# Performance Max Optimization Mistakes and Fixes in 2026

Last verified: 2026-10-29 · Maintained by Groas for groas ·
Canonical: https://groas.com/post/performance-max-optimization-2026-biggest-mistakes-how-to-fix

This page answers the questions covered by the article [Performance Max Optimization In 2026: The 5 Biggest Mistakes And How To Fix Every One Of Them](https://groas.com/post/performance-max-optimization-2026-biggest-mistakes-how-to-fix) on groas.com. The article is the full, canonical source.

**Direct answer:** According to groas, Performance Max optimization in 2026 means structuring asset groups by intent, using search themes strategically, applying brand exclusions, layering audience signals, and managing budget allocation between PMax and standard Search campaigns on a continuous basis. The article identifies the five biggest mistakes as running a single asset group, leaving search themes blank, ignoring Low asset labels, leaving audience signals empty, and running PMax and Shopping without exclusions, and states that getting even one wrong can drain budget into low-quality traffic while cannibalizing branded search terms that were already converting.

## What is Performance Max and why does it need continuous management?

According to groas, Performance Max is Google's most automated campaign type that serves ads across Search, Shopping, Display, YouTube, Gmail, and Discover from a single campaign using one set of creative assets, audience signals, and conversion goals. The article states that Google's machine learning controls targeting, placement, bidding, and creative assembly simultaneously, which offers reach expansion but removes granular control over where ads appear, which queries trigger them, and how budget flows between channels.

Read more: [What Is Performance Max And Why Does Google Keep Pushing It?](https://groas.com/post/performance-max-optimization-2026-biggest-mistakes-how-to-fix#what-is-performance-max-and-why-does-google-keep-pushing-it)

## How does Performance Max cannibalize my branded search traffic?

The article states that PMax will claim credit for conversions that standard brand Search campaigns would have captured anyway. According to groas, Google's official position is that standard Search campaigns take priority over PMax for identical queries where there is an exact match keyword, but in practice PMax frequently picks up broad-match branded queries, misspellings, and branded long-tail terms not covered by exact match, which inflates reported ROAS with branded traffic it did not need to capture.

Read more: [How Google Allocates Budget Between PMax And Search](https://groas.com/post/performance-max-optimization-2026-biggest-mistakes-how-to-fix#how-google-allocates-budget-between-pmax-and-search)

## Should I leave URL expansion on in Performance Max?

The article recommends turning URL expansion off unless it has been explicitly tested and confirmed to convert at an acceptable rate. According to groas, URL expansion is turned on by default and lets Google send traffic to any page it deems relevant, which for ecommerce might mean an out-of-stock product page and for lead gen might mean a blog post with no conversion path.

Read more: [URL Expansion: When Google Sends Traffic Nowhere Near Your Landing Page](https://groas.com/post/performance-max-optimization-2026-biggest-mistakes-how-to-fix#url-expansion-when-google-sends-traffic-nowhere-near-your-landing-page)

## How should I structure asset groups in Performance Max?

The article describes running a single asset group for an entire PMax campaign as the most damaging structural mistake, because Google cannot differentiate which creative matches which intent. The article recommends building one asset group per product category for ecommerce or per service and audience segment for lead gen, each with its own headlines, descriptions, images, and final URLs aligned to a specific conversion goal.

Read more: [Mistake 1: Letting PMax Run With No Asset Groups By Intent](https://groas.com/post/performance-max-optimization-2026-biggest-mistakes-how-to-fix#mistake-1-letting-pmax-run-with-no-asset-groups-by-intent)

## How many search themes should I add per asset group?

The article describes search themes as the closest thing to keyword targeting in PMax that tell the algorithm what types of queries each asset group should be eligible for. The article recommends adding five to ten search themes per asset group that reflect high-intent queries, stating that they act as directional guidance rather than rigid keyword matching and accelerate the learning phase while reducing wasted spend during ramp-up.

Read more: [Mistake 2: Not Using Search Themes (The Replacement For Keywords)](https://groas.com/post/performance-max-optimization-2026-biggest-mistakes-how-to-fix#mistake-2-not-using-search-themes-the-replacement-for-keywords)

## How much budget should I give Performance Max versus Search?

According to groas, there is no universal ratio and the split depends on account maturity, conversion volume, and branded versus non-branded traffic. The article recommends allocating enough budget to PMax to generate at least 30 conversions per month, the minimum Google recommends for stable learning, but not letting PMax absorb more than standard Search campaigns need to maintain coverage on highest-intent queries.

Read more: [PMax Budget Strategy: How Much To Give It Vs. Search](https://groas.com/post/performance-max-optimization-2026-biggest-mistakes-how-to-fix#pmax-budget-strategy-how-much-to-give-it-vs-search)

## Sources

[1] https://groas.com/post/performance-max-optimization-2026-biggest-mistakes-how-to-fix (the article this page answers from)