The ChatGPT maker is bringing in two independent ad-tech platforms to sell its unused ad inventory as its ad business scales
OpenAI has signed deals with ad-tech companies Magnite and PubMatic to fill unsold advertising space inside ChatGPT. The company that once treated ads as a last resort is now building a full ad-selling machine.
Magnite and PubMatic are sell-side platforms, usually called SSPs. Think of them as auction houses for ad space. A publisher hands over its available slots, and the SSP runs automated auctions where advertisers bid in real time.
That automated buying and selling is called programmatic advertising. Nobody negotiates each ad placement by hand. Software does the matching in milliseconds.
Under these partnerships, the two companies will handle what the industry calls remnant inventory. That is the ad space a publisher hasn’t sold through its direct deals.
The financial terms of the partnerships were not disclosed. So it is unclear how revenue will be split, or how much of ChatGPT’s inventory will flow through these channels.
Both companies are independent SSPs that compete with Google’s AdX, the ad exchange run by the biggest name in digital advertising. Both have also been focusing on agentic AI ad tools, meaning software that can make advertising decisions with less human hand-holding.
OpenAI began testing ads in ChatGPT in the United States in February 2026. The tests targeted users on the free plan and the Go tier.
By March, the ad business was running at approximately $100 million in annualized revenue. By August 2026, that figure had reached a $1 billion annualized run rate.
A quick note on that metric. An annualized run rate takes recent revenue and projects it across a full year. It’s a snapshot of current pace, not a tally of money already collected over twelve months.
As of October 21, 2026, ChatGPT ads had expanded to 89 countries and drawn more than 100,000 advertisers.
OpenAI is keeping one line in the sand. Its premium subscription tiers remain ad-free, so paying users don’t see the sponsored content that free users do.
OpenAI did not always sound this enthusiastic about advertising. The company previously described ads as a “last resort” for funding its products.
It reversed that stance as it looked to diversify its revenue streams beyond subscriptions. The Magnite and PubMatic deals add to a broader advertising ecosystem OpenAI has been assembling. That network also includes major agencies and tech platforms, giving advertisers several routes into ChatGPT.
For Magnite and PubMatic, the deals are a notable win. Independent SSPs spend much of their existence competing against Google’s AdX. Landing a supply partner like ChatGPT gives them inventory from one of the most closely watched AI products in the world.
For advertisers, programmatic access could lower the barrier to entry. Buyers already using these platforms may be able to reach ChatGPT users through tools they know, rather than setting up a separate relationship from scratch.
Because the terms were not disclosed, outsiders can’t yet judge how much these partnerships will add to OpenAI’s top line.
