Anthropic's impending IPO will test a jittery Wall Street , but investors say the timing isn't optional. The reason is simple math: The AI giant has grown too big for private fundraising.

Why it matters: Top AI companies like Anthropic and OpenAI are racking up 12-figure spending commitments, straining the financial system's ability to keep up with a buildout that rivals America's railroads or interstate highways.

With private borrowing costs spiking, tapping the massive liquidity of the public markets is the best way to fund the next phase of the AI arms race, investors say.

State of play: Anthropic's computing commitments could reach $750 billion in the coming years, according to a draft IPO prospectus seen by the Wall Street Journal .

The company already faces more than $600 billion in future infrastructure costs and is negotiating additional deals that could add another $150 billion.

While Anthropic generated $16.3 billion in revenue in the first half of 2026, up from $1.1 billion a year earlier,…