Tech-Led Rally Triggers 'Buy Sidecar' as Samsung and SK Hynix Surge on Semiconductor Supercycle Optimism

SEOUL — South Korea’s benchmark KOSPI index staged a historic rally on Wednesday morning, capturing the unprecedented 8,400-point milestone just a day after closing above the 8,000-point threshold for the first time. The explosive surge, driven by an aggressive tech-buying spree from foreign and institutional investors, triggered emergency market stabilization measures within minutes of the opening bell.

As of 9:02 a.m., the KOSPI stood at 8,447.69, marking a staggering gain of 400.18 points, or 4.97 percent, from the previous session. The index initially opened at 8,242.12, up 194.61 points (2.42 percent), before rapidly accelerating to an all-time intraday high of 8,450.26.

The sudden influx of buy orders forced the Korea Exchange (KRX) to activate a buy-side "sidecar" at 9:06 a.m., temporarily halting the execution of program-based buy orders for five minutes. This regulatory intervention occurs when the KOSPI 200 futures price fluctuates by more than 5 percent from the previous close for over a minute, signaling an extraordinary level of market enthusiasm.

Market analysts attributed the unprecedented rally to powerful tailwinds from Wall Street overnight. U.S. memory chipmaker Micron Technology witnessed a massive surge after major global financial institutions substantially upgraded its price target, validating a structural shift towards a high-margin semiconductor supercycle fueled by long-term artificial intelligence (AI) infrastructure agreements.

Domestic tech heavyweights immediately capitalized on this momentum, further amplified by the debut of new single-stock leveraged exchange-traded funds (ETFs) targeting Korea’s tech leaders. Market bellwether Samsung Electronics jumped 6.86 percent, returning to the historic 3 million won per share mark. Meanwhile, SK Hynix skyrocketed nearly 10 percent to maintain its 2 million won level, officially becoming the second domestic enterprise to cross the $1 trillion valuation threshold in market capitalization. Other tech-adjacent holding companies, such as SK Square, also registered double-digit gains.

However, the explosive growth on the main board highlighted a stark market polarization. While large-cap electronics and manufacturing sectors thrived, other industries like construction, bio-health, and automotive experienced minor pullbacks as liquidity shifted into semiconductors. Simultaneously, the tech-heavy KOSDAQ index trended in the opposite direction, trading at 1,163.75, down 8.77 points or 0.75 percent, due to intense institutional net selling outside the primary board.