Semiconductor equities surged roughly 70% through the first half of 2026, with the sector's index posting its best-ever 100-day start to a year. Memory specialists like Micron led the charge, with shares climbing over 870% year-on-year as AI training and inference demands pushed demand for high-bandwidth memory (HBM) and DDR5 chips well past historical peaks, according to Reuters.

The gains have been rooted in earnings strength. Samsung reported Q1 2026 operating profit of 57.2 trillion won—eight times the prior year—with its semiconductor division alone generating 81.7 trillion won in revenue, per CNBC. TSMC, the world's largest contract chip manufacturer, posted a 58% profit surge in 2026 after major cloud companies accelerated orders for AI accelerator chips. ASML, which supplies the specialized lithography equipment needed to make cutting-edge chips, raised its 2026 revenue forecast to 36–40 billion euros, Reuters reported, indicating that capacity expansions at leading foundries are running ahead of prior expectations.

As of late June 2026, chipmaker earnings continued to drive global equity gains, with the dollar near a one-year high, Reuters noted.

What deserves careful attention is the concentration of supply and market leverage embedded in these gains. TSMC alone holds 72% of global foundry market share and accounts for 41.5% of Taiwan's benchmark stock index—meaning a supply chain disruption to the Taiwan Strait would simultaneously crater chip capacity and the value of Taiwan's entire equity market. Samsung and SK Hynix together control 55% weighting in South Korea's KOSPI index. When two countries' national stock markets are this dependent on a handful of chipmakers, and when those chipmakers' demand flows almost entirely from a few U.S. cloud providers' AI spending plans, equity markets have become structurally vulnerable to a single pivot.

A slowdown in AI infrastructure spending—whether from macroeconomic weakness, disappointing quarterly results at a hyperscaler, or regulatory action—would pass directly through to chipmaker balance sheets and then to the index values of two of Asia's largest economies. The Wall Street Journal noted that the sector had added $5.7 trillion in market capitalisation through May, raising a natural question: how much of this rally reflects genuine future demand versus momentum pricing that leaves little room for setbacks?

That question lacks a definitive answer yet. Cloud providers' capital spending commitments remain on record trajectories for 2026 and into 2027, and ASML's guidance suggests chip equipment lead times have not yet compressed. But equity returns of 70–80% in a single half-year rarely come with margin for error. The market is pricing in years of sustained AI buildout. If evidence emerges that buildout is front-loaded—data centers built ahead of actual revenue-generating applications, or efficiency gains that reduce the number of chips per transaction—that repricing would likely be sharp and swift.