The KOSPI index opened sharply higher on June 25, driven by Micron Technology's strong earnings. It rose 5.61 percent to 8,945.95 by 9:15 a.m.
The Korea Exchange issued a buy-side sidecar at 9:07 a.m. after the KOSPI 200 Futures index rose more than 5 percent. Program trading was halted for five minutes.
Samsung Electronics gained 4.99 percent and SK hynix climbed 9.88 percent. SK Square rose 8.56 percent.
The Korean won traded at 1,547.95 won per dollar at 9:15 a.m., down 6.15 won from the prior session.
