AI chip frenzy cooling? Three shocks behind the Philadelphia Semiconductor Index crash

In the early hours of July 8, Beijing time, the three major U.S. stock indices collectively declined. The Dow Jones Industrial Average fell 130.76 points (0.25%) to close at 52,925.15; the S&P 500 dropped 33.58 points (0.45%) to 7,503.85; and the Nasdaq Composite lost 302.47 points (1.16%) to 25,818.69. However, the most notable drop of the day came from the Philadelphia Semiconductor Index, which plunged 599.63 points, or 4.65%, to close at 12,300.52.

This decline was not an isolated event. Since hitting a phase peak on June 22, the Philadelphia Semiconductor Index has accumulated a drop of about 15%. In just a few trading days in July, the index fell an additional 13%. For an index that still holds a year-to-date gain of roughly 74%, the intensity and speed of this pullback have sparked widespread market debate over whether the AI chip bubble is bursting.

The divergence at the individual stock level further reveals the concentrated direction of selling pressure. Almost all components of the Philadelphia Semiconductor Index ended in the red, with only Nvidia rising 0.71% to $196.93. The biggest decliners were concentrated in high-valuation AI-related companies and semiconductor equipment sectors: Astera Labs plummeted 11.52%, Intel fell 9.66%, Teradyne dropped 9.59%, Marvell Technology lost 7.45%, KLA declined about 7.2%, and Advanced Micro Devices fell 6.51%. Memory chip stocks also came under pressure, with Micron Technology down 4.7% and SanDisk down 7.3%. TSMC's ADR fell $19.22 (4.25%) to close at $432.57.

Triple Resonance: Who Pulled the Trigger on the Philadelphia Semiconductor Index's Plunge

This sell-off was not triggered by a single factor but was the result of a triple logical resonance.

First Resonance: Samsung Electronics' "Good News Priced In"—The Better the Earnings, the More the Stock Falls. Samsung Electronics' second-quarter earnings report released that day showed operating profit reached 89.4 trillion Korean won, a historic high, benefiting from strong AI demand, and it expected the next quarter to double to 171 trillion Korean won. However, this "record" earnings report not only failed to boost market confidence but instead became the trigger for profit-taking—Samsung's stock plummeted over 7% in the Korean market that day, dragging the KOSPI index down nearly 5% in a single session. Anthony Saglimbene, chief market strategist at Ameriprise, noted that this earnings report was tantamount to "good news priced in" for investors—while the market has been continuously raising profit expectations, it has also begun to worry whether the massive AI construction investments can yield returns from real-world applications. Jose Torres, senior economist at Interactive Brokers, further stated that Samsung, Micron, and SK Hynix have become bellwethers for AI investment sentiment, with the three companies "symbolizing the high cost of AI construction." The surge in chip giants' profits has instead deepened market concerns about overinvestment in AI infrastructure.

Second Resonance: DeepSeek's Self-Developed Chips—The Computing Power Monopoly Narrative Faces a Challenge. Reuters reported that Chinese AI startup DeepSeek is developing its own AI chips, a move that could reduce the company's reliance on Nvidia and Huawei chips. This news marginally shook the market narrative that "AI computing power equals Nvidia GPUs"—if more cloud vendors and AI companies choose to develop their own chips or shift to ASIC routes, the current valuation system built around GPUs will face restructuring pressure. Notably, Marvell Technology—an ASIC chip maker named by Nvidia CEO Jensen Huang as the "next trillion-dollar company"—fell 7.45% that day, indicating that the market's pricing of "computing power diversification" is undergoing剧烈 volatility.

Third Resonance: Escalating Middle East Tensions Combined with Interest Rate Pressure—Systematic Cooling of Risk Appetite. U.S.-Iran tensions escalated again. The U.S. Treasury announced the revocation of sales licenses for Iranian oil, shortening the exemption period to July 17. Meanwhile, near the Strait of Hormuz, another ship attack was reported—Iran's Islamic Revolutionary Guard Corps fired missiles at two merchant ships and attacked a third with a drone. Brent crude oil futures rose by $4.36 (6.06%) in response, closing at $76.35 per barrel. The rebound in oil prices quickly revived inflation concerns, with the 10-year U.S. Treasury yield rising 5 basis points to 4.529%, marking a six-day consecutive increase—the longest streak since October 2024. Risk asset valuations came under pressure, with funds rotating from high-beta AI chip sectors into defensive sectors such as energy, healthcare, and real estate—that day, the S&P 500 energy sector rose 3.03%, healthcare rose 1.55%, and real estate rose 1.50%.

Bubble Burst or Healthy Pullback? A Logic Deduction from Four Dimensions

Faced with a 4.65% single-day drop and a 15% retracement from the peak, the market's core debate is: Is this the end of the AI chip bubble, or a healthy correction from excessive valuations?

Dimension One: Valuation Levels—Significantly Pulled Back from Extreme Highs, But Still Need Earnings Validation. As of early July, the Philadelphia Semiconductor Index's trailing twelve-month P/E ratio stood at about 43.9x, and its forward P/E at about 22.7x—essentially back to levels seen after the U.S.-Iran ceasefire agreement in early April, sitting at only the 48.3% and 16.9% percentiles since the start of this AI rally. From this perspective, the degree of valuation froth has notably converged from the June peak. However, the question lies in whether current valuations have fully priced in future earnings growth—market expectations for the full-year 2026 earnings growth rate of most core AI stocks in the U.S. are already lower than the year-over-year earnings growth rate for the 12 months prior to Q2 2025, with some stocks even expecting zero earnings growth.

Dimension Two: Industry Fundamentals—Revenue Continues to Expand, but Growth Slope Is Slowing. JPMorgan pointed out in its latest industry observation report that global semiconductor sales reached $131.9 billion in May 2026. If the second half of the year only grows according to historical seasonal patterns, global semiconductor revenue in 2026 is still expected to grow over 90% year-over-year, reaching between $1.5 trillion and $1.6 trillion. Nomura also warned that the AI semiconductor cycle is far from peaking, and the second half of 2026 may see "epic" supply chain mismatches, with shortages of components such as advanced packaging, PCB, and CCL pushing up prices and profit revisions as cloud vendor capital expenditures continue to expand. The fundamental logic on the demand side has yet to be falsified.

Dimension Three: Capital Expenditures and Overcapacity—A $1.5 Trillion Double-Edged Sword. Global cloud and AI infrastructure capital expenditures are projected to reach $1.5 trillion. This figure, on one hand, forms a solid floor for semiconductor industry revenue, but on the other, has sparked market concerns about "overinvestment." As large model parameters surge from hundreds of billions to trillions, the improvement in model performance has begun to plateau, while the electricity, depreciation, and maintenance costs required to keep these "pipelines" running are rising exponentially. Once the market begins to believe that computing power supply is growing faster than demand, the logic that has supported high valuations in the chip sector in the past will face challenges.

Dimension Four: Historical Reference—Essential Differences from the Internet Bubble. Zachary Hill, head of investment management at Horizon Investments, pointed out that after the frenzy in AI construction, semiconductor, and memory stocks, the market is rotating, and expectations for these companies "are already so high that they are almost impossible to surpass." However, J.D. Joyce, president of Joyce Wealth Management, also emphasized that the AI heat wave has not yet reached the point of a bubble bursting—the surge in semiconductor and AI stocks is still supported by simultaneous large profit increases, which is fundamentally different from the Internet bubble era when valuations existed without earnings.

Combining the above four dimensions, this Philadelphia Semiconductor Index decline is closer to an "expectation correction and capital rotation under high valuations" rather than a fundamental reversal of the AI chip industry logic. The 15% retracement from the June 22 peak is consistent with the median pullback level observed in previous technology and AI cycles. However, the premise for a "healthy pullback" is that the upcoming earnings season delivers on market expectations for earnings growth—if tech companies, especially hyperscalers, fail to surpass overly optimistic single-quarter estimates, it could trigger a larger correction.

Conclusion

The July 8, 2026, plunge in the Philadelphia Semiconductor Index was a stress test of multiple negative factors resonating together—Samsung's "good news priced in" triggered profit-taking, DeepSeek's self-developed chips shook the computing power monopoly narrative, and escalating Middle East tensions suppressed risk appetite. The triple logic convergence resulted in a dramatic single-day drop of 599.63 points.

But from a broader perspective, the global semiconductor industry cycle remains in an upward channel, with global semiconductor revenue in 2026 expected to exceed $1.5 trillion; the capital expenditure cycle driven by AI infrastructure construction is not yet over; and the forward valuation of the Philadelphia Semiconductor Index has retreated from extreme highs to mid-to-low historical percentiles. These fundamental factors provide support for the "healthy pullback" narrative.

The true watershed lies in the upcoming earnings season. If core AI stocks' earnings consistently beat expectations, this pullback will be defined as a normal correction under high valuations; conversely, if earnings growth fails to match the optimistic expectations already priced in by the market, the "bubble burst" narrative will gain more supporting evidence. For investors, the most important thing to distinguish now is not "how much it fell," but "what fell"—whether it's valuation compression or fundamental deterioration. The trading strategies corresponding to these two scenarios are entirely different.

FAQ

Q1: What are the main reasons for the Philadelphia Semiconductor Index's single-day plunge of 4.65%?

It was caused by a triple resonance of factors: Samsung Electronics' record earnings triggered "good news priced in" profit-taking, dragging down chip stocks across Asia and U.S. markets; a Reuters report that Chinese AI company DeepSeek is developing its own chips shook the Nvidia computing power monopoly narrative; escalating Middle East tensions pushed up oil prices and U.S. Treasury yields, systematically suppressing valuations of risk assets.

Q2: Is this Philadelphia Semiconductor Index decline a bubble burst in AI chips or a healthy pullback?

From a valuation perspective, the forward P/E of the Philadelphia Semiconductor Index has fallen from extreme highs to 22.7x, at the 16.9% percentile since the start of this rally; from a fundamental perspective, global semiconductor revenue in 2026 is expected to exceed $1.5 trillion. Currently, it is closer to an "expectation correction under high valuations," but the final judgment depends on earnings delivery in the upcoming earnings season.

Q3: Have the long-term fundamentals of the AI chip industry undergone a fundamental change?

Not yet. JPMorgan expects global semiconductor revenue in 2026 to grow over 90% year-over-year; Nomura believes the AI semiconductor cycle is far from peaking, with potential supply chain mismatches in the second half of the year. However, market concerns are rising about the growth rate of computing power demand and the efficiency of capital expenditures—these are the core sources of valuation pressure.

Q4: What key signals should be monitored going forward?

Focus on three directions: First, the tech earnings season starting in mid-to-late July, especially capital expenditure guidance and earnings expectations from hyperscalers; second, whether the Philadelphia Semiconductor Index can stabilize at key technical support levels; third, the trajectory of Middle East tensions and U.S. Treasury yields, which directly affect the valuation anchor of global risk assets.