"The recent rally was largely driven by domestic-focused issues, which is quite unprecedented given that blue chip exporters usually have led a bull market. But it's doubtful these stocks will keep up because their investors are mostly institutions, not foreigners who have far more clout in terms of the KOSPI's gains," said Seo Jung-hun, an analyst at Samsung Securities Co.

Offshore investors finished the session with a net purchase of 8.17 billion won, with individuals also scooping up a net 161.3 billion won. But institutional investors sold off a net 218.7 billion won.

Insurers and steelmakers led the marginal decline. Top insurer Samsung Life Insurance retreated 3.25 percent to 119,000 won, and No. 1 steelmaker POSCO fell 0.92 percent to 270,500 won. 

In contrast, retailers gathered ground on growing hopes that China's hostile policy stemming from a diplomatic dispute with Korea over a US anti-missile system may be coming to an end.

Lotte Shopping, the operator of Lotte Group's department store and hypermarket units, jumped 2.58 percent to 278,000 won.

Netmarble Games, a top mobile game developer that went public last Friday, plunged 7.69 percent to 144,000 won, after its rival NC Soft on Tuesday unveiled its new mobile game slated for a June release. NC Soft finished up 4.46 percent to 374,500 won.

The local currency ended at 1,118.30 won against the greenback, down 2.3 won from Tuesday's close. 

Bond prices, which move inversely to yields, closed higher. The yield on three-year Treasurys shed 3.3 basis points to 1.684 percent and the return on the benchmark five-year government bonds fell 4.1 basis points to 1.901 percent. (Yonhap)