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

South Korean stocks opened sharply lower Tuesday as investors await a potential deal in high-stakes tariff talks with the United States, with just three days remaining before the negotiation deadline.

The benchmark Korea Composite Stock Price Index shed 24.34 point, or 0.76 percent, to 3,185.18 in the first 15 minutes of trading.

Last-minute negotiations are under way between Seoul and Washington to reach a deal on the US President Donald Trump administration's aggressive tariff scheme before the Aug. 1 deadline.

Finance Minister Koo Yun-cheol was scheduled to depart for Washington later in the day to meet with Treasury Secretary Scott Bessent.

In a rare move, Industry Minister Kim Jung-kwan and Trade Minister Yeo Han-koo have even traveled to Scotland to engage with their US counterparts, US Commerce Secretary Howard Lutnick and Trade Representative Jamieson Greer, who have been accompanying Trump on his state visit to the UK.

Most top-cap shares traded lower.

Market bellwether Samsung Electronics fell 1.21 percent following sharp gains in the previous session, while chip giant SK hynix lost 1.91 percent.

Leading battery maker LG Energy Solution shed 0.26 percent, and chemical giant LG Chem tumbled 3.04 percent.

Carmakers opened lower. Top automaker Hyundai Motor declined 1.37 percent, and its sister affiliate Kia edged down 0.19 percent.

But defense giant Hanwha Aerospace rose 1.26 percent, and leading financial firm KB Financial advanced 1.18 percent.

Top online portal operator Naver climbed 1.17 percent, while leading steelmaker Posco dove 3.41 percent.

The local currency was trading at 1,391.65 won against the greenback at 9:15 a.m., down 9.65 won from the previous session. (Yonhap)