South Korea’s KOSPI sinks 5.28% as U.S. election results fuel AI regulation fears

South Korea’s benchmark stock index lost more than one-twentieth of its value on November 5, with Samsung Electronics and SK hynix falling even harder. The KOSPI closed down 5.28% as investors worried that Democratic gains in the U.S. midterm elections could bring tighter AI data-center regulation and slower investment.

The concern centered on the Congress taking control in January. Mirae Asset Securities analyst Kim Seok-hwan linked the retreat to Democrats gaining both chambers and the prospect of stronger oversight of AI data centers. That was an assessment of future political risk—not a newly announced restriction on construction or spending.

Selling triggers a five-minute trading curb

The KOSPI finished at 5,383.80, a loss of 300 points. It opened 1.82% lower and extended its decline through the morning. At 10:16 a.m., the exchange activated a sell-side “sidecar,” temporarily suspending program trading in KOSPI-listed shares for five minutes. The intervention applied to that trading mechanism, rather than all share trading.

The losses reached beyond the two largest chipmakers. Hanmi Semiconductor, a chip-equipment maker, fell 9.13%, while electronic-components supplier Samsung Electro-Mechanics dropped 15.34%. Those declines put several parts of the semiconductor supply chain under pressure in the same session, from chip production to equipment and components.

−7.57%Samsung Electronics

Samsung Electronics closed at 201,500 won after its decline.

−9.46%SK hynix

SK hynix finished at 1.26 million won, suffering the larger percentage loss of the two chipmakers.

Foreign investors sold a net 3.39 trillion won of South Korean shares. Institutions bought a net 841.8 billion won, while individual investors bought a net 2.28 trillion won. The split showed domestic buyers taking the opposite side of heavy foreign selling. DPA reported that foreign investors had now extended their selling streak to five sessions.

Trading volume was light at 256.8 million shares, worth 22.6 trillion won. Declining stocks outnumbered advancing ones by 534 to 344. Despite the index’s steep fall, the session was not a uniform retreat: those counts left a substantial group of shares moving higher even as semiconductor-linked companies recorded some of the sharpest losses.

The feared slowdown runs through data centers

DPA described the investment concern as a chain running from U.S. oversight to Asian suppliers. Investors feared that tighter regulation of AI development and data-center construction could slow capital spending—the money companies spend on long-term assets. Less investment in data centers could, in turn, weaken demand for semiconductors.

Japan’s equipment suppliers also fall sharply

The same concern hit Japanese companies supplying the semiconductor industry. Chip-testing equipment maker Advantest plunged 14.7%, and chipmaking-equipment supplier Tokyo Electron fell 9.4%. DPA attributed those losses to bets that Democrats could slow the pace of U.S. data-center expansion, connecting the Japanese declines to the policy expectations weighing on Seoul.

Japan’s major indexes nevertheless moved in different directions. The Nikkei average fell 1.79% to 61,077.90, while the broader Topix rose 1.16% to 3,940.39. That divergence is an important distinction in the regional picture: severe losses among AI-linked equipment suppliers occurred alongside gains in the broader Japanese market, rather than an across-the-board decline.