Ngày thứ Ba đen tối của thị trường chứng khoán Nhật Bản và Hàn Quốc: Hàn Quốc kích hoạt cắt mạch, Nikkei giảm mạnh, cơn sốt AI bước vào giai đoạn điều chỉnh

Original by Odaily Planet Daily (@OdailyChina)

Author | Qin Xiaofeng (@QinXiaofeng 888 )

Today, Asian stock markets experienced sharp volatility.

South Korea's KOSPI index plunged over 8% intraday, triggering the market's circuit breaker mechanism and suspending trading for 20 minutes; it eventually closed nearly 10% lower at 8203.84 points, marking the third-largest single-day drop of the year. Japan's stock market also came under pressure, with the Nikkei 225 index falling about 3.5% to close near 69,788 points, ending an eight-day winning streak; the TOPIX index fell about 2.6%.

The adjustment hit technology stocks, particularly the semiconductor sector, the hardest. Heavyweights like Samsung Electronics and SK Hynix led the decline, dragging down the entire market. Foreign capital accelerated its sell-off, trading volume surged significantly, and market panic sentiment clearly intensified.

Since June, stock markets in Japan and South Korea have experienced multiple severe fluctuations, with Korean stocks triggering circuit breakers four times this year. Previously driven by the AI and semiconductor boom, the KOSPI had approached its all-time high of 9385 points; the Nikkei 225 had also briefly stood above the 70,000-point mark. In just a few weeks, the shift from record highs to significant pullbacks highlights market fragility and profit-taking pressure. Odaily Planet Daily will analyze this from three aspects: market performance, underlying causes, and future trends.

1. Market Plunge: From All-Time Highs to Circuit Breaker Alerts

Opening on June 23, the KOSPI started high at 9083.54 points and briefly surged to 9175.45 points during the session. However, following selling by foreign investors and herd selling, the index rapidly plummeted. Around 2:33 PM, the decline exceeded 8%, triggering the Korea Exchange (KRX) circuit breaker mechanism, suspending trading in all KOSPI constituent stocks for 20 minutes. Similar mechanisms had been activated on multiple days previously, such as June 5 and 8, indicating that volatility has become the norm.

At the close, the KOSPI stood at 8203.84 points, a single-day drop of 9.99%, with trading volume surging to 48.371 billion shares. Semiconductor giants like SK Hynix and Samsung Electronics led the losses, each falling over 12%. South Korea's KOSDAQ index showed even greater fragility, simultaneously dropping over 6%, with small-cap tech stocks falling broadly. Net selling by foreign investors was significant, becoming the main source of selling pressure.

The Japanese market reaction was relatively milder but still noteworthy. The Nikkei 225 index fell over 3% intraday, closing at approximately 69,788 points, a single-day drop of about 3.47%, with the TOPIX also retreating. Tech and semiconductor-related stocks performed the worst: SoftBank Group fell over 10%, chip manufacturer Kioxia plunged 15.1%, and Tokyo Electron dropped 6.2%. The AI and semiconductor sectors that had previously driven the Nikkei's rally experienced a broad correction, ending an eight-session winning streak.

Compared to recent highs, the magnitude of this adjustment is astonishing. The KOSPI has fallen over 12% from its mid-June peak, and the Nikkei 225 has significantly corrected from above the 70,000-point level.

Global market linkages were evident. US tech stocks came under collective pressure overnight, with the Nasdaq falling over 1% and the S&P 500 edging lower. Rotation occurred within the "Magnificent Seven," with Amazon, Meta, and other stocks leading the decline. Other Asian markets, such as Taiwan, were also affected, creating a regional sell-off in tech stocks.

Overall, this is a rapid and severe adjustment led by the tech sector, with South Korean stocks suffering far greater declines than Japanese stocks due to their high concentration.

2. Cause Analysis: A Phased Burst of the AI Bubble under Multiple Factors

The sharp decline in Japanese and South Korean stock markets is the result of multiple factors, which can be analyzed from aspects such as immediate triggers, macro-policy pressures, and structural risks.

1. Immediate Triggers: Weakness in US Tech Stocks Overnight and Profit-Taking Pressure

A significant pullback in US tech stocks on the previous trading day directly transmitted to Asian markets. The Nasdaq fell over 1.2%, with notable rotation within the Magnificent Seven and pressure on some individual stocks.

Lisa Shalett, Chief Investment Officer (CIO) of Morgan Stanley Wealth Management, pointed out: "Rotation within the Magnificent Seven is evident, and news of departures by some executives or researchers has intensified market concerns about the pace of AI commercialization. Investors are starting to demand more evidence that massive AI capital expenditures can translate into sustainable profitability."

This concern quickly spread to the Japanese and South Korean markets, which are highly dependent on the global AI supply chain. South Korea's semiconductor exports consistently account for over 20% of total exports, with Samsung Electronics and SK Hynix together holding about a 40% weight in the KOSPI. On June 23, these two giants fell roughly 8%-12%, directly dragging down the index.

Furthermore, Japanese and South Korean stock markets had accumulated substantial gains since June, resulting in hefty profit-taking positions. The KOSPI index surged from around 5,000 points at the start of the year to above 9,000 points by mid-June, with a maximum year-to-date gain of over 80%. The Nikkei 225 index also rose from around 40,000 points at the start of the year to above 70,000 points, setting a record high. With valuations at elevated levels (the KOSPI's forward P/E ratio briefly approached historical highs), any negative catalyst could easily trigger profit-taking. The concentrated selling on June 23 was a natural correction following the excessively rapid prior gains.

2. Macro and Policy Factors: Rising Expectations of Fed Rate Hikes and Impact of Economic Data

Strong US employment data continues to fuel market expectations that the Federal Reserve will maintain high interest rates or even raise them further. According to a Reuters report, non-farm payrolls increased by 172,000 in May, far exceeding economists' forecast of 85,000, while the unemployment rate stabilized at 4.3%. This data prompted some institutions, such as Goldman Sachs, to push back their first rate cut expectations to 2027. More critically, the Fed's FOMC meeting on June 16-17 decided to keep the federal funds rate unchanged in the 3.5%-3.75% range. The meeting statement emphasized that economic activity is expanding steadily, but uncertainty arising from the Middle East conflict has increased, and inflation remains above the 2% target.

The Fed's latest dot plot released a clear hawkish signal: the median forecast for the federal funds rate at the end of 2026 was raised to 3.8% (a significant increase of 0.4 percentage points from the 3.4% forecast in March), suggesting at least one rate hike is possible within the year. Additionally, the FOMC raised its inflation forecast for 2026: the median core PCE inflation forecast rose to 3.3%, and the overall PCE forecast rose to 3.6% (both previously around 2.7%); the GDP growth forecast was slightly lowered to 2.2%.

Interest rate-sensitive growth stocks, especially in the tech and semiconductor sectors, bore the brunt. South Korean stocks, previously viewed as typical "high-beta" assets due to the AI frenzy, are extremely sensitive to changes in global liquidity. Japanese stocks are also constrained by global liquidity expectations, although improved domestic wage growth data provides some support.

This series of macro signals significantly pushed up US Treasury yields and put pressure on global risk assets, directly exacerbating the selling pressure on Japanese and South Korean tech stocks.

3. Structural Risks: Excessive Market Concentration and Foreign Capital Outflows

The structural vulnerability of South Korea's stock market is particularly prominent. The KOSPI is highly dependent on the two semiconductor giants, Samsung Electronics and SK Hynix. Any fluctuation in the semiconductor cycle or global AI demand leads to sharp index swings.

Sustained foreign capital outflows are another key factor. Foreign investors, who had accumulated significant profits during the prior rally, have engaged in net selling several times since June, especially in Korean stocks. Some funds may have rotated into US IPOs (like SpaceX) or other assets. On June 23, net selling by foreign investors scaled up significantly, becoming the main source of selling pressure.

In contrast, while Japan's market was also dragged down by tech stocks, its sector diversification is relatively higher, limiting the Nikkei 225's decline to around 3.5%.

Additionally, specific company developments intensified market pressure. According to market news, SK Hynix recently adjusted its capacity allocation for AI memory chips (especially HBM), shifting some production lines to more profitable traditional DRAM to optimize short-term earnings. This move raised investor concerns about the short-term supply-demand balance for HBM, triggering selling.

3. Future Outlook: Short-Term Volatility Inevitable, Long-Term AI Narrative Remains Resilient

Looking ahead, Japanese and South Korean stock markets will exhibit characteristics of "consolidation amid volatility and structural divergence." Short-term market volatility will remain elevated, but medium-to-long-term fundamental support persists, and the correction itself provides a window to accumulate high-quality assets.

Short-term volatility dominates; recovery depends on US stocks and Fed signals. In the short term, the market remains in a high-volatility adjustment phase. The performance of US tech stocks is a key barometer. If the Nasdaq stabilizes or sees a technical bounce, Japanese and South Korean markets are likely to follow suit with a recovery. Conversely, if the Fed releases further hawkish signals or Q2 corporate earnings in Japan and South Korea disappoint, the correction could extend or deepen. Key events to watch include:

• US inflation (CPI/PCE) and employment data for June-July;
• The next FOMC meeting (July);
• Q2 earnings results from heavyweights like Samsung Electronics, SK Hynix, and Tokyo Electron.

Strong medium-to-long-term fundamentals; corrections are opportunities. Global AI capital expenditures continue to grow rapidly, and the fundamental logic of the semiconductor super-cycle remains unchanged. According to forecasts by Goldman Sachs and other institutions, cumulative global AI-related capital expenditures (computing, data centers, power) from 2026 to 2031 will total approximately $7.6 trillion. AI CapEx alone in 2026 is expected to be close to $765 billion, rising annually to $1.6 trillion by 2031. New data center capacity is projected to add nearly 100 GW between 2026 and 2030, with total investment reaching the $3 trillion level.

South Korea maintains a strong leading position in HBM (High Bandwidth Memory) and advanced manufacturing processes. SK Hynix's HBM market share has consistently remained between 50% and 62%, and its supply share for the NVIDIA Rubin platform in the HBM4 era could reach around 70%; Samsung Electronics is also accelerating capacity expansion, planning to increase HBM capacity by about 50% in 2026. Long-term orders for these two giants are essentially secured through 2027, indicating the AI memory demand super-cycle is still in its early stages.

From a long-term perspective, AI remains a productivity tool capable of reshaping the world order, and periodic adjustments are unlikely to reverse the major trend of technological progress. Just like corrections following past technology bubbles, they ultimately left substantial rewards for true infrastructure builders and innovators. This "Black Tuesday" might mark the inflection point where AI investment transitions from frenzy to rationality, from concept to industry. The resilience and potential of Japanese and South Korean stock markets remain worthy of anticipation.