Seoul shares closed lower Thursday amid investors' disappointment on Micron Technology's earnings results. The local currency gained ground against the US dollar.

The benchmark Korea Composite Stock Price Index fell 7.99 points, or 0.29 percent, to 2,784.06.

Trade volume was moderate to a little slim at 387.4 million shares worth 10.1 trillion won ($7.3 billion), with losers far outnumbering winners 619 to 262.

Foreigners and retail investors purchased local shares worth 509.5 billion won and 264.4 billion won, respectively, offsetting institutions' sell-off of 774.3 billion won.

Overnight, Wall Street closed higher, mainly driven by megacap tech shares, but Micron Technology declined after earnings results failed to meet investors' expectations, with the artificial intelligence rally wavering in recent days.

"The Kospi started off weak on disappointment on Micron's earnings results, but narrowed earlier losses as auto and shipbuilding shares delivered a robust performance," Lee Jae-won, an analyst at Shinhan Securities, said.

Market bellwether Samsung Electronics rose 0.37 percent to 81,600 won, while No. 2 chipmaker SK hynix dropped 0.21 percent to 236,500 won.

Top automaker Hyundai Motor jumped 2.94 percent to 298,000 won, and its smaller affiliate Kia added 0.54 percent to 131,500 won to become the fifth-largest company on the Kospi.

Shipbuilders were also bullish, with HD Hyundai Heavy Industries up 2.62 percent to 156,400 won and HD Korea Shipbuilding & Offshore Industries up 4.65 percent to 157,500 won.

Biotech company SK Bioscience also soared 8 percent to 53,300 won after the company announced its plan to acquire German bio firm IDT Biologika.

But other big-cap shares were weak.

Leading battery marker LG Energy Solution dropped 0.91 percent to 328,000 won, and its smaller rival Samsung SDI retreated 2.17 percent to 361,000 won. Top chemical producer LG Chem also sank 2.27 percent to 344,000 won.

Internet portal operator Naver lost 1.78 percent to 165,400 won, and Kakao, the operator of the country's top mobile messenger, slid 2.88 percent to 40,400 won.

The local currency ended at 1,385.80 won against the US dollar, up 2.9 won from the previous session's close. (Yonhap)