South Korean stocks returned to negative terrain late Wednesday morning, offsetting earlier gains from the opening bell as foreigners and institutions both became net sellers.

The benchmark Korea Composite Stock Price Index (KOSPI) had fallen 6.61 points, or 0.4 percent, to 1,665.83 as of 11:20 a.m.

The market earlier rebounded as investors welcomed a set of additional stimulus packages being considered by the United States.

Washington announced Tuesday (local time) it is considering a stimulus package of US$1 trillion to cope with the economic fallout from the COVID-19 pandemic, including providing cash payments to its citizens.

Seoul shares, however, tumbled later in the session on concerns about the economic fallout from the COVID-19 outbreak.

The country added 93 new cases Wednesday, bringing the nation's total infections to 8,413, rising in the double digits for the fourth straight day.

Shares were mixed.

Market kingpin Samsung Electronics increased 0.63 percent, and No. 2 chipmaker SK hynix added 0.25 percent.

Carmakers traded lower, with Hyundai Motor falling 2.37 percent and its auto parts affiliate Hyundai Mobis slipping 4.59 percent.

Top steelmaker POSCO increased 0.64 percent, while Korea Zinc shed 5.09 percent. Hyundai Steel decreased 3.77 percent.

Naver, which operates the country's top online portal, advanced 1.32 percent, and its smaller rival Kakao gained 1.02 percent.

The local currency was trading at 1,237.90 won against the US dollar, up 5.60 won from the previous session's close. (Yonhap)