AI Spending Worries Drive Tech Stocks Lower

Anthropic says it blocked roughly 24,000 fake accounts that Chinese AI labs used to access its Claude model. The move cut off paying customers who accounted for between 5% and 7% of its revenue in the first nine months of the year. DeepSeek, Moonshot and MiniMax generated more than 16 million interactions with Claude in February, the company said, violating its terms of service. The market report also covered technology investment, oil prices and equity markets; it contained no reporting on migration or border enforcement.

AI investment and investor concerns

Anthropic describes the practice, known as distillation, as a loss of intellectual property with national security implications. Earlier this month, it introduced access restrictions and proxy blocking, then banned tens of thousands of accounts. The company said those measures cut off 90% to 99% of the data being siphoned and effectively stopped Chinese developers from distilling its models.

The restrictions come as Anthropic approaches an IPO and investors scrutinize month-to-month growth deceleration. Revenue reached $4.7 billion in the first quarter, $11.6 billion in the second and $16.8 billion in the third. The first-quarter figure had already exceeded its total for all of 2025. Some investors have discussed an IPO valuation near $1.5 trillion, down from the roughly $2 trillion once expected. Cheaper, open-source Chinese models remain a concern for investors.

Technology and broader equity markets fell as investors weighed AI spending, oil prices and inflation risks. A nearly 7% plunge in chipmakers sent the Nasdaq 100 to its worst day since June, while the S&P 500 fell 1.2%. Meta Platforms’ plans to increase capital spending renewed concerns that technology companies would issue more debt to finance AI infrastructure.

James McCann of Edward Jones said investors were demanding stronger evidence of returns from AI investment and questioning whether spending was sustainable amid higher rates. Meta fell 5.6% despite better-than-expected third-quarter revenue. Chief financial officer Susan Li said expanding the user base of its AI agent Muse would require significant investment because of its computing intensity. She added that total serving costs would rise.

Markets fall as costs mount

In London, the FTSE 100 ended Thursday down 27.85 points, or 0.3%, at 10,725.03. The FTSE 250 fell 0.9% to 24,211.71, while the AIM All-Share lost 1.6% to 750.93. Paris’s CAC 40 fell 1.4%, and Frankfurt’s DAX 40 lost 1.1%.

AJ Bell investment director Russ Mould said concerns about the sustainability of AI spending hurt markets, while rising oil prices stoked inflation concerns. Nvidia chief executive Jensen Huang told CNBC demand for neoclouds was “off the charts.” But he said capital was scarce and impeding growth. Trade Nation analyst David Morrison said future commitments were enormous, while there was little clarity about when, or whether, planned spending would produce a return.

Brent crude stood at $111.18 a barrel at the London close, up from $109.14 at the same time Wednesday. The New York Times reported, citing sources, that the United States and Israel had plans for renewed strikes against Iran after next month’s U.S. midterm elections. President Donald Trump said Washington wasn’t negotiating with Tehran and that something would happen “fairly soon.”

A Salt Security survey of more than 380 security and technology professionals found that 86% of their organizations had at least one AI agent operating, and 77% had agents chaining actions across other agents. Only 18% said they could automatically stop an agent behaving unexpectedly; 13% could trace a complete path from instruction to outcome across every agent involved.