South Korean shares opened lower Wednesday, as investor sentiment weakened over a deadlock in US fiscal stimulus plans and slow progress in new coronavirus vaccine development.

The benchmark Korea Composite Stock Price Index (KOSPI) fell 0.77 point, or 0.03 percent, to 2,402.38 in the first 15 minutes of trading.

Stocks traded bearish, taking a cue from Wall Street losses that stemmed from worries that the new US stimulus plan is losing steam ahead of the November presidential election.

Investor disappointment also grew, after COVID-19 vaccine developers, including Eli Lilly & Co. and J&J, halted their clinical tests due to safety concerns.

The Dow Jones Industrial Average lost 0.55 percent to close at 28,679.81 on Tuesday (New York time). The tech-laden Nasdaq Composite slipped 0.1 percent, and the S&P 500 lost 0.63 percent.

Market bellwether Samsung Electronics added 0.16 percent, with No. 2 chipmaker SK hynix advancing 0.68 percent.

Top pharmaceutical firm Samsung Biologics fell 0.83 percent, and Celltrion shed 1.29 percent.

Internet portal giant Naver gained 0.85 percent, with its rival Kakao edging up 0.13 percent.

Leading chemical maker LG Chem declined 1.09 percent, and rechargeable battery maker Samsung SDI dropped 0.45 percent.

Hyundai Motor, the country's largest automaker, climbed 0.84 percent, and top steelmaker Posco added 0.24 percent.

The local currency was trading at 1,147.55 won against the US dollar, down 0.45 won from the previous session's close. (Yonhap)