South Korea’s Kospi Posts Record One-Day Surge Amid AI-Driven Tech Rally

On July 31 2026, South Korea’s benchmark KOSPI index surged in a single session, posting gains reported between 14 % and 18 % by different outlets. The rally was led by memory-chip makers Samsung Electronics and SK Hynix, whose shares climbed roughly 20-30 % across reports.

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The surge followed a three-day rout that erased more than 17 % of the index’s value earlier in the week. Investors had dumped AI-linked stocks amid fears of a valuation bubble and competition from Chinese chipmakers. On July 31 2026, regulators introduced stricter cash-deposit requirements for leveraged-ETF investors, raising the minimum deposit from 10 million won to 30 million won, a move cited as a factor that helped reposition capital toward the rally.

Kospi jumps on U.S. chip rally as AI optimism returns

• Index performance: gains range from 14 % to 18 %.

Kospi jumps on U.S. chip rally as AI optimism returns

• Share price moves: Samsung Electronics rose between 20 % and 28 %; SK Hynix advanced between 25 % and 30 %.

South Korea’s Kospi Index Rebounds Over 17%, SK Hynix Surges Near 30%, Samsung Electronics Soars 23%

• Foreign buying: net foreign inflows of 4.86 trillion won (? $3.38 billion) by 11 a.m. on the rally day.

Kospi jumps on U.S. chip rally as AI optimism returns

• Leverage unwind: assets in leveraged ETFs targeting South Korea fell from about $50 billion at the end of June to $17 billion after deleveraging.

Japan, South Korea Stocks Rally as KOSPI Surges 13%, SK Hynix Jumps Over 27%, Samsung Gains 22%

South Korean regulators announced the new cash-deposit threshold on July 31 2026, emphasizing that the rule aims to curb excessive risk without halting market activity. The Korea Exchange activated its “sidecar” mechanism and temporarily suspended program trading for five minutes to temper volatility.

Japan, South Korea Stocks Rally as KOSPI Surges 13%, SK Hynix Jumps Over 27%, Samsung Gains 22%

SK Group Chairman Chey Tae-won disclosed a personal purchase of 3,620 SK Hynix shares on July 30 2026, a move interpreted as a confidence signal for the memory-chip maker.

South Korea’s Kospi Index Rebounds Over 17%, SK Hynix Surges Near 30%, Samsung Electronics Soars 23%

Sources differ on the exact magnitude of the rally and the closing level of the KOSPI:

Kospi jumps on U.S. chip rally as AI optimism returns

The variation reflects differing measurement points (intraday peak vs. closing price) and the rapid pace of price changes during the session. No source provided a definitive post-close figure, leaving the exact final level unconfirmed.

AI surges violently! Samsung and SK Hynix soar 25%, Korean stocks jump over 14%, SoftBank soars 15%, Japanese stocks surge

The rally underscores how tightly South Korea’s equity market is linked to global AI spending. Positive earnings from U.S. tech giants—particularly Microsoft’s stronger-than-expected quarterly results—re-ignited confidence in AI infrastructure demand, directly benefiting Samsung and SK Hynix.

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Analysts note that while AI-related fundamentals remain solid, “short-term distortions in trading dynamics” could keep volatility elevated. The episode also illustrates the regional spillover effect, with Japan’s Nikkei and Taiwan’s Taiex posting gains of 4-8 % as investors chased the AI narrative across Asian markets.

Japan, South Korea Stocks Rally as KOSPI Surges 13%, SK Hynix Jumps Over 27%, Samsung Gains 22%

Overall, the July 31 surge demonstrates the dual nature of the AI-driven market—rapid upside when sentiment turns positive, but equally swift downside when doubts re-emerge—making the KOSPI a bellwether for global AI capital flows.

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