The Relentless Rivalry Between OpenAI and Anthropic

Sam Altman's OpenAI and Dario Amodei's Anthropic are widely seen as the two forces setting the pace of modern artificial intelligence. What many overlook is that the pair once worked side by side before heading in opposite directions.

The break came in late 2020, when Amodei walked away from OpenAI amid disagreements over how aggressively to commercialize the technology and how much weight to give safety. He went on to found Anthropic, building its Claude models around a safety-first philosophy.

From ChatGPT to open confrontation

Tensions sharpened after ChatGPT launched in November 2022. According to Reuters, Altman is said to have pushed the product out roughly two weeks after learning that Anthropic was building something similar. More recently the two have clashed on several fronts, from Pentagon contracts to dueling Super Bowl advertisements.

By June 2026, the valuation balance had tilted toward Anthropic. Following a May 28 round that raised 65 billion dollars, the company hit a valuation of 965 billion dollars, edging past the 852 billion dollars OpenAI posted in March 2026.

Anthropic's 965 billion dollars tops OpenAI's 852 billion; Claude's monthly users surged 640% to 56 million, while ChatGPT grew 62% and crossed 1 billion users.

The race grew tighter still as both companies filed IPO applications just days apart, on June 1 and June 8. On growth, Claude sprinted ahead with a 640% jump in monthly active users to 56 million, while ChatGPT retained commanding scale with 1 billion users and 62% growth.

The picture reveals two contrasting strategies: OpenAI leans on sheer scale, while Anthropic rides rapid momentum and a safety narrative to close the gap, and even pull ahead on certain metrics.