Investors are showing signs of unease over the AI-fueled stock market surge after industry leaders called for a slowdown in development, sparking worries that the massive capital expenditures underpinning the rally could dry up. However, some argue that clearer safety guardrails could ultimately benefit the long-term growth of the AI sector.

This nervousness comes on the heels of a series of stark warnings about AI's potential threat to humanity. AI industry leaders, including Anthropic CEO Dario Amodei, urged over the weekend for a deceleration in development pace to allow more time for managing risks. OpenAI's Sam Altman and SpaceX's Elon Musk expressed support for stronger regulation. Conversely, the CEOs of Microsoft and Meta opposed slowing down development.

Tech giants are pouring billions into AI data centers, benefiting numerous companies and their stock prices, which has helped the S&P 500 more than double since the bull market began in October 2022. Wall Street has been on alert for signs that such spending could lose momentum, with projections estimating these outlays could approach $800 billion by 2026.

"If we actually see order cancellations, data center and construction deal cancellations, that becomes a problem," said Chuck Carlson, CEO of Horizon Investment Services. "I need to see concrete evidence of a slowdown, not just talk." If leading AI developers like OpenAI and Anthropic are forced to decelerate, their valuations could face added pressure as both companies prepare for public listings. Carlson believes that once these firms eventually go public, "shareholders will demand they continue to grow and expand."

Ed Yardeni, president of Yardeni Research, sought to downplay AI slowdown concerns on Monday. He argued that the weekend calls for a slowdown may be more about establishing safety measures rather than cutting capital spending. As technology becomes more powerful, stronger guardrails might become necessary, but this does not necessarily undermine the investment cycle. He also pointed to productivity data supporting the AI-driven growth narrative, maintaining that the economy remains in a "productivity-driven technology boom," and kept his year-end S&P 500 target of 8,400 points.

So far this year, the S&P 500 has gained more than 11%, largely driven by corporate profit growth fueled by heavy spending over the past few years. According to BofA Global Research, AI hyperscalers including Microsoft, Alphabet, Amazon, Meta, and Oracle are expected to spend approximately $795 billion on capital expenditures this year, approaching $1.08 trillion by 2027. Most of this spending flows to semiconductor companies, whose stocks and profits have surged this year but faced selling pressure on Monday. Despite this, the Philadelphia Semiconductor Index is still up nearly 60% year-to-date in 2026.

"The market is punishing the 'picks and shovels' players more than the hyperscalers because that sector is most vulnerable to a slowdown in AI development pace," said Eric Klatz, Chief Investment Officer and co-head of wealth at Arena Private Wealth. However, Klatz noted that stricter scrutiny of industry safety could offer a silver lining. "Construction processes won't stop just because CEOs ask for safety guardrails. Quite the opposite—if there's a credible safety framework, long-term capital spending might actually be easier to fund."

The recent market volatility reminds some investors of the turmoil in early 2025 triggered by China's DeepSeek AI model, which raised doubts about the pace of AI infrastructure spending. That selloff proved to be a brief blip in the AI trade. Yet investors are now weighing broader risks, including the possibility of increased government regulation, even though President Donald Trump on Monday called AI safety threats a "hoax" and downplayed the need for oversight.

"The real risk isn't a slowdown in development pace, but regulatory overreaction," Klatz said. Michael Bruun, global co-head of private equity for Goldman Sachs Alternatives, noted that investors are trying to determine "whether regulation will tighten or loosen, whether geopolitical tensions will escalate or ease, and whether a new paradigm will emerge in the technology sector."

If AI concerns intensify, the stock market could become vulnerable, as both the S&P 500 and the Nasdaq Composite sit only about 2% below their record highs, while the market faces challenges including rising bond yields, higher oil prices, and the possibility of a Fed rate hike this week to curb inflation.

"AI semiconductor and infrastructure stocks have already priced in a sustained capital expenditure boom, leaving almost no room for error in dealing with the industry imposing limits on itself," said James Humphreys, managing partner at Mindset Wealth Management. "If the market faces more stubborn inflation than expected and an unclear Fed rate path, then cutting off the market's main growth engine would expose the broader indices completely to these macroeconomic headwinds."