South Korean stocks ended 0.62 percent lower Wednesday as investors took a breather following a recent rally that sent the main stock index to a yearly high, analysts said. The Korean won shot up against the U.S. dollar.

The benchmark Korea Composite Stock Price Index slumped 12.58 points to 2,028.45. Trading volume was heavy at 523 million shares worth 5.2 trillion won ($4.7 billion), with gainers outnumbering decliners 423 to 395.

"Overnight losses on Wall Street, as well as recent gains, prompted investors to step to the sidelines. It also seems that investors are waiting to see how Samsung Electronics' first-quarter earnings turn out," said Han Yo-seop, an analyst at KDB Daewoo Securities Co.

The KOSPI has been climbing higher as investors bet on a global easing wave. The index closed at 2,042.81 on March 25, the highest this year.

Samsung Electronics, the country's biggest market-cap firm, is expected to release its first-quarter earnings estimate next week.

Analysts forecast the tech behemoth to post an operating profit of 5.41 trillion won in the three-month period, up 2.4 percent from the previous quarter, according to the median estimate compiled by market tracker WISEfn.

Large caps mostly ended in negative territory. Samsung Electronics fell 1.25 percent to 1,423,000 won and top automaker Hyundai Motor retreated 2.67 percent to 164,000 won.

POSCO fell 2.66 percent to 238,000 won amid ongoing probes into alleged slush funds at its construction unit POSCO Engineering & Construction. Media reports that Warren Buffet's Berkshire Hathaway Inc. sold its entire stake in the steel giant also fanned investor concerns on sluggish earnings.

In contrast, food conglomerate Orion jumped 4.06 percent to 1,205,000 won on anticipation that its overseas business will shore up sales. Meritz Securities projected the company's profit to grow in the mid-10 percent range this year, buoyed by growing sales in China.

Oil refiners outperformed the market, with No. 3 S-Oil gaining 3.73 percent to 66,700 won and industry leader SK Innovation rising 3.25 percent to 98,500 won.

The local currency ended at 1,102.4 won against the U.S. dollar, up 7.1 won from Tuesday's close.

Bond prices, which move inversely to yields, closed mixed. The yield on three-year Treasurys slipped 0.1 basis point to 1.720 percent, while the return on the benchmark five-year government bonds ticked up 0.1 basis point to 1.803 percent. (Yonhap)