Anthropic’s blockbuster $1.5 trillion (£1.1 trillion) stock market listing could be delayed or forced into a dramatic valuation cut after a brutal Wall Street sell-off left investors questioning the price tag on one of the world’s most valuable AI firms.

The ChatGPT rival is facing growing pressure to lower its valuation as a rout in tech stocks threaten to derail what could become the largest initial public offering in history.

The Nasdaq plunged around six per cent on Thursday, wiping roughly $2.5 trillion from US tech stocks as investors fled AI-related firms following the US midterm elections.

Three major investors considering participating in Anthropic’s IPO believe its proposed $1.5 trillion valuation will need to come down, according to the Wall Street Journal, with one suggesting a figure closer to $1 trillion.

“The road show is due to kick off next week but the $1.5 trillion valuation seems toppy and maybe needs to be adjusted lower to attract potential investors,” he said.

“Market reaction today could be key. A rebound in the tech sector may alleviate worries a little, but the seed of worry has been planted, that’s for sure.”

The uncertainty comes just days before Anthropic was expected to begin pitching its shares to institutional investors, with pricing initially anticipated later this month.

Anthropic faces $500bn valuation haircut

Anthropic, founded in 2021 by former OpenAI researchers including Dario Amodei, has become one of the biggest beneficiaries of the AI investment boom, attracting billions from backers including Amazon and Google.

The company was valued at $965bn in May, with expectations that its stock market debut could push that figure as high as $1.5 trillion.

But investors are increasingly questioning whether the extraordinary growth of AI companies can justify their valuations, particularly as the cost of building the infrastructure needed to power their models continues to soar.

Nalin Patel, director of EMEA private capital research at Pitchbook, told : “A postponement would protect against near-term valuation risks and would be more likely if the correction sustains over a longer period”.

“A valuation haircut, which would not be ideal for existing investors, could generate greater demand from new investors if the IPO must proceed by a certain time”.

The company reported revenue of more than $33bn in the first nine months of 2026, but its growth slowed between the second and third quarters while enormous spending commitments continued to weigh on its finances.

Its IPO prospectus disclosed more than $800bn in computing and infrastructure commitments extending into the next two decades.

Investors are also awaiting Anthropic’s October revenue figures, which were left blank in an updated regulatory filing, to assess whether growth has accelerated following the recent slowdown.

“Anthropic’s IPO increasingly looks like a question of timing and valuation”, he said.

“Rapid revenue growth and enormous future compute requirements strengthen the case for public capital, while slowing sequential growth, losses, and infrastructure commitments increase investor scrutiny”.

He added that the market sell-off could push Anthropic to accept a lower valuation or postpone its listing without fundamentally weakening the case for going public.

AI backlash adds to Anthropic IPO pressure

The market turmoil follows sweeping Democratic gains in Tuesday’s US midterm elections, which have intensified concerns over political opposition to the rapid expansion of AI data centres.

Several states have seen growing resistance to the construction of energy-hungry facilities amid fears over electricity prices, water consumption and pressure on local infrastructure.

The backlash has added to investors’ concerns about the hundreds of billions of dollars being committed to AI infrastructure, particularly by companies relying on debt to fund construction.

Malik Ahmed Khan, senior equity analyst at Morningstar, said the election results had increased uncertainty around data centre development, particularly in Texas, where opposition has emerged across party lines.

“Near term, we do see heightened uncertainty around the AI data center buildout”, he said.

However, Khan argued that Anthropic’s emphasis on AI safety could eventually work in its favour if Democrats pushed for tighter regulation.

“Paradoxically, Anthropic, with its focus on building AI for humanity and its famous spat with the DoW, may actually benefit from increased AI regulation from Democrats”, he said.

The sell-off has also hit AI infrastructure companies including Coreweave, Nebius and Iren, whose shares have suffered steep losses as investors reassess the risks of the sector’s spending spree.