Amazon announced Thursday a partnership with OpenAI to run ad campaigns within ChatGPT, beginning with select U.S. brands. The move marks a strategic validation of conversational AI as a marketing channel and a shift in Amazon's historically protective stance toward competing AI platforms.

OpenAI's ad business recently hit a $1 billion annualized revenue run rate after launching sponsored placements in ChatGPT in February. Early advertisers included Best Buy and Williams-Sonoma.

The partnership is notable given Amazon's history of restricting access to ChatGPT, Claude, and Gemini on its webstore while building proprietary AI shopping tools. Yet Amazon itself became the top retail advertiser on ChatGPT between April and August, according to Sensor Tower, signaling where customer intent now concentrates.

Under the agreement, Amazon manages campaign setup and optimization while OpenAI's ad system controls placement decisions. Ads appear as text or images below ChatGPT responses. OpenAI labels all sponsored content.

Chris Conetta, director of omnichannel supply at Amazon's demand-side platform, said the partnership lets advertisers reach customers "where they spend time," extending campaigns to conversational interfaces.

Delta Vacations is participating in the initial trial. A user asking ChatGPT for marathon training tips, for example, might see an ad for running shoes available through Amazon.

OpenAI reported 900 million weekly active users in February. The shift toward conversational ad formats reflects a reallocation of marketing budgets toward high-intent channels where customer questions convert at different rates than display or search.