OpenAI claims renewed momentum as Anthropic rivalry heats up and ads loom for ChatGPT

ChatGPT

• ChatGPT exceeds 10% monthly growth, now with over 800 million weekly users
• Codex usage surged 50% in a week; new GPT-5.3-Codex model and macOS app launched
• OpenAI to test clearly labelled, non-intrusive ads in ChatGPT

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OpenAI says it is regaining momentum, even as competition in the AI chatbot and coding assistant market intensifies.In an internal Slack message sent on Friday, CEO Sam Altman told employees that ChatGPT is “back to exceeding 10% monthly growth,” signalling a rebound after months of pressure from rivals such as Anthropic and Google. According to the message, which was viewed by CNBC, OpenAI is also set to release an updated chat model this week.

ChatGPT now has more than 800 million weekly users, but the company has faced rising competition, particularly in developer-focused tools. In December, OpenAI reportedly declared a “code red” internally, temporarily pausing several projects to focus on improving ChatGPT’s performance and competitiveness.

Altman also highlighted rapid growth in OpenAI’s coding assistant, Codex. He said Codex usage grew by roughly 50% in just one week, calling the momentum “insane.” Codex competes directly with Anthropic’s Claude Code, which has gained significant traction among developers over the past year.

Last week, OpenAI launched a new Codex model, GPT-5.3-Codex, alongside a standalone macOS app for Apple computer users. OpenAI has been sharing internal data with investors suggesting that Codex is beginning to eat into Claude Code’s market share.

Despite the positive internal messaging, the week was not without controversy. Altman and other OpenAI executives publicly responded to Anthropic after the rival ran Super Bowl advertisements mocking OpenAI’s plans to introduce ads into ChatGPT. Altman described the ads as “deceptive” and said OpenAI would never implement advertising in the way depicted.

However, OpenAI is moving ahead with advertising trials. The company is expected to officially begin testing ads within ChatGPT on Monday, according to a person familiar with the matter. OpenAI has previously said the ads will be clearly labelled, appear at the bottom of responses, and will not influence the chatbot’s answers. Long term, ads are expected to account for less than half of OpenAI’s revenue.

At the same time, Altman and CFO Sarah Friar are pitching OpenAI’s growth story to investors as the company works to close what could be a $100 billion funding round. Executives are emphasising OpenAI’s consumer scale, expanding enterprise business, and access to computing resources.

The fundraising could be completed in multiple stages, potentially involving Microsoft, Nvidia, Amazon, and SoftBank.