SEOUL — In an extraordinary display of market momentum that shattered all historical precedents, South Korea’s benchmark KOSPI index staged a spectacular rally on Friday, surging nearly 18 percent in a single trading session to comfortably reclaim the 6,500-point landmark. The staggering jump represents the largest single-day point gain and percentage surge in the history of the nation's capital markets, eclipsing records set during the global financial crisis nearly two decades ago.

According to official market data provided by the Korea Exchange (KRX), the KOSPI closed at 6,595.45, up a mind-boggling 1,001.89 points, or 17.91 percent, from the previous day's close. Trading began on a hyper-bullish note, triggering a buy-side sidecar circuit breaker within the opening minutes as the index jumped over 8 percent almost instantaneously. Momentum accelerated steadily throughout the afternoon session, driven by relentless buying in large-cap technology and semiconductor heavyweights.

The day’s extraordinary 17.91 percent rise completely eclipsed the previous historic record of 11.95 percent set on October 30, 2008, during the height of the global liquidity crunch. The junior, tech-heavy KOSDAQ index similarly experienced explosive gains, jumping 74.98 points, or 11.63 percent, to settle at 719.76. In the foreign exchange market, the Korean Won showed modest stabilization against the US dollar, with the USD/KRW exchange rate dropping slightly to close at 1,424.75 won.

Tech Titans Lead the Onslaught

The record-breaking rally was overwhelmingly anchored by the nation's premier technology conglomerates, several of which touched their daily upper limit price caps (30 percent limit). Memory chip giant Samsung Electronics spiked by an astonishing 26.8 percent to close at 262,500 won. SK Hynix, a key supplier of high-bandwidth memory (HBM) chips, locked in at its daily price ceiling, surging 29.95 percent to finish at 1,718,000 won.

Other major holding companies and electronic component manufacturers surged in tandem, with SK Square and Samsung Electro-Mechanics both rocketing by 29.9 percent. The collective market capitalization of these tech behemoths expanded by hundreds of billions of dollars within hours, underscoring the deep concentration of capital into AI supply chain leaders.

Global Drivers & Market Dynamics

Market analysts attributed the explosive rebound to a drastic reversal in global sentiment surrounding artificial intelligence (AI) capital expenditure and corporate earnings. Fears of an impending AI bubble and reduced tech capital spending—which had severely dragged down global markets in recent sessions—were dramatically alleviated overnight following blockbuster quarterly results from Microsoft and a powerful resurgence in US chipmakers such as Micron Technology (+18.3%) and SanDisk (+25.9%).

Domestic institutional and foreign investors seized upon the renewed tech optimism, initiating aggressive net-buying programs. Foreign investors unleashed an unprecedented buying spree on the Main Board, purchasing a net 7.1821 trillion won ($5.05 billion) worth of equities, while domestic institutional investors added 1.1783 trillion won in net purchases.

Conversely, retail investors used the dramatic spike as an immediate opportunity to realize profits and exit levered positions. Retail market participants recorded a massive net selling figure of 8.2543 trillion won, representing one of the largest single-day retail sell-offs on record.

Regulatory Impact & Financial Sector Action

The market fireworks coincided with the official implementation of tighter regulation regarding single-stock leveraged product margin requirements. The newly introduced rule increases mandatory deposit ratios for single-stock leverage trading aimed at curbing excessive speculation during volatile periods. Market regulators reported that trading volume in single-stock leveraged products dropped slightly on the first day of implementation, though experts noted that full regulatory impact would require several days to assess accurately.

In response to the extreme volatility, major financial investment firms in Seoul initiated voluntary stabilization measures, including dispersing leverage asset rebalancing transactions across trading hours rather than clustering orders at market close. Analysts expect these structural adjustments, combined with renewed global tech momentum, to stabilize market microstructure over the coming weeks.