SAN FRANCISCO, California: After years of offering its flagship chatbot to most users at no cost, OpenAI is preparing to introduce advertising to ChatGPT, marking a significant shift in how the company plans to fund its fast-growing AI services.

OpenAI said that it will soon begin testing advertisements for users who are not paying for a premium version of ChatGPT. The company said ads have not yet been rolled out, but trials will start in the coming weeks.

The move is aimed at generating revenue from ChatGPT's more than 800 million users worldwide, the vast majority of whom currently access the service for free. Despite being valued at about US$500 billion, the San Francisco-based startup has acknowledged that it spends far more than it earns.

"Most importantly: ads will not influence the answers ChatGPT gives you," said Fidji Simo, OpenAI's CEO of applications, in a social media post this week.

According to OpenAI, the digital advertisements will appear at the bottom of ChatGPT responses "when there's a relevant sponsored product or service based on your current conversation." The company said the ads "will be clearly labeled and separated from the organic answer."

Advertising would bring OpenAI closer to the business models long used by rivals Google and Meta, which dominate the digital ad market and have already embedded advertising into some of their AI-driven products.

OpenAI was initially founded as a nonprofit focused on the safe development of advanced artificial intelligence. Last year, it restructured and converted its business into a public benefit corporation. The company said this week that it would pursue advertising "always in support" of its original mission to ensure AI benefits humanity.

Still, critics warn that introducing ads into conversational AI carries risks. Miranda Bogen of the Center for Democracy and Technology said advertising could undermine user trust.

"People are using chatbots for all sorts of reasons, including as companions and advisors," said Bogen, director of the CDT's AI Governance Lab. "There's a lot at stake when that tool tries to exploit users' trust to hawk advertisers' goods."

While OpenAI generates some revenue from paid subscriptions, it faces high operating costs for its AI systems. The company has more than $1 trillion in financial obligations for the computer chips and data centers needed to run its models. Concerns that OpenAI may struggle to meet those commitments have added to investor anxiety over a potential AI bubble, particularly among backers such as Oracle and Nvidia.

OpenAI CEO Sam Altman defended the advertising push in a post on the social media platform X this week.

"It is clear to us that a lot of people want to use a lot of AI and don't want to pay, so we are hopeful a business model like this can work," Altman wrote. He added that he likes ads on Meta's Instagram because they show him products he might not otherwise discover.

OpenAI has said it will not use personal information or user prompts to collect data for advertising, but analysts remain cautious. Paddy Harrington of research group Forrester questioned how long such limits would last.

"Free services are never actually free, and these public AI platforms need to generate revenue," Harrington said. "Which leads to the adage: If the service is free, you're the product."