KOSPI Surges 3.68 Percent as Semiconductor Rally Triggers Sidecar

The Korea Exchange activated a buy-side sidecar on Wednesday, August 12, 2026, after a sharp rally in semiconductor stocks triggered a market volatility mechanism. The sidecar was activated at 11:57 a.m. because the KOSPI 200 Futures index rose more than 5 percent from the previous close and maintained that level for at least one minute, resulting in a five-minute suspension of program trading for KOSPI-listed shares.

The benchmark Korea Composite Stock Price Index (KOSPI) closed 3.68 percent higher, gaining 233.51 points to finish at 6,579.04. This marked the third consecutive session of gains for the index. The surge was led by major chipmakers Samsung Electronics and SK hynix, which both saw gains exceeding 5 percent. At the peak of the rally around 12:15 p.m., the KOSPI had risen 4.97 percent to 6,661.22 before settling at the closing price.

Foreign and institutional investors drove the market upward with net purchases of 2.83 trillion won and 527.7 billion won, respectively, while retail investors sold a net 3.19 trillion won. Other notable gains included SK Square, Samsung Electro-Mechanics, LG Energy Solution, and Hyundai Motor. The market rally coincided with a gain for the Korean won against the U.S. dollar and a decline in government bond yields.