An electronic board showing the Korea Composite Stock Price Index at a dealing room of the Hana Bank headquarters in Seoul on Thursday. (Yonhap)
An electronic board showing the Korea Composite Stock Price Index at a dealing room of the Hana Bank headquarters in Seoul on Thursday. (Yonhap)

South Korean stocks opened weaker Thursday as investors took profit following strong gains in the previous session despite an overnight rally on Wall Street.

The benchmark Korea Composite Stock Price Index shed 10.06 points, or 0.39 percent, to 2,537.00 in the first 15 minutes of trading.

Overnight, US stocks were buoyed by optimism surrounding joint artificial intelligence investments by OpenAI, Oracle and SoftBank, which was touted by President Donald Trump.

The S&P 500 rose 0.61 percent, reaching its highest level in over a month, while the Dow Jones Industrial Average and Nasdaq climbed 0.30 percent and 1.28 percent, respectively.

In contrast, Seoul shares lost ground, led by losses among chipmakers.

Market heavyweight Samsung Electronics plummeted 1.29 percent, while chip rival SK hynix plunged 2.88 percent despite having reported stellar earnings before the opening of the market.

Automotive and steel shares also retreated. Leading automaker Hyundai Motor and Kia declined 0.24 percent and 0.1 percent, respectively. Top steelmaker Posco Holdings fell 2.08 percent.

Bio-related shares, meanwhile, advanced, with industry leader Samsung Biologics surging 5.03 percent after reporting record earnings in the previous session.

The local currency was trading at 1,436.65 won against the US dollar at 9:15 a.m., up 0.95 won from the previous session. (Yonhap)