IAB sorts AI shopping into three paths for credit claims

MarTech’s account sets out the method. The blueprint asks three questions: who created the intent, who made the decision and who completed the purchase. Those answers settle which party may claim the sale and what proof it needs. Two kinds of claim follow. A contributory claim is for a party that helped shape the outcome without making the decision; a party that made or influenced the decision itself files a decision claim.

Caroline Giegerich, the IAB’s vice president of AI, told a roundtable the document became “more of a call to action”, Digiday reports, because the data sits inside the AI platforms. Similarweb figures in the report show why. A shopper whom an AI assistant points to a brand is 2.5 times as likely to visit that brand’s website within a week. Of those visits, 55.9% are attributed to search and 19.9% to direct traffic, and only 8.8% arrive as AI referrals.

The ad side has a count of sorts: our AI ads census lists the IAB’s estimate, from US buyers surveyed in July 2025, that about 39% of the digital ads US advertisers buy in 2026 would be built with AI, a survey answer, since no platform publishes the share.

On those Similarweb shares, a brand that credits AI only with its AI referrals counts 8.8% of the site visits made by shoppers an assistant recommended it to, while more than half of those visits land in its search numbers.