(ATTN: ADDS bond yields at bottom)

SEOUL, Aug. 19 (Yonhap) -- Seoul shares dipped nearly 6 percent Wednesday, led by steep losses in chipmakers, as rising oil prices and global bond yields dampened investor sentiment. The Korean won rose against the U.S. dollar.

The benchmark Korea Composite Stock Price Index (KOSPI) fell 398.66 points, or 5.8 percent, to close at 6,471.17, after touching an intra-day low of 6,400.81.

Shortly after the opening bell, program trading in KOSPI-listed shares was suspended for five minutes as the bourse operator activated a sell-side sidecar. The measure is triggered when the KOSPI 200 futures index falls 5 percent or more for at least one minute.

Overnight, Wall Street's major indexes closed lower, as stalled peace efforts between the United States and Iran weighed on investor sentiment and pushed oil prices higher.

The U.S. 30-year Treasury yield rose to its highest level since 2007 amid concerns that elevated energy prices could keep inflation high.

Trade volume was moderate at 302.07 million shares worth 22.94 trillion won (US$16.4 billion), with decliners far outnumbering advancers 700 to 171.

Foreigners and institutions sold a net 348.8 billion won and 132.4 billion won, respectively, while individuals bought a net 463.6 billion won.

"Foreign investors and institutions offloaded local semiconductor shares, including Samsung Electronics and SK hynix, amid renewed concerns over their outlook as bond yields rose," Lee Kyoung-min, an analyst at Daishin Securities, said.

In Seoul, chipmakers led the market decline.

Market bellwether Samsung Electronics plunged 7.82 percent to 247,500 won, and its chipmaking rival SK hynix tumbled 9.75 percent to 1.5 million won.

SK Square, the parent firm of SK hynix, sank 11.54 percent to 1 million won, and Samsung Electro-Mechanics, an electronics component affiliate of Samsung Electronics, decreased 3.68 percent to 1.38 million won.

Hanwha Aerospace rose 2.71 percent to 1,177,000 won following an announcement that its U.S. unit had won a contract to deliver K9 self-propelled howitzer prototypes to the U.S. Army.

The Korean won was quoted at 1,397.7 won per U.S. dollar as of 3:30 p.m., up 14.1 won from the close of the previous stock trading session.

Bond prices, which move inversely to yields, closed higher. The yield on three-year Treasurys lost 4.9 basis points to 3.798 percent, while the return on the benchmark five-year government bonds shed 4.2 basis points to 4.068 percent.

ejkim@yna.co.kr

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