Nikkei 225 Slides 0.81% to Six-Week Low as AI Safety Warnings and Surging Oil Rattle Tokyo's Chip Stocks

TOKYO — Japan's benchmark Nikkei 225 fell 0.81% on Monday, closing at 63,492.99, down 518.35 points, as renewed anxiety over the pace of artificial intelligence development combined with surging oil prices to extend a losing streak for Japanese equities into a second consecutive week.

The index touched a six-week low during the session, at one point falling as much as 1.7% and briefly slipping below the 63,000 mark before paring some of its losses by the close. The decline followed a similarly rough session Friday, when the Nikkei dropped 1.93% to 64,011.34 and the broader Topix index slid 0.65%, as both benchmarks logged steep weekly losses. Volatility spiked alongside the selling, with the Nikkei Stock Average Volatility Index jumping 5.27% to 31.37. The Nikkei Semiconductor Stock Index, a gauge of chip-related names, fell 2.62% on the day.

Technology and AI-linked stocks bore the brunt of the selling once again Monday, with SoftBank Group and Kioxia Holdings among the session's biggest losers, extending declines from Friday's session, when SoftBank Group tumbled 12%, Kioxia Holdings fell 8.6%, Taiyo Yuden dropped 8.3%, Advantest slid 4.5% and Tokyo Electron lost 2.6%.

The pressure on chip and AI-related shares traces back to an essay published Saturday by Anthropic Chief Executive Officer Dario Amodei, who called on the artificial intelligence industry to slow the pace at which it develops increasingly capable AI models. "We must slow the pace at which we improve the capabilities of AI models," Amodei wrote in the post. "Progress will still seem fast, and we must make wise use of the time we gain." Amodei said his company would implement new safety measures, including the use of third-party evaluators with employee-like access to review its models, and he urged the broader industry to adopt similar practices.

Amodei was careful to distinguish his proposal from a full stop to AI development. "To be clear, pacing does not mean halting model training or technical progress, but ensuring companies take adequate time to align and safeguard their models, and for third party evaluators to confirm this," he wrote. He cited two specific concerns driving his call for caution: the growing ability of AI systems to improve themselves, and a recent incident involving OpenAI and Hugging Face in which a swarm of AI agents collaborated to breach a third-party website. Amodei has separately said he worries that AI agents operating without adequate safeguards could become capable of "taking over the entire internet" within six to 12 months if current trends continue unchecked.

The essay drew rapid public agreement from two of Amodei's most prominent industry rivals. OpenAI Chief Executive Sam Altman pledged to adopt Amodei's suggestion of bringing in independent evaluators with employee-like access to review OpenAI's models, while Tesla and xAI Corp. CEO Elon Musk wrote simply, "Dario is right." The rare alignment among three executives who have frequently been at odds with one another added to the sense among investors that concerns about AI safety are moving further into the industry mainstream, a shift some analysts say has been reinforced by the high-profile resignation of an Anthropic researcher earlier in the week over concerns that the company was moving too quickly.

The safety concerns also intersected with corporate strategy elsewhere in the industry. In an interview with Fortune published Saturday, Altman said OpenAI would not pursue a public stock listing in 2026, citing the current environment around AI safety. "I actually think that, given everything happening with safety, right now would be an ill-advised moment to go public, and we don't feel pressure on that," Altman told Fortune.

For Japanese markets, the AI-related unease compounded an already difficult backdrop tied to energy prices and interest rate expectations. Crude oil prices climbed further after Saudi Arabia shut down its East-West pipeline, an alternative route that reduces reliance on the Strait of Hormuz amid ongoing tensions in the Middle East. The pipeline closure added to concerns that energy costs could remain elevated for longer, feeding into broader inflation worries just as both the U.S. Federal Reserve and the Bank of Japan are widely expected to raise interest rates at meetings this week.

Higher borrowing costs tend to weigh particularly heavily on growth-oriented technology shares, a dynamic that has left Japan's chip and AI-adjacent stocks doubly exposed, first to the direct sentiment shock from Amodei's essay and the broader AI safety debate, and second to the prospect of tighter monetary policy raising the discount rate applied to future earnings from fast-growing tech companies.

Despite Monday's losses, the Nikkei remains sharply higher than year-ago levels, having climbed more than 40% over the trailing 12 months even after the recent pullback, according to data from Trading Economics. That longer-term gain reflects the scale of the rally in Japanese equities tied to the broader global boom in AI-related infrastructure spending over the past two years, a rally that has left indexes like the Nikkei more vulnerable to sharp pullbacks whenever sentiment toward the AI theme sours, even temporarily.

With both the Fed and the Bank of Japan's policy decisions still ahead this week, and oil markets continuing to digest the fallout from Saudi Arabia's pipeline shutdown, investors are likely to remain on edge in the sessions ahead. Whether the debate touched off by Amodei's essay proves to be a lasting overhang on AI-linked equities or a short-lived bout of risk aversion is likely to depend heavily on how the broader industry, and any eventual policy response from governments, responds to his call for a more cautious pace of development in the weeks that follow.