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)

Seoul stocks opened higher Thursday at a fresh high of over 6,700 as investors bet that chip demand will remain solid amid strong earnings from Samsung and US big tech giants.

The benchmark Korea Composite Stock Price Index had added 19.51 points, or 0.29 percent, to 6,710.41 as of 9:15 a.m. after rising as high as 6,739.39 at the opening bell.

The index closed at a new peak of 6,690.90 the previous day, extending its gains to a third consecutive day.

Overnight, major US indexes closed mixed, with the Dow Jones Industrial Average down 0.57 percent and the S&P 500 losing 0.04 percent, while the tech-heavy Nasdaq composite rose 0.04 percent.

The mixed results came as international oil prices rallied after US President Donald Trump said he will not lift a naval blockade of Iran until a nuclear deal is secured with Tehran, while investors were keeping an eye on earnings reports by tech giants, including Alphabet, Amazon.com, Meta Platforms and Microsoft.

After the US markets closed, all four companies reported stronger-than-expected revenue in the first quarter, reviving hopes for a continued artificial intelligence boom.

The Brent crude price, an international oil benchmark, spiked 6.1 percent to $118.03 per barrel, and the WTI price also jumped 6.95 percent to $106.88 per barrel.

The Kospi was boosted by blue-chip tech shares as Samsung Electronics, the world's leading memory chipmaker, posted record quarterly earnings in the first three months of this year, fueling hopes the industry will continue to enjoy fruits of the growth of the AI sector.

Samsung climbed 0.77 percent, and its chipmaking rival SK hynix advanced 1.62 percent. AI investment firm SK Square jumped 2.41 percent.

Major electrical firms Samsung Electro-Mechanics and LS Electric gained 1.09 percent and 1.65 percent, respectively.

But leading automaker Hyundai Motor started 0.72 percent lower.

Power plant manufacturer Doosan Enerbility was also down 0.77 percent, with major shipbuilder HD Hyundai Heavy losing 0.87 percent. Hanwha Ocean dropped 0.98 percent.

The Korean won was trading at 1,483.9 won against the US dollar at 9:15 a.m., down 4.9 won from the previous session. (Yonhap)