Semiconductors powered a broad market rally on Tuesday, June 30, with AMD closing up 7.7% at $580.91, Marvell Technology gaining 7.3% to $297.89, Intel rising 6.0% to $139.63, and TSMC adding 4.9% to $477.57. The Philadelphia Semiconductor Index (SOX) climbed 4.3%.
The session capped a historic quarter for the sector. Micron surged 240% in Q2, Intel gained over 216%, and AMD nearly tripled. Combined, the three companies added roughly $2 trillion in market cap over the period. The SOX is up over 100% year-to-date, and semiconductor companies now account for a record 19.7% of the S&P 500, nearly quadruple their weight from mid-2020.
What's driving the move
The rally is backed by concrete capital expenditure, not hype. Hyperscalers, Amazon, Microsoft, Alphabet, Meta, are collectively spending an estimated $600–725 billion on AI infrastructure in 2026 alone: GPUs, high-bandwidth memory, networking chips, and data center buildouts. This is structural, not cyclical.
The second quarter also saw a clear rotation. While Nvidia, the dominant AI chipmaker, gained a relatively modest 15% in Q2, investors poured into the broader semiconductor ecosystem: memory makers, foundries, CPU/GPU rivals, and networking specialists. "The rotation out of AI hyperscalers into AI enablers has shifted investors' euphoria into semis, driving spectacular rallies," wrote Barclays analyst Anshul Gupta.
The contrarian voice
At the peak of the euphoria, Michael Burry, the investor who famously shorted the 2008 housing market, published a post on his Substack "Cassandra Unchained" warning that the chip rally is "the beginning of the end." He noted the SOX is trading roughly 65% above its 200-day moving average, a level not seen since March 2000, and put the index's price-to-sales ratio at over 16x, excluding Nvidia.
Burry disclosed new short positions via put options expiring January 2027 on the iShares Semiconductor ETF (SOXX), Nvidia, and Applied Materials, and added a first-time short on Caterpillar, a stock that has surged on AI-driven infrastructure enthusiasm.
"The SOXX itself is a pure form of overvaluation in an index, a form that is rarely seen and never so easily recognized as such," Burry wrote, adding that it's "only a matter of time" before a decline.
The morning after
Pre-market futures on July 1 point slightly lower, S&P 500 down 0.16%, Nasdaq down 0.4%. Semiconductor stocks are mixed in early pre-market trade. The question isn't whether the sector can keep rallying day after day, but whether current valuations, a 16x price-to-sales ratio on the chip index, already price in every piece of good news.
A historic quarter doesn't have to end in a crash. But when a seasoned bear speaks up, it's worth asking: how much of the AI story is already in the price?
