South Korea’s benchmark KOSPI index cratered more than 8% on June 23, forcing two separate circuit-breaker halts in a single trading day. The selloff, driven by a rout in US technology stocks and rising Treasury yields, erased billions in market value and knocked Samsung Electronics from its top spot on the KOSPI for the first time in 26 years.
Circuit breakers hit twice
The KOSPI opened at 9,083.54 and slid steadily before hitting an 8.11% drop to 8,375.31 by the close. The first circuit breaker kicked in at 11:40 a.m., pausing all trading for 20 minutes. A second halt followed around 2:40 p.m. as the selloff deepened. Foreign investors were net sellers throughout the session, adding to the downward pressure.
Japan’s Nikkei 225 also broke an eight-session winning streak, falling nearly 3%. Benchmarks in Taiwan, South Korea, and Japan had each climbed at least 40% this year before the sudden reversal.
Tech weakness spreads from the US
The trigger for the panic was a broad decline in US technology shares. Alphabet fell 4.99% after two AI researchers left the company, while SpaceX dropped 16% following a bond offering. The so-called Magnificent Seven stocks — a group of mega-cap US tech names — took a collective hit, and their weakness rippled through Asian markets overnight.
Analyst Han Ji-young said the combination of Magnificent Seven weakness and rising Treasury yields weighed heavily on growth stocks. Han noted that falling oil prices could partially cushion the rate burden, but that didn’t stop the selloff on June 23.
Market leaders lose ground
Samsung Electronics, long the largest stock on the KOSPI by market capitalization, fell 8.77% to 322,500 won. That drop pushed Samsung behind SK Hynix in market-cap ranking for the first time in 26 years. SK Hynix itself fell 11.55% to 2.582 million won, even though US memory-chip maker Micron surged 6.82% overnight — a divergence that puzzled traders.
The semiconductor sector, a pillar of South Korea’s export-driven economy, took the brunt of the losses. Investors appeared to be revaluing chip stocks after months of relentless gains.
Oil prices could soften the blow
Han Ji-young pointed out that falling oil prices might provide a partial buffer, reducing input costs for energy-intensive industries and potentially easing the burden from higher interest rates. But that silver lining did little to stem the day’s panic. The question now is whether the circuit-breaker halts will give traders enough time to reassess, or whether the rout has further to run.
The KOSPI’s double-halt session is the most dramatic since the 2020 pandemic crash. With foreign investors still net sellers and US tech jitters unresolved, the next few trading sessions will test whether South Korea’s market can stabilize on its own.
