Why South Korea's Stock Rout Is Dragging Down U.S. Chip Stocks Even After Strong Earnings

Strong Chip Results Get Overwhelmed by a Korean Bear Market

Taiwan Semiconductor Manufacturing Co. (TSM) and ASML Holding both delivered strong quarterly numbers, with revenue guidance raised sharply and analysts hiking fair value estimates in response. TSM increased its 2026 capex budget by $8 billion to $62 billion—a 15% jump—while signaling that 2027 capacity is already booked and 2028 capacity is starting to fill. Morningstar analysts lifted their TSM fair value to $534 per ADR and boosted ASML’s to $2,050 per share, citing unexpected long‑term demand visibility.

Yet both stocks pulled back after the earnings releases. According to Morningstar’s commentary, the market had already priced in exceptional second‑half growth, leaving investors to wrestle with a wide range of 2028 forecasts. But there was another force at work: an overheated South Korean stock market that tipped into a bear market and triggered forced selling.

The Korean market, where over 50% of market capitalization is concentrated in just two semiconductor memory names, had been on a tear for two years. It peaked a few weeks ago, then tumbled roughly 25% from its high—technically a bear market. The slide unleashed a wave of margin calls, leading to forced liquidations that spilled into U.S.‑listed chip stocks, including TSM and ASML, even though the fundamental picture had improved.

How Korea’s Mega-Caps and Margin Calls Hit Global Semiconductor Trading

Why Strong Earnings Weren’t Enough

Even with TSM projecting revenue growth above 40% this year and ASML’s capex increase pointing to sustained expansion, the shares fell because near‑term optimism was already baked into prices. The real debate now is about 2028 revenue and earnings, where assumptions vary widely. That uncertainty, combined with the Korean overhang, created a disconnect between fundamentals and share‑price movements.

The Spillover from Korea’s Two‑Stock Market

South Korea’s equity market is uniquely fragile. With two memory chip giants representing more than half of market cap, any downdraft in those names can quickly turn into a broader rout. Stocks had doubled over the past year, fueled by speculative momentum. When the peak arrived, forced selling from margin accounts did not stay confined to Seoul. Correlated trading and sector‑wide sentiment transmitted the selling pressure to U.S. semiconductor stocks, dampening the post‑earnings reaction that would normally follow such strong guidance and fair value upgrades.

A Short‑Term Dislocation, Not a Fundamental Warning

Morningstar’s analysis suggests the sell‑off is technical, not a reflection of slowing demand. The capacity increases and the fact that 2027 output is already committed argue that the underlying business is robust. The Korean market, while down 25% from its top, is still up 50% year to date—and it doubled over the prior 52 weeks. That kind of overheated rally leaves room for further deleveraging, but it does not alter the multi‑year demand story for advanced chips and the equipment needed to produce them.

What the Sell-Off Means for Investors Watching TSM and ASML

For investors tracking these names, the Korean volatility creates a few concrete considerations:

• Forced selling from margin calls is a price‑dislocation event, not a permanent change in TSM’s or ASML’s earnings power. Once the overhang clears, the gap between current prices and Morningstar’s fair value estimates—$534 for TSM, $2,050 for ASML—may begin to close.
• The concentration risk in Korea’s market means that further unwinding could periodically weigh on global chip stocks, even when the business outlook is improving. Position sizing should account for this cross‑border correlation.
• The key signal to watch is stabilization in Seoul’s trading volumes and a reduction in forced selling; that could be the first sign that the technical pressure on U.S. chip shares is fading and that fundamentals are regaining the upper hand.