IAB: 63% of Advertisers Now Chase New Customers as AI…

The IAB's September 2026 Outlook Study finds customer acquisition up nine points and 76% of buyers now focused on optimizing content for AI-generated answers — a shift with sharp consequences for founder-led businesses.

Customer acquisition is now the top media-investment goal for 63% of U.S. ad buyers, up nine percentage points in a single reporting cycle, according to the IAB’s 2026 Outlook Study: September Update released Sept. 10. Brand equity climbed six points to 43%. Repeat purchases held flat at 24%. The composition of the ad economy is tilting toward finding new customers, and it’s doing so at exactly the moment the discovery layer that produces those customers is being rebuilt around AI.

The IAB, surveying 211 brand and agency decision-makers, also raised its full-year U.S. ad-spend forecast to 12.3% year-over-year growth, 2.8 points above the 9.5% projection issued in January. Social media is now expected to grow 16.5% (up from 14.6%), CTV 15.6%, commerce media 13.6%, while linear TV declines 1.5%.

The more telling numbers sit inside the AI section. Optimizing content for AI-generated answers is the No. 1 area of increased buyer focus at 76%; AI LLM models follow at 72%. Using generative AI in campaigns fell to 69% from 78% in January. Meanwhile 86% of buyers are already changing, or expect to change within 12 months, how they measure media performance because of conversational AI and agents. 44% call adapting to AI-driven search their top investment challenge; 38% flag “AI slop.” 48% now measure brand visibility and citations directly inside AI tools, 44% use branded search as a proxy, and 40% have added third-party AI discovery analysis. Martech’s read of the data puts 45% at comparing AI-driven and traditional journeys, 35% on inconsistent citation data, and 30% on missing referral data.

For founder-led businesses, the implication is unsentimental. When an assistant answers a category question, only companies with earned mentions, consistent presence, and authoritative content are legible to it, the same signals IAB’s channel emphasis flags (creators at 54%, cohorts 53%, first-party publishers 48%, contextual 45%). This is the same discovery-layer story running through Cloudflare’s AI-crawler default flip and LinkedIn’s suppression of generic AI content.

LemonLime studies a company’s industry, competitors, and content and prepares branded content and outreach proactively, so a founder without a content team still shows up where AI now decides consideration.

IAB: 63% of Advertisers Now Chase New Customers as AI Rewrites Discovery

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