Some investors took to the sidelines ahead of a speech by Federal Reserve Chair Janet Yellen later in the day. Yellen is set to deliver a speech in London on global economic issues.

Kim Dae-jun, a senior researcher at Hankook Investment & Securities, said individual investors have poured their money into technology stocks, such as Samsung Electronics and SK hynix, on expectations over their healthier second-quarter earnings.

Samsung Electronics rose 0.04 percent to end at 2,415,000 won, and SK hynix, a global chipmaker, gained 2.52 percent to 69,200 won.

Naver, the operator of the country's top Internet portal, shed 2.14 percent to 869,000 won.

Automakers traded in negative terrain, with industry leader Hyundai Motor down 2.13 percent to 160,500 won and its smaller affiliate Kia Motors dipping 1.68 percent to 38,000 won.

The local currency closed at 1,136.90 won against the US dollar, up 0.2 won from the previous session's close. 

Bond prices, which move inversely to yields, closed higher. The yield on three-year Treasurys fell 0.5 basis point to 1.681 percent and the return on the benchmark five-year government bond was flat at 1.853 percent. (Yonhap)