ChatGPT will start including advertisements beside answers for US users as OpenAI seeks a new revenue stream.

The ads will be tested first in ChatGPT for US users only, the company announced on Friday, after increasing speculation that the San Francisco firm would turn to a potential cashflow model on top of its current subscriptions.

The ads will start in the coming weeks and will be included above or below, rather than within, answers. Mock-ups circulated by the company show the ads in a tinted box. They will be served to adult users “when there’s a relevant sponsored product or service based on your current conversation”, according to OpenAI’s announcement. Ads will not be shown to users under 18 and will not appear alongside answers related to sensitive topics such as health, mental health or politics. Users will be able to click to learn about why they received a particular ad, according to OpenAI.

Previously, OpenAI’s CEO, Sam Altman, expressed reluctance to introduce ads to the chatbot: “I kind of hate ads just as an aesthetic choice.” His company has made commitments to spend more than $1tn on infrastructure supporting AI in the coming years. Altman has said that revenues are running at well over $13bn a year.

“Maybe there could be ads outside the [large language model] stream that are still really great, but the burden of proof there would have to be very high. And it would have to feel really useful to users and really clear that it was not messing with the model’s output,” Altman said recently. “I think it’d be very hard, we’d have to take a lot of care to get it right. People have a very high degree of trust in ChatGPT.”

In a blogpost on Friday, OpenAI attempted to reconcile Altman’s distaste for ads with the need for revenue: “Our enterprise and subscription businesses are already strong, and we believe in having a diverse revenue model where ads can play a part in making intelligence more accessible to everyone. Once we begin testing our first ad formats in the coming weeks and months, we look forward to getting people’s feedback.”

The company is also launching ChatGPT Go, which it bills as a low-cost subscription tier, for $8 a month.