South Korea’s stock market plunged more than 8% in a single day! KOSPI triggered the seventh circuit breaker of the year, with SK Hynix leading the declines, down 13%.

South Korea’s KOSPI index plunged more than 8% in a single day today, triggering the seventh circuit breaker of the year.
(Background: Goldman calls for South Korea’s Kospi index to rise to 12,000 points, revealing 3 major positives)
(Additional background: Goldman warns that global crude oil inventories have hit an eight-year low! The Hormuz-related ship catches fire, and Bitcoin has just reclaimed 80,000—bringing another stress test)

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• Time axis: Semiconductors lead the sell-off
• Clashes in the Strait of Hormuz ripple across the globe
• Seventh circuit breaker this year sets a new high

On Monday, July 13, the Korea Exchange (KRX) announced that due to a surge in the Middle East situation triggering a wave of selling, South Korea’s benchmark index KOSPI plunged more than 8% within just a few hours after the market opened. The exchange then immediately activated the circuit breaker mechanism, suspending all trading for 20 minutes.

According to live reporting by the Yonhap news agency, the circuit breaker was triggered at 1:28 p.m. local time (12:28 Beijing time). The reason was that KOSPI fell by more than 8% compared with the closing price of the previous trading day.

Time axis: Semiconductors lead the sell-off

Looking back at today’s market action, KOSPI was under pressure right from the open. Around 9:28 a.m., KOSPI was already down 4%, falling below the 7,200-point level. Memory chip leader SK hynix led the declines with an 8.3% drop, while Samsung Electronics also fell 4.2%.

Gains later widened into losses. At 12:15 p.m., South Korean stocks fell below 6,900 points, with an intraday decline of 7.75%. Then SK hynix slid more than 13% and retreated nearly 40% from its historical peak, while Samsung Electronics also tumbled more than 9%, dropping more than 30% from its June 19 high. By 1:28 p.m., the decline had broken through the 8% circuit-breaker threshold.

Clashes in the Strait of Hormuz ripple across the globe

The trigger behind this sell-off was a new round of clashes in the Strait of Hormuz reported by the Associated Press (AP). During the weekend, the United States and Iran launched attacks against each other, and both sides claimed they controlled the Strait of Hormuz, the world’s main artery for global energy supply.

The Strait of Hormuz is the necessary passageway for about 25% of the world’s crude oil shipments. Investment sentiment is affected accordingly, and global stock markets also came under simultaneous pressure. SBS Yonhap confirmed that KOSPI plunged more than 8% today and triggered the circuit breaker.

Seventh circuit breaker this year sets a new high

This is the Korea Exchange’s seventh time triggering the circuit breaker mechanism this year. Since the start of 2026, KOSPI has gone through multiple rounds of turbulence, including a major shake-up in chip stocks and a surge in crude oil prices. In June, Goldman also urged that South Korea’s KOSPI could rise to 12,000 points, but the actual market performance is clearly more volatile.

Of note is that today the Bank of Korea issued a report stating that the global semiconductor market still remains in a supply-demand imbalance. The AI-driven “super cycle” is expected to continue for some time, which also indirectly explains why memory stocks remain a focus even after big declines.

Not only South Korean stocks were affected today. In Asian trading, Bitcoin briefly fell below $63,000, and spot silver’s intraday decline also reached 3%, with global market sentiment staying cautious in parallel.

Market Watch: South Korea is a major semiconductor export country, accounting for over 50% of global memory chip production capacity. When KOSPI triggers a circuit breaker, it often signals a chain reaction in Asia’s technology sector. Investors should watch for possible spillover effects into Taiwan’s stock market and the Nikkei index.