South Korea’s tech-heavy Kospi dropped 10.8% on Tuesday to 6,023.66, its lowest level since April, as investors kept dumping chipmakers after a report that China’s semiconductor equipment push may be closing in on a tool long dominated by ASML. Trading was briefly halted by a circuit-breaker, Samsung Electronics sank 13.4%, and SK Hynix tumbled 14.7%, turning a fast-moving AI trade into one of the day’s sharpest market reversals.
The rout rippled well beyond Seoul. Japan’s Nikkei 225 fell 4% to 62,364.92, Taiwan’s Taiex dropped 4.7%, and TSMC slipped 3%. In the US, chip shares had already taken a hit on Monday, with AMD down 5.2%, Nvidia off 5%, and Micron lower by 2.3%. The pressure built after The Information reported that China’s Shanghai Yuliangsheng had begun mass production of homegrown deep ultraviolet lithography tools, a development that investors read as a direct challenge to the industry’s current hierarchy.
The message from markets was blunt: if China is making faster progress on chipmaking equipment, the valuation support under the global AI supply chain gets shakier fast. ASML shares fell 8.5% in Amsterdam on Monday after the DUV report, underscoring how quickly the shock spread from one equipment name to the rest of the sector. The move was especially violent in Asia, where chip stocks have become a proxy for the world’s enthusiasm around artificial intelligence spending, memory demand, and advanced manufacturing capacity.
Analysts said the sell-off was less about current earnings and more about what the report implied for future competition. “We believe the market was likely spooked by the progress of China’s chipmaking equipment capabilities, and was worried that this progress would threaten the competitive position of global chipmaking and chip equipment leaders,” said equity analyst Jing Jie Yu of Morningstar. Yu added, “That said, we believe the sell-off today is largely a knee-jerk reaction and overdone.”
That “knee-jerk” framing matters because the market reaction was not confined to one stock or one geography. It hit equipment makers, memory chip names, and the broader basket of companies that have ridden the AI buildout higher. The speed of the decline also showed how crowded the trade has become. When the same growth narrative supports valuations across multiple regions and subsectors, even one report about a technological advance can trigger a broad de-risking.
The timing made the move more explosive. South Korean chips had already been under strain after Chinese memory chipmaker CXMT surged 466% in its Shanghai STAR exchange trading debut on Monday, raising at least $8.6 billion. That debut fed the sense that Chinese competitors are not just talking about scale but are now pulling in capital at a pace that could support faster expansion. SK Hynix’s US-traded shares also closed below their $149 IPO price on Monday, ending the session at $143, a sign that sentiment had already turned fragile before Tuesday’s plunge in Seoul.
The market’s concern is not just today’s production numbers. It is the possibility that China’s chipmakers and equipment suppliers could shorten the gap in ways that pressure established leaders later. “The market’s concern lies less in CXMT’s current earnings and more in its potential for accelerated capacity expansion to rival Korean companies and technology development following its IPO,” said Kim Seok-hwan, market analyst at Mirae Asset Securities.
That logic helps explain why Samsung and SK Hynix were punished so severely. Both sit at the center of the global memory cycle, and both are tightly linked to the capital expenditure boom tied to AI servers and data centers. If investors start to believe that Chinese suppliers can build capacity faster than expected, the premium attached to the incumbents can compress quickly. The sell-off is also a reminder that the AI trade increasingly depends on geopolitical and industrial-policy assumptions, not just revenue growth.
Stephen Innes at SPI Asset Management captured that mood in more dramatic terms. “The AI trade spent the past several years behaving like a flywheel… Now that same wheel is beginning to throw investors off at speed,” he wrote. The line fits the day’s price action. Once the broad AI narrative stops acting like a one-way momentum engine, the same leverage that lifted chip stocks can work in reverse.
The slide also highlights a deeper tension in the sector. For years, investors have treated leading chipmakers and equipment suppliers as beneficiaries of a narrow, defensible technology stack. The report on Shanghai Yuliangsheng’s DUV production challenges that assumption by suggesting Chinese firms may be making progress in a segment that has long been associated with ASML’s dominance. Even if the advance is still early, markets are forward-looking, and they do not wait for earnings to confirm a threat before they reprice it.
The next test comes fast. Earnings reports this week from SK Hynix, Samsung, and Kioxia, along with US tech giants Microsoft, Meta, Apple, and Amazon, are expected to provide the next directional catalyst for the sector. That makes the current sell-off less like a single-day panic and more like a stress test ahead of a heavy calendar of corporate updates. If companies can show that AI-related demand remains intact, the damage may stabilize. If not, the selloff could keep spreading.
For now, the market is treating the AI boom with much more caution. The latest action suggests investors are no longer willing to assume every new development in chipmaking is bullish for the same set of winners. A report about Chinese equipment progress was enough to knock more than 10% off Korea’s benchmark index, send Samsung and SK Hynix sharply lower, and push weakness through Japan, Taiwan, Europe, and the US.
That is what makes this more than a routine sector dip. The AI rally has been one of the market’s strongest stories, but it is now colliding with the possibility that competition is intensifying faster than expected. Tuesday’s losses showed how quickly that story can flip when investors decide the next breakthrough may help rivals as much as incumbents.
