Why the Once-Soaring KOSPI Collapsed in a Single Day
The KOSPI (Korea Composite Stock Price Index) plunged more than 6% in a single day on the 6th, falling below the 5,000 mark intraday and triggering the circuit breaker, a mechanism that halts trading. The Democratic Party's landslide victory in the U.S. midterm elections raised the likelihood of stricter regulations on AI data centers. With the Democratic Party taking the position that AI investment is excessive, concerns emerged that the Trump administration's aggressive AI investment policy could be curtailed — prompting investors who had bought semiconductor stocks in anticipation of AI growth to dump their shares en masse. The sharp drop shows how swiftly political changes in the United States can have an immediate impact on the Korean market. It also demonstrated how quickly the value of assets invested in the AI industry can be shaken.
Uncertainty over AI investment proved to be the trigger. The KOSPI had climbed to around 9,000 four months earlier, only to fall nearly 50% in those four months. Investors holding stocks at the time suffered heavy losses. Stock prices reflect not only corporate earnings but also expectations of future growth. As expectations of AI industry growth had been driving up semiconductor stock prices, doubts about those expectations led investors to start selling, and the sharp decline is interpreted as the result of that shaken confidence.
The KOSPI is a representative index tracking the overall price movement of stocks listed on Korea's stock exchange, calculated with January 4, 1980 set as the base of 100. Because it is weighted by market capitalization, it is more heavily influenced by the movements of large-cap stocks, so the number of advancing and declining issues should be examined alongside the index value.
Foreign selling also deepened the index's decline. Foreign investors were reported to have sold a net total of about 10 trillion won worth of KOSPI stocks over the past week. Foreign capital is concentrated in large-cap names such as Samsung Electronics and SK Hynix, leaving the index directly exposed to blows. The price, not the volume of shares sold, was the problem: as selling pressure mounted, buy orders formed at progressively lower price levels, driving stock prices ever downward. On top of that, a complex mix of factors — global investor sentiment, exchange rates, interest rates, economic indicators such as the jobs report and consumer price index, and expectations for the semiconductor industry — combined to push the index lower.
The circuit breaker is a safeguard put in place by financial authorities to give investors time to assess the situation during sharp price swings, similar in concept to an electrical circuit breaker. However, stock prices do not necessarily rebound once trading resumes. The trigger itself is merely a signal that market anxiety has grown, and further declines are possible afterward. In reality, it remains unclear how much AI investment will shrink and what impact it will have on corporate earnings.
