artifact, the net effect, sources say, is the same: the CSS arbitrage era in Google Shopping may be quietly ending.

Ecommerce Times will continue monitoring this situation. Merchants or agency operators with data to share can reach our editorial team through our secure tip line.