ChatGPT Remnant Ad Slots Open to Programmatic Buyers
Programmatic advertisers and publishers can now bid on ChatGPT's unsold ad inventory through Magnite and PubMatic auctions.
Updated on Nov. 2, 2026 in Advertising
Live Poll
Would you be fine with ads in your ChatGPT, if free users still get them?
OpenAI has signed deals with sell-side ad platforms Magnite and PubMatic to sell unsold ChatGPT ad inventory. The partnerships cover remnant inventory, meaning ad space not sold through direct deals, and their financial terms were not disclosed. Advertising technology firms and publishers that rely on programmatic auctions should watch how the ChatGPT inventory is priced.
Why it matters
OpenAI reversed its stance on advertising as it looked to diversify revenue beyond subscriptions. Routing unsold slots through established sell-side platforms lets ChatGPT's ad supply reach the same automated auction buyers that already buy from web publishers.
ChatGPT's ad business grew from about $100 million in annualized revenue in March 2026 to a $1 billion run rate by August 2026. As of October 21, 2026, ChatGPT ads had reached 89 countries and more than 100,000 advertisers, though the partnership terms with Magnite and PubMatic remain undisclosed.
The players
OpenAI
Developer of ChatGPT, which is expanding from subscription revenue into a fast-growing advertising business.
Magnite
Sell-side advertising platform that runs real-time auctions for publishers' unsold digital ad inventory.
PubMatic
Sell-side advertising platform that automates programmatic auctions for publishers' remnant ad inventory.
The details
A publisher hands over its available ad slots to a sell-side platform, which runs automated auctions in which advertisers bid in real time. Under these partnerships, Magnite and PubMatic will handle remnant inventory, meaning the ad space left after direct deals are filled. OpenAI's premium subscription tiers remain ad-free, so the advertising load falls on the free plan and the Go tier.
Timeline
February 2026: OpenAI began testing ads in ChatGPT in the United States.
March 2026: The ChatGPT ad business reached about $100 million in annualized revenue.
August 2026: The ad business reached a $1 billion annualized run rate.
October 21, 2026: ChatGPT ads had expanded to 89 countries with more than 100,000 advertisers.
November 2, 2026: OpenAI signed the ad-selling deals with Magnite and PubMatic.
Market Landscape
OpenAI is plugging ChatGPT's free-tier ad slots into the same remnant-inventory auction model that Magnite and PubMatic already run for publishers. The move places a conversational AI product inside programmatic advertising infrastructure that has long served websites and apps.
Advertisers and agencies buying programmatic inventory should expect ChatGPT remnant slots to appear through Magnite and PubMatic auctions, and should monitor pricing as the inventory scales. Publishers that compete for the same sell-side demand should watch whether ChatGPT supply shifts auction prices.
The takeaway
The ChatGPT ad rollout now runs through established sell-side platforms, which makes its inventory accessible to a large existing pool of programmatic buyers. Operators who buy or sell programmatic ads should track how Magnite and PubMatic report ChatGPT volume and pricing in upcoming quarterly results.
Further reading
For broader context on how these deals fit into the market, see our Advertising coverage.
Live Poll
Would you be fine with ads in your ChatGPT, if free users still get them?
