A financial data screen at Hana Bank headquarters in central Seoul shows the Kospi standing at 8,143.82 during trading on Friday. (Im Se-jun/The Korea Herald) South Korea's benchmark Kospi tumbled more than 5 percent in early trading Friday, tracking a sharp selloff in semiconductor stocks on Wall Street after Broadcom's earnings and outlook disappointed investors.The Kospi opened at 8,323.2, down 3.66 percent from the previous session. Losses deepened shortly after the opening bell, with the index falling to 8,190.25 as of 9:15 a.m., down 5.2 percent on-session. The decline pushed the benchmark below the 8,100 mark during trading.A sell-side sidecar was triggered at 9:08 a.m., temporarily halting program sell orders for five minutes to curb market volatility.Chipmakers led the decline: Samsung Electronics slid 6.4 percent to 329,000 won ($213), SK hynix plunged 8.18 percent to 2.11 million won.Other large-cap stocks followed suit. SK Square dropped 8.82 percent to 1.24 million won, while Hyundai Motor fell 5.29 percent to 663,000 won.Foreign investors were net sellers, offloading 564.8 billion won worth of shares on the main bourse. Institutional investors also sold a net 51.8 billion won, while retail investors were the sole net buyers, purchasing 580.3 billion won worth of stocks.The early selloff mirrored losses on Wall Street, where Broadcom shares plunged roughly 13 percent after the chipmaker reported fiscal second-quarter results and issued guidance that fell short of market expectations. The disappointment rippled through the semiconductor sector, triggering a broad-based selloff in chip stocks.