(2nd LD) Seoul stocks spike nearly 6 pct on chip rally, eased U.S. bond yield concerns

Seoul's stocks surged nearly 6 percent on Thursday, driven by optimism surrounding chip giants Samsung Electronics and SK hynix, as well as a decline in U.S. bond yield concerns. The Korean won weakened against the U.S. dollar. The Korea Composite Stock Price Index (KOSPI) climbed 381.41 points, or 5.89 percent, to close at 6,852.58, following a peak of 6,904.55.

The index had plummeted by nearly 6 percent the prior day following a tech sell-off, but regained those losses after SK hynix unveiled a 40 trillion-won (US$28.7 billion) share buyback plan, and as speculation mounted about Samsung Electronics' forthcoming shareholder return policy. Program trading for KOSPI-listed shares was halted for five minutes around 10 a.m., as the Korea Exchange (KRX) deployed a buy-side sidecar following a 5 percent or greater rise in the KOSPI 200 Futures Index for at least one minute.

Previously, U.S. Treasury yields had rallied to their highest level since 2007, prompting a retreat in Wall Street's major indexes. However, the 30-year Treasury bond yield fell to its lowest in over a decade on Wednesday, alongside the benchmark 10-year Treasury yield. Trading was relatively light, with 301.74 million shares valued at 28.07 trillion won (US$20.15 billion), outpacing 518 advancers to 338 decliners.

Foreign investors bought a net 1.71 trillion won, while institutions and individuals sold net amounts of 487.37 billion won and 2.28 trillion won, respectively.

Analysts cited investors' renewed confidence in buying stocks, fueled by eased worries over rising U.S. Treasury yields. Samsung Electronics experienced a 9.49 percent increase, reaching 271,000 won, while its chipmaking rival SK hynix rose 12.73 percent to 1.69 million won. SK Square, the parent company of SK hynix, climbed 11.85 percent to 1.12 million won, and Samsung Electro-Mechanics, an electronics component subsidiary of Samsung Electronics, jumped 0.65 percent to 1.39 million won.

The Korean won closed at 1,392.6 won per U.S. dollar, down 5.1 won from the previous session's final price. Yield on three-year Treasurys increased by 1.3 basis points to 3.811 percent, whereas the return on benchmark five-year government bonds declined by 0.2 basis point to 4.066 percent.