South Korea's benchmark Kospi index has surged about 80% this year to record highs, yet its valuation has fallen to a historic low as corporate earnings, led by memory-chip giants Samsung Electronics and SK Hynix, have outpaced the rally. Investors remain divided over whether the cheap valuations present a buying opportunity or reflect concerns over the sustainability of the AI-driven memory boom.

The Korean bourse has swung more than 2,000 points between its intraday high and low over the last month

South Korea's benchmark Kospi index has surged about 80% this year to record highs, yet its valuation has fallen to a historic low as corporate earnings, led by memory-chip giants…