Fujikura Ltd., a leading Japanese optical fiber cable manufacturer, saw its shares tumble nearly 40% over four trading days following a disappointing earnings forecast. The company projected an operating profit of ¥315 billion for fiscal 2028, significantly below the ¥455 billion anticipated by analysts. This unexpected shortfall triggered a massive selloff, erasing approximately ¥5.6 trillion in market capitalization. The sharp decline in Fujikura's stock, which had previously surged over 400% in 2024 due to AI infrastructure demand, sent shockwaves through the market. The selloff extended beyond Fujikura, affecting other Japanese tech and AI-related stocks, as investors reassessed risks ahead of major earnings reports from industry giants like Nvidia. This dramatic repricing highlights the volatility and risk inherent in high-growth sectors.