• by Laurie Sullivan , Staff Writer @lauriesullivan, Yesterday

Advertisers stepped more cautiously across Amazon Prime Day, with media spend on the first two days dropping sharply, compared with last year.

Independent ad agency Tinuiti notes that if the third and fourth days show stronger performance, spend may still surpass 2024 for Amazon’s four-day Prime event.

Amazon took a big gamble this year by expanding its annual Prime Day summer sale to four days from two, giving shoppers more time to find what they need. Consumers wouldn’t need more time, however, if they used Amazon’s AI assistant Rufus -- at least in theory.

Adobe Analytics observed that generative AI (GAI) use spiked. Consumers embraced GAI-powered chat services and browsers as a shopping assistant, but not necessarily Rufus.

GAI traffic to U.S. retail sites on the first day, measured by shoppers clicking on a link, rose by 4,100% year-over-year (YoY). And while AI-driven traffic remained modest compared with other channels such as paid search and email, the growth shows the impact of GAI on shoppers looking for deals or specific product details.  

Tinuiti reported that ad costs dropped for the first two days while engagement surged, with Sponsored Products cost per click (CPCs) down 10% and aggregated demand sale price (ADSP) CPMs down 23% year-over-year.

Click-through rates (CTRs) for Sponsored Products -- which accounts for the majority of Amazon search placements -- jumped 89%, signaling stronger consumer interaction despite lower spend, according to Tinuiti Senior Innovation & Growth Director Joe O’Connor.

O’Connor suggested the decline could have prompted by the need for many brands to stretch out budgets to four days from two.

“If our second day spend is representative of what to expect in the third and fourth days, we will likely pace to exceed the numbers delivered from last year's event,” O’Connor said.

Since conversions and revenue are down, it could mean Amazon shoppers are researching during the event. They are clicking on ads to visit pages, but not completing their purchases. This could bode well for conversion later in the event and create opportunities for retargeting.

The insights align with Tinuiti’s recent 2025 Prime Day Study that highlights a 31% increase in expected spend due to the longer format and a 34% uptick in shoppers planning to use ChatGPT to research deals.

Tinuiti surveyed 1,002 U.S. Amazon Prime members between May 6 and May 9, 2025 to better understand how this year’s event will differ from years past, given developments such as increased tariffs, the adoption of AI-powered shopping assistants, and Amazon’s move to extend Prime Day to four days.

More than 80% of Prime members surveyed expected to shop on Amazon during Prime Day this year -- an uptick from 68% who say they did so last year.

Expectations of shopping during Prime Day were consistent across generations, with 85% of Gen Z, millennial, and Gen X Prime members planning to shop along with 84% of baby boomers.