AI chatbot maker Anthropic is seeking a stock market valuation of up to $1.4trn (£1trn).
It means the maker of the Claude AI assistant will not launch the largest public listing, as had been anticipated.
Instead, Elon Musk's company SpaceX will remain the most expensive initial public offering (IPO) at $1.77trn.
The target valuation, however, would still make Anthropic one of the most valuable companies in the world.
It would be behind just a handful of tech giants in value, with titans like Nvidia, Apple and Microsoft outpacing it.
While the values are eye-watering - as one trillion seconds equals 31,689 years - it's lower than had been anticipated by Wall Street analysts.
By comparison, one million seconds is 11.5 days; a billion seconds amounts to more than 31 years.
A $2bn valuation had been discussed before $1.5bn was expected by analysts.
The drop to $1.4trn comes as concern over AI spending mounts.
On Friday, tech stocks experienced a sell-off as the US midterms heralded a blue tsunami of Democratic victories, some of whom benefited from anti-data centre and anti-AI policies.
There had been speculation that Anthropic would delay its IPO as a result.
But the announcement coincides with another rally in tech stocks as the Friday falls reversed.
The world's most valuable company, the AI chip maker Nvidia, is still suffering losses as its founder and chief executive, Jensen Huang, admitted to having an affair.
The woman he had the affair with is an alleged Chinese spy and Donald Trump has said the FBI is looking into the Nvidia CEO.
(c) Sky News 2026: Claude maker Anthropic seeks $1.4trn valuation amid worry over AI investment
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