This photo, taken Tuesday, shows the trading room of Hana Bank in Seoul as South Korean stocks plunged by nearly five percent on tech stock losses. Photo by Yonhap

Seoul shares plummeted nearly 5 percent Tuesday as technology stocks extended losses after Samsung Electronics Co. released its preliminary second-quarter earnings estimate. The Korean won fell against the U.S. dollar.

After opening 1.6 percent lower, the benchmark Korea Composite Stock Price Index (KOSPI) extended losses, falling 395.02 points, or 4.91 percent, to close at 7,656.31.

Trade volume was heavy at 512.29 million shares worth 39.66 trillion won (US$25.9 billion), with decliners outnumbering gainers 509 to 358.

Institutions and foreigners sold a net 309.1 billion won and 2.92 trillion won worth of stocks, respectively, while individuals purchased a net 3.13 trillion won.