Semiconductor Index Plunges 21% in July as AI Spending Bet Unravels

The one-way trade in semiconductor stocks that has defined equity markets for much of the past year is coming undone, triggering sharp volatility as investors question whether the surge in artificial intelligence spending can be sustained.

Scale of the decline

The Philadelphia Stock Exchange Semiconductor Index, known as the SOX, plunged 21% in July, according to market data, marking one of its steepest monthly drops in years after a prolonged rally driven by AI infrastructure demand.

• SOX index fell 21% over the course of July
• Decline follows a multi-year rally fuelled by AI chip demand
• Investors increasingly concerned that AI capital spending growth may slow

What analysts are saying

Market strategists said the sell-off reflects growing scrutiny of whether hyperscale cloud providers can continue to justify enormous capital expenditure on AI data centres, given uncertain near-term returns on that investment.

Some chipmakers have sought to reassure investors by pointing to strong order backlogs and continued demand from major cloud computing customers, but the broader market mood has turned more cautious.

Analysts said the coming earnings season for major chipmakers would be closely watched for signs of whether the AI infrastructure buildout is decelerating or merely pausing after an unusually rapid expansion.