Seoul shares plunged over 12 percent Wednesday to close below the 5,100-point mark amid growing concerns over the economic fallout from the Middle East conflict. The Korean won fell sharply against the U.S. dollar. The Korea Composite Stock Price Index (KOSPI) extended its losses, tumbling 698.37 points, or 12.06 percent, to close at 5,093.54, following a plunge of over 7.24 percent the previous session. The Korea Exchange (KRX) triggered circuit breakers shortly after the KOSPI fell more than 8 percent amid heightened geopolitical tensions. Institutions sold a net 579.4 billion won ($393 million) worth of stocks, offsetting foreigners and individuals' stock purchases of 228.78 billion won and 72.9 billion won, respectively. The Korean won was quoted at 1,476.20 won against the U.S. dollar at 3:30 p.m., down 10.1 won from the previous session's close.