Microsoft Advertising has, for the first time, put a vendor-measured number on AI Max: campaigns that switched on all three components (search term matching, text customization, and final URL expansion) produced at least 8% more conversions in early testing at similar CPA. The number arrives in the August product newsletter published August 31 by Kevin Salat, and it’s paired with a much less friendly disclosure. On October 1, Microsoft removes the ability to add a Max CPC ceiling to new campaigns using standalone Max Conversion, Max Conversion Value, and Max Click bidding strategies.
That’s the shape of the story: a performance claim and a control sunset, announced in the same breath.
PPC Land, reading an August 27 blog footnote from Carolyn Chou, Director of Product Management, surfaced the underlying dataset. Across 44 advertiser-run A/B experiments conducted between June and August 2026, the spend-weighted conversion uplift landed near 13.6%. Ten of those tests reached statistical significance, with a lower confidence bound of 8.2%. The other 34 went undescribed. The A/B design held bid strategy and campaign budget constant, which is the right way to run this test and also the reason the headline number carries more weight than the usual vendor-supplied lift figure.
The controls story is where small-team advertisers, roughly the 5-to-30-person businesses running paid search without a dedicated PPC hire, need to pay attention. AI Max shipped globally on August 19 (documented by Search Engine Journal, with Microsoft Ads Liaison Navah Hopkins crediting advertiser feedback for the guardrails that made it into launch): ad group-level settings, brand inclusions, brand exclusions, term exclusions, and URL rules. The ceilings are tight. Up to 25 term exclusions. Up to 20 brand inclusion lists, each holding up to 100 brands. New Search campaigns are created with AI Max enabled by default; opting out is a step during creation, not the path of least resistance.
Four bidding carve-outs survive the October 1 change, including Target Impression Share and Enhanced CPC. Max CPCs submitted through the API keep working through the 2026 holiday season and stop on January 12, 2027. Microsoft’s working eligibility threshold for conversion-based bidding remains 30 conversions in 30 days.
The parallel with Google is exact enough to be worth naming. As covered in our earlier report on Google flipping the switch, Google is auto-migrating campaign-level Broad Match and legacy Automatically Created Assets into its own AI Max product. Seafoam Media’s September brief reads both moves the same way: platforms are removing controls faster than they add visibility. The 8% floor is real. So is the fact that, after October 1, fewer levers exist to contain what the system decides to spend chasing it.
Sources
- https://about.ads.microsoft.com/en/blog/post/august-2026/ai-max-for-search-and-other-product-news-for-august-2026
- https://ppc.land/microsoft-says-ai-max-testers-gained-8-more-conversions/
- https://www.searchenginejournal.com/microsoft-advertising-rolls-out-ai-max-globally/586459/
- https://searchengineland.com/google-sets-ai-max-migration-timeline-for-search-campaigns-485006
- https://seafoammedia.com/thinking/brief/september-2026-marketing-news-trends-insights/