Korean stocks tumbled Tuesday, with the benchmark index sliding below 8,000, as investors sold off shares despite another record earnings report from Samsung Electronics. According to the Korea Exchange, KOSPI closed at 7,656.31, down 4.91 percent from the previous session. Sell-the-news pressure weighed on the market after Samsung Electronics reported record preliminary earnings earlier in the day. The benchmark index plunged in the morning trading, triggering a sell-side sidecar for the 16th time this year. Losses deepened in the afternoon, setting off a circuit breaker — the sixth this year and the 12th in the index's history. Foreign investors led the sell-off, unloading 2.93 trillion won ($1.92 billion) worth of semiconductor, substrate, shipbuilding and defense shares. Institutional investors net sold 391 billion won, while retail investors bought a net 3.13 trillion won of shares. Chip stocks fell sharply on concerns that the semiconductor cycle may have peaked. Samsung Electronics dropped 6.92 percent, SK hynix lost 6.06 percent, SK Square slid 9.3 percent and Hanmi Semiconduct