Semiconductor shares tumbled, with the Philadelphia Semiconductor Index dropping more than 12% over the past week. The slide reached an eighth straight day on Friday, putting the SOX on pace to equal its longest losing streak since 2006. The selloff has bled into major benchmarks too, with the S&P 500 on track for a 1.7% weekly drop - the worst since June - while the Nasdaq 100 is set to fall 5% for the week.
Drivers of the drop include concerns over higher interest rates, rich valuations, and hefty AI infrastructure outlays.
Investors shorting chip names have accumulated about $32 billion in unrealized gains over the past seven days, based on S3 Partners LLC data aggregated by Bloomberg. The damage spans the 30-member SOX, with all but 10 components having fallen more than 10% since the selloff started. Laggards include Coherent Corp., off nearly 30%, and Astera Labs Inc., Macom Technology Solutions Holdings Inc., and Credo Technology Group Holding Ltd., each down more than 20% over the eight-day slide.
Beyond semiconductors, shorts in CoreWeave Inc. stand to benefit as the company is poised for a drop of more than 20% this week, following a slide in its debt to levels typically associated with distress. For the AI cloud-computing firm, credit-default swaps suggest a default probability above 50% over the coming five years. Those short the name are on course for over $1 billion in mark-to-market gains this week.
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Some of the short interest reflects convertible bond arbitrage rather than purely directional bets, said Matthew Unterman, managing director at S3. Joe Tigay, who manages the Rational Equity Armor Fund, put it this way: "CoreWeave specifically is going to need a new story. It's going to need time to digest this new reality."
The retreat comes after a powerful advance earlier this year, when investors piled into firms expected to gain from hundreds of billions of dollars pledged for AI infrastructure capital spending. Memory-linked chipmakers led as demand for computing power ran into supply bottlenecks. Between the end of March and a record in June, the SOX more than doubled, boosting market value by roughly $6.5 trillion. As SLC Management's Dec Mullarkey said, "The run up in chips was very aggressive so invariably there was going to be some consolidation or pull back."
In plain English: a hot, AI-fueled trade met higher rate fears and rich valuations, and momentum flipped. That has created winners on the short side and sharp drawdowns across many chip names. If your exposure leans into semis or AI infrastructure plays, the current tape is a reminder that fast climbs can retrace just as quickly.
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