AI companies for years have promised that smarter models would be worth the staggering cost to build them. Anthropic on Wednesday made that case in cash.

The company presented eye-popping financials to investors, saying it was cash flow positive in the third quarter, with revenue surging nearly 50% to $16.8 billion compared with the April-to-June period.

Why it matters: As Wall Street broadly spent the day fearing an AI bubble, Anthropic offered what investors have been desperate to see: evidence that frontier AI can be a sustainable business .

State of play: The S&P 500 fell by more than 1% for the first time in 53 sessions, while Anthropic showed off a balance sheet that promises profitable AI, sources told Axios.

Zoom in: Consider just one of the stats reported by Anthropic: The company is cash flow positive even as some of the world's most profitable companies are struggling to keep their AI spending in check.

For context, Google parent Alphabet, long a money-printing machine, turned free cash flow…