Seoul: Seoul shares soared nearly 6 percent Thursday as investors bet on stronger shareholder returns from chip giants Samsung Electronics and SK hynix, and eased U.S. bond market concerns. The Korean won fell against the U.S. dollar. The benchmark Korea Composite Stock Price Index (KOSPI) rose 381.41 points, or 5.89 percent, to end at 6,852.58, after rising as high as 6,904.55.

According to Yonhap News Agency, the index had plunged nearly 6 percent in the previous session due to a tech sell-off but managed to recover the losses. The recovery was driven by SK hynix's announcement of a 40 trillion-won (US$28.7 billion) share buyback plan, while there was growing speculation about Samsung Electronics' forthcoming shareholder return policy announcement expected later this month.

A measure known as a buy-side sidecar was activated by the Korea Exchange (KRX) when the KOSPI 200 Futures Index rose 5 percent or more for at least one minute. This led to a five-minute suspension of program trading for KOSPI-listed shares at around 10 a.m.

On the international front, Wall Street's major indexes closed higher as U.S. Treasury yields retreated. This was after the Treasury Department announced plans to significantly increase buybacks of longer-term government debts. The yield on the 30-year Treasury bond, which had reached its highest level since 2007, fell on Wednesday, alongside the benchmark 10-year Treasury yield.