OpenAI said Monday that its advertising business has reached a $1 billion annualized revenue run rate, according to CNBC, giving the company a new revenue proof point as it prepares for what the outlet describes as an expected large initial public offering. The business is still young. CNBC reports that OpenAI began testing ads inside ChatGPT in the U.S. in February, making the ad operation roughly 200 days old. OpenAI is presenting the milestone as evidence of a more diversified business model alongside enterprise products, consumer subscriptions and usage-based application programming interfaces. The IPO context matters because CNBC says OpenAI is under pressure to justify an $852 billion valuation to investors. Advertising offers a potentially large revenue stream, but it also changes the economics and user experience of ChatGPT, a product that has been built around conversational answers rather than traditional search-style ad inventory. The ads are no longer only a U.S. experiment. CNBC reports that ChatGPT Ads are now available in more than 40 countries, and that OpenAI is rolling out self-service access across India, Europe, the Middle East and North Africa on Monday. The ads appear for OpenAI's Go subscribers and for free-tier users, which CNBC says make up the vast majority of ChatGPT's 1 billion weekly active users. OpenAI also addressed two obvious trust questions. According to CNBC, the company said its ads are clearly labeled and do not influence ChatGPT's answers. OpenAI also said advertisers do not have access to users' private conversations. The move has been controversial from the start. CNBC notes that digital advertising has long been a major profit engine for companies such as Google and Meta, but that OpenAI's push drew ridicule from Anthropic, which made OpenAI's ad strategy the focus of its first Super Bowl campaign. OpenAI said its next phase will bring ChatGPT Ads to more markets and add formats, objectives, buying options and measurement capabilities, according to CNBC. The company also said it will explore more native ways for businesses to interact with consumers inside ChatGPT, a phrase that signals more ad product development but leaves the exact formats undefined. Who benefits: OpenAI benefits if advertising becomes a fourth revenue engine alongside enterprise, subscriptions and API usage. Advertisers gain a new channel across ChatGPT's free and Go user base in more than 40 countries. Who's exposed: OpenAI is exposed to user-trust risk if ads are perceived as shaping answers, even though the company says they do not. Anthropic has already used the ad push as a competitive talking point, according to CNBC.