For the better part of 18 months, Performance Max has been Google’s fastest-growing ad product inside ecommerce. But as DTC brands head into the second half of 2026, a growing contingent of Shopify merchants and agency operators are sounding the alarm: PMax isn’t just competing for new customers—it’s quietly consuming the branded search budget they were already winning for free.
The mechanics are well understood at this point but still underappreciated operationally. When a shopper types a brand name directly into Google Search, Performance Max campaigns—if left unconfigured—will bid on that query, claim the conversion, and report a blended ROAS that looks stellar. The actual incremental lift, however, is negligible. The customer was coming anyway.
“We were showing a 6.2x ROAS on our PMax campaign for Q1 and feeling great about it,” said Carly Nguyen, head of growth at Los Angeles-based skincare brand Glow Standard, which does roughly $18M in annual DTC revenue on Shopify. “Then our agency ran an incrementality test through Northbeam and we found out that 61% of those conversions were branded—people who’d already visited our site twice. We were basically paying Google to intercept our own returning customers.”
How widespread is the PMax cannibalization problem among Shopify brands?
The issue appears to be systemic rather than edge-case. According to data shared by paid search agency Structured Agency, which manages Google Ads for more than 200 Shopify merchants, 74% of PMax accounts audited in May 2026 showed branded query share above 45% of total PMax impressions—up from 58% of accounts showing that figure in mid-2025.
The uptick correlates directly with Google’s January 2026 expansion of PMax’s Search signal matching, which broadened the campaign type’s access to navigational and brand-adjacent queries. Google framed the change as improving relevance. For merchants without tightly managed brand exclusion lists, the practical effect was that PMax began bidding more aggressively on queries like “[BrandName] reviews,” “[BrandName] discount code,” and even direct brand name searches.
“Google made it harder to exclude branded terms from PMax in the same update cycle where they gave it more search inventory. That’s not a coincidence—that’s product design that benefits Google’s revenue line.” — Aaron Nosbisch, founder of BREZ and former agency operator, speaking at Commerce House Austin, May 2026
Nosbisch, who has publicly documented his own PMax experiments across his beverage brand’s $2.1M Google Ads spend, says he now runs separate branded search campaigns with negative keyword lists pushed into PMax exclusions at the campaign level—a workaround Google technically supports but doesn’t surface prominently in its own optimization recommendations.
What’s the actual revenue impact on mid-market DTC merchants?
Quantifying the true cost is difficult because it requires incrementality infrastructure most mid-market brands don’t have. But those who have run the tests are reporting meaningful discrepancies between reported and actual performance.
Obvi, the collagen supplement-adjacent nutrition brand that has scaled aggressively on Shopify Plus, ran a four-week geo-based holdout test in March 2026, suppressing PMax in three DMAs while maintaining it in six comparable markets. The result: overall conversion volume dropped 9% in holdout markets, but revenue per session from new visitors—the metric that actually signals customer acquisition—was statistically identical across groups.
“What that told us is PMax was doing almost nothing for net-new customer acquisition,” said Ron Shah, Obvi’s co-founder, who has been vocal about the brand’s attribution experiments on social media. “It was just taking credit for people who found us through TikTok Shop or our email flows and then Googled our name before checking out. Those aren’t PMax customers. Those are Klaviyo customers.”
“PMax ROAS is the most misleading single number in DTC right now. If you’re not running incrementality tests, you don’t know what you’re actually buying.” — Ron Shah, co-founder, Obvi
Are Google’s own tools giving merchants a way out?
Technically, yes—but the remedies require operational effort that most merchants aren’t applying. The current playbook recommended by agencies running clean PMax accounts includes several non-negotiable steps:
- Brand exclusion lists at the MCC level: Push a consolidated negative keyword list that includes all brand name variants, common misspellings, and brand-plus-modifier queries (e.g., “[Brand] promo,” “[Brand] return policy”) up to the Google Ads manager account level so exclusions propagate across all campaigns.
- Separate branded search campaigns running in parallel: Maintain a dedicated branded search campaign with exact and phrase match on brand terms, with PMax excluded from those queries via the brand exclusion tool Google added in Q3 2025.
- Asset group segmentation by audience temperature: Split PMax asset groups so prospecting creative (cold audiences, lookalikes) is separated from retargeting signals. This gives the campaign less opportunity to collapse warm and cold attribution into a single ROAS figure.
- Third-party attribution layered on top: Tools like Northbeam, Triple Whale’s Statlas layer, or Rockerbox are now considered table stakes for any brand spending above $50K/month on Google. Self-reported Google ROAS without a cross-channel attribution layer is operationally unreliable.
- Incrementality testing on a quarterly cadence: Geo-based holdout tests or synthetic control experiments (Triple Whale’s iROAS tool now automates this for Shopify merchants at the $30K+/month threshold) should run at least once per quarter per major channel.
How are agencies repositioning their Google Ads services around this?
The cannibalization problem is quietly reshaping how performance agencies price and scope Google Ads engagements. Several mid-size agencies reached for comment say they’ve added PMax audits as a standalone paid service—typically priced at $2,500 to $4,500—that precedes any ongoing retainer.
“We started doing PMax audits separately because we kept inheriting accounts where the client thought they had a 5x ROAS on Google and the reality was they had a 2x ROAS on actual new customer acquisition and Google was taking 30% of their organic branded traffic in the process,” said Margo Preis, director of paid media at Curio Commerce, a Portland-based agency managing Google Ads for 40-plus Shopify brands. “Walking a client back from a 5x to a 2x number is a hard conversation, but it’s the honest one.”
Preis says Curio now requires all new clients to install Northbeam or Triple Whale before the agency will launch any PMax campaign. Without cross-channel attribution, she argues, there’s no responsible way to set budget recommendations.
Is Google Shopping inside PMax still worth running for DTC product discovery?
The cannibalization critique is largely about Search inventory within PMax—not Shopping. The consensus among practitioners is that Shopping placements inside PMax continue to deliver genuine new-customer acquisition, particularly for categories with strong visual appeal (apparel, home goods, beauty) where product images in Shopping results create first-touch impressions from non-branded queries.
“The Shopping component of PMax is genuinely valuable,” said John Dobrowolski, Amazon and Google Ads lead at Pilothouse Digital, which manages media for brands including Ridge Wallet and other high-volume DTC operators. “The problem is you can’t surgically separate Shopping from Search inside PMax without running standard Shopping campaigns alongside it, which Google now actively discourages. They want everything in PMax. That’s a conflict of interest.”
Dobrowolski’s current recommended structure for brands spending $75K to $250K/month on Google: a PMax campaign with Shopping assets and aggressive audience signals, a separate Standard Shopping campaign running simultaneously (Google still allows this despite PMax priority settings), a branded search campaign fully isolated, and non-brand exact match campaigns for high-intent category terms that PMax tends to underserve.
“The merchants who are winning on Google in 2026 are the ones who stopped trusting PMax as a black box and started building campaign architecture that forces transparency. It takes more operational overhead, but the actual ROAS—the real one—is meaningfully higher.” — John Dobrowolski, Google Ads lead, Pilothouse Digital
What should Shopify merchants do before Q3 budgets lock in?
With Q3 planning cycles underway for most DTC brands—particularly those with peak seasons running August through November—the operational window to restructure Google Ads accounts before holiday spend scales up is narrowing. Practitioners recommend a specific sequence before budgets finalize:
- Pull a Search Terms report from your PMax campaign filtered to the last 90 days and calculate what percentage of impressions and conversions came from branded queries. If it’s above 30%, the account needs immediate restructuring.
- Audit your Google Ads conversion actions to ensure you’re tracking new customer purchases separately from returning customer purchases. Shopify’s Google & YouTube app now supports customer tag-based conversion segmentation natively as of its May 2026 update.
- Run Google’s Brand Exclusion tool (found under Tools > Shared Library > Brand Lists) and build a comprehensive exclusion list before Q3 budgets activate.
- If you’re spending above $40K/month on Google and haven’t run an incrementality test in 2026, treat that as a P0 task before increasing budget further.
The broader tension here isn’t going away. Google’s financial incentives and merchant interests are structurally misaligned inside Performance Max—a campaign type designed to maximize Google’s yield across its inventory, not to minimize your customer acquisition cost. The merchants navigating it most effectively in 2026 are treating PMax as a managed input in a larger system, not as a self-optimizing solution. The distinction is expensive to learn the hard way.
