S2 EP8

The ultimate PMax negative keyword strategy to cut waste (w/ Guillaume Devinat)

Posted on:

Jul 9, 2025

To help marketers use negative keywords effectively, we spoke to Guillaume Devinat, CEO of PPC optimization platform Optmyzr, to uncover the ultimate PMax negative keyword strategy.

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Ben Harris

Content Writer

Timestamps:

0:00 - Intro

1:36 - Guillaume’s key focuses at Opteo

2:07 - How marketers are using negative keywords

4:02 - Why are negative keywords so underutilized?

7:16 - Which search terms waste the most ad spend?

10:18 - Finding the best negative keywords

14:55 - Competitor keywords as negative keywords

16:06 - Biggest sources of waste in PMax campaigns

21:48 - Managing ad placements

23:58 - Key metrics to track after making changes

28:14 - Final thoughts / outro

Overview:

Performance Max campaigns are everywhere - but most advertisers are still flying blind when it comes to controlling spend and cutting waste.

To help marketers take back control, we spoke to Guillaume Devinat, CEO of PPC optimization platform Optmyzr, and uncovered the ultimate PMax negative keyword strategy.

In the session, Guillaume reveals the findings of a huge study into how advertisers use (or don’t use) negative keywords in PMax - and shares a practical, step-by-step framework to cut waste, reduce junk traffic, and improve efficiency.

Expect to learn:

• Why 68% of PMax campaigns are running with zero negative keywords

• The most common search terms and placements that waste budget

• How to proactively identify and exclude bad traffic with n-gram analysis

• Early indicators of low-quality traffic (before conversions suffer)

• How to use ChatGPT to uncover wasteful keyword themes at scale

• Key settings in PMax that quietly drain spend if left unchecked

• How to estimate the ROI impact of negative keyword and placement exclusions

• Tips on geo targeting, content suitability, and URL expansion

• The case for lead gen advertisers to rethink their use of PMax

Prefer reading over watching? Read our full written recap of the session here

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