Yesterday’s plunge and circuit breaker → today’s V-shaped rebound! Roller coaster in South Korea’s stock market as Samsung stock buyback, interest rate hike warnings, and MSCI negative news hit one after another.

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The South Korean stock market underwent an extreme repricing cycle within two days, experiencing a circuit-breaker-like plunge on Tuesday and a rapid rebound on Wednesday. However, the market’s core conflicts have not disappeared. AI profit expectations, policy risks, leveraged trading, and various rumors are simultaneously amplifying market volatility.

On Tuesday, the Korea Composite Stock Price Index (KOSPI) plummeted 10% in a single day and triggered a circuit breaker. Samsung Electronics and SK Hynix both tumbled over 12%, with these two companies together contributing to more than 70% of the index decline. The sell-off subsequently spilled over to the global semiconductor supply chain: Micron Technology fell 13% in one day, and Western Digital plunged 8.5%.

On Wednesday, the market saw a V-shaped recovery, but the rebound was unstable. KOSPI fell 1.5% during early trading but then rose 3.9%. Samsung Electronics dropped 3.2% before surging over 8%, while SK Hynix fell 4.5% before turning up 1%.

The news that Samsung may initiate a share buyback of nearly 90 trillion KRW became one of the most direct supports during trading. The Bank of Korea issued a warning about interest rate hike risks, MSCI continued to classify Korea as an emerging market, and the President's policy chief's statement that semiconductor companies should "share AI revenues" caused chip stocks to weaken again. For investors, the Korean market is shifting from simply trading AI growth to trading policy uncertainty and leveraged unwinding.

Black Tuesday: The AI Narrative Encountered Multiple Negative Resonances

The plunge on Tuesday was not triggered by a single event, but by multiple negatives concentrated in the same time window.

The initial shock came from expected AI hardware demand. Reports from Korean media that SK Hynix may slow down expansion of advanced AI memory chips undermined investor confidence in high-end memory prospects. Additionally, domestic discussions about taxing unrealized stock gains and regulatory warnings about overheating in leveraged ETFs intensified market concerns about the policy climate.

Analysts believe that the extreme volatility was driven more by mechanical algorithmic sell-offs, forced liquidations of retail leveraged funds, and institutional rebalancing, rather than sudden, dramatic changes in company fundamentals overnight. This also explains why the declines were so concentrated—Samsung Electronics and SK Hynix are both heavily weighted and central in AI trading. When AI expectations, policy discussions, and leverage risk all turn negative simultaneously, weighted stocks become the main outlet for liquidity withdrawal.

Wednesday’s Rebound: Samsung Buyback News Provides Short-term Support

Wednesday's rebound came first from emotional recovery after excessive declines, and next from the boost provided by Samsung Electronics' buyback news.

According to Yonhap News citing industry sources, Samsung Electronics plans to buy back about 90 trillion KRW worth of stock to pay special performance bonuses to its employees. The report stated that this arrangement came from an agreement between Samsung and labor unions, with the company granting bonuses in stock rather than cash. The post-tax estimated payment is about 93 trillion KRW, with more details to be announced soon.

Large-scale buybacks are usually seen by the market as a temporary support for the stock price and the supply-demand balance of circulating shares. After the news broke, Samsung Electronics surged by as much as 10% in early trading. However, this buyback is not in the traditional sense for shareholder returns, but is meant for employee bonus distribution, so its long-term valuation impact still needs to be reassessed by the market.

For KOSPI, Samsung's rebound is of index significance. As Samsung Electronics and SK Hynix have large weights in the index, their turnaround directly drove the main board rebound from early losses.

June 24 Intraday: A Statement on “Sharing AI Revenues” Again Triggers Sensitive Trading

Wednesday's V-shaped rebound quickly faced new policy signal challenges.

Famous financial blogger Jukan said Korea’s president's policy chief stated that Korean semiconductor companies should share AI-generated profits, causing semiconductor stocks in Korea to turn lower. The market reacted swiftly to such remarks because investors are concerned that future AI profit distributions may encounter further policy intervention.

This reaction shows that Korean chip stocks are currently being priced not just on AI demand and performance expectations, but also on high sensitivity to policy wording. For stocks with significant gains and high leveraged fund participation, any statement involving profit distribution, regulation, or taxation can amplify intraday volatility.

According to the Financial Times, KOSPI volatility has reached record highs. BNP Paribas Asset Management senior investment specialist Song Zhe said single-stock leveraged ETFs amplify volatility. Korea launched leveraged ETFs linked to hot stocks like Samsung Electronics and SK Hynix in late May, but Financial Supervisory Service chief Lee Chan-jin expressed regret on Monday about the “rushed” rollout of such ETFs.

Rate Hike Warning: The Central Bank Puts Financial Stability Risks Front and Center

The Bank of Korea said in its June 24 Financial Stability Report that given inflation pressure, economic trends, and financial stability risks, it is necessary to raise the benchmark interest rate at an appropriate time. The report points out that Korea’s financial system is generally stable but increased market volatility, rising Seoul home prices, leveraged asset investment causing financial imbalances, and worsened defaults in vulnerable sectors all pose risks.

The direct impact on the stock market is that rising rates increase financing costs and worsen repayment pressure for highly leveraged investors and weaker industry borrowers. The Bank of Korea listed construction, petrochemicals, and metals as structurally vulnerable sectors. These sectors account for 11.6% of total loans but their debt repayment capacity has significantly declined. The construction sector's interest coverage ratio dropped from 8.1 in 2021 to 1.0 last year, metals from 15.7 to 3.2, and petrochemicals from 14.1 to 1.3.

The report also noted that elderly self-employed and real estate lessors are risk points in a rising rate environment. Self-employed people aged 60 and above have average loans of 390 million KRW, higher than younger and middle-aged borrowers. Im Kwang-gyu, head of the BOK's Financial Stability Bureau, said that if competition intensifies or regional property markets deteriorate, defaults may rise and structural reform and enhanced monitoring are needed.

Financial stress indicators are also rising. Korea’s Financial Stress Index rose to 17.2 in the first quarter, above 16.3 in December 2025, and in the “attention” zone. The Financial Vulnerability Index rose to 46.0, exceeding the long-term average of 45.7. For the stock market, this means central bank policy discussions are moving from solely supporting growth to balancing inflation and financial stability.

MSCI Negative: Hope for Developed Market Watchlist Dashed

MSCI’s latest assessment also dampened expectations for foreign capital allocations. According to CNBC, MSCI on Tuesday continued to classify Korea as “emerging market” and did not include it in the developed market watchlist. This decision hurt expectations for Korea’s ultimate upgrade to developed market status.

MSCI stated that limited convertibility of the Korean won in offshore FX markets remains a key barrier to recategorization. It also mentioned Korea’s investor identification system remains rigid, physical transfer and OTC trading are restricted, and exchange data usage limitations affect investment product development. While Korea has announced a series of reforms, MSCI said investor feedback shows these issues are not fully resolved.

Korea’s Ministry of Finance said Korea was not included in this year's watchlist because some reforms are still underway, and implemented measures need more time to take effect. Bank of America Korea chief economist Benson Wu told CNBC the decision was not unexpected; Korea’s path to developed market status will be a “years-long” process.

The MSCI decision means expectations for correcting “Korea discount” are delayed. Korea plans to start 24-hour trading for the dollar-KRW spot market on July 6, its latest step toward FX market opening, but it’s insufficient to change MSCI classification in the short term.

Market Implication: Korean Stocks Enter “News-driven High Volatility” Stage

The current core contradiction in Korea’s stock market is the conflict between a strong AI narrative and highly leveraged trading structures.

Samsung’s buyback can bring short-term buying, the MSCI outcome affects long-term capital allocation, and the central bank’s rate hike comments change macro discounting. Together with semiconductor policy remarks and SK Hynix expansion reports, the market is simultaneously dealing with four variables: industry, policy, liquidity, and index funds.

This is why the market could crash and trigger a circuit breaker yesterday, only to rebound in a V-shape today. Price reactions are not linear, but are amplified by indexed stocks, leveraged ETFs, algorithmic trading, and retail funds.

Next, focus should not be on a single positive or negative event, but on how news items reinforce each other. Details of Samsung’s buyback, policy statements on AI profits for semiconductor firms, SK Hynix expansion expectations, leveraged ETF fund flows, progress on MSCI reforms, and the central bank’s interest rate path will all continue to affect Korean stock volatility.

A short-term rebound does not mean risks are cleared. Korea’s recent roller coaster market shows that in a crowded AI trade, rising policy uncertainty, and leveraged-product-driven volatility, the market’s sensitivity to every headline has markedly increased.

Risk warning and disclaimerThe market carries risks and investments should be made cautiously. This article does not constitute personal investment advice and does not take into account the specific investment goals, financial situation, or needs of individual users. Users should determine whether any opinions, views, or conclusions in this article fit their particular situations. Any investment made based on this article is at the user’s own risk. ```