Wall Street Rallies on Chip Fever Even as a $489 Billion AI Debt Pile Rattles Investors

Wall Street pushed higher, powered once again by semiconductor stocks, even as fresh warnings about the mountain of debt underpinning the artificial-intelligence boom left investors uneasy about how long the rally can last.

The Dow Jones Industrial Average rose 0.7%, or 385.38 points, to close at 52,224.64. The tech-heavy Nasdaq Composite jumped 1.3%, or 329.13 points, to 25,837.21, while the S&P 500 added 0.9%, or 65.92 points, to finish at 7,509.20. Gains in chipmakers and the broader technology sector outweighed the drag from escalating conflict in the Middle East and the White House's latest tariff threats.

The day's standout was Super Micro Computer, whose shares rocketed more than 24% after the server maker said it expects its 2026 gross margins to roughly double — a signal that demand for the AI hardware it builds remains white-hot. Advanced Micro Devices climbed 1.5% to $552.33 after unveiling a $5 billion investment and a partnership with the AI company Anthropic to deploy its next-generation GPUs, deepening the arms race to supply the chips that train and run large AI models.

But beneath the euphoria ran a current of anxiety about how the boom is being financed. Goldman Sachs highlighted that roughly $489 billion in AI-related debt has been issued in 2026 alone, with the giant cloud "hyperscalers" accounting for about 40% of that borrowing. The figure crystallized a growing worry on trading desks: that the industry is taking on enormous leverage to fund data centers and chips well before the revenue to justify it has materialized. Analysts noted that a wave of AI-linked bond issuance now rivals the borrowing seen in past technology build-outs, and that any stumble in demand could leave companies servicing heavy debt against half-empty facilities.

Those concerns were sharpened after the closing bell. Alphabet, Google's parent, saw its shares slide about 3% in extended trading after it lifted its forecast for 2026 capital expenditures to as much as $205 billion, citing surging demand for AI. Investors have grown increasingly insistent that the hyperscalers show the intensive spending is actually driving revenue growth, rather than simply inflating costs, and Alphabet's guidance reignited that debate.

For now, the market's appetite for anything tied to artificial intelligence remains voracious, and the chip trade continues to lift the major indexes to fresh highs. But the widening gap between soaring valuations and the debt being piled up to sustain them has left even bullish investors watching for the moment the spending has to pay off — or the reckoning that could follow if it doesn't.