South Korean stocks faced their second trading suspension this week as semiconductor shares collapsed, with the benchmark Kospi dropping as much as 9% and triggering a 20-minute halt on the Korea Exchange. Samsung Electronics and SK Hynix each tumbled more than 10% at their worst points, erasing Thursday's gains driven by Micron's upbeat outlook.

Foreign investors dumped 3 trillion won ($1.9 billion) in Kospi shares during morning trading alone. The dramatic reversal stems from growing concerns about Apple Inc.'s memory chip shortage forcing price hikes, while rumors swirl that OpenAI may postpone its IPO. These factors have intensified anxiety over whether the artificial intelligence investment boom can sustain momentum.

The market's extreme volatility reflects surging retail participation through margin trading and leveraged exchange-traded funds tracking chipmakers. Five of eleven circuit breakers since 2000 have activated this year alone, creating swings reminiscent of meme-stock mania. Both Samsung and SK Hynix are poised to announce hundreds of billions in new investment spending.

Analysts warn that while the memory trade remains viable, broader headwinds pose risks. The market is pricing in potential slowdowns to the AI trade as the memory cycle peaks, making volatility likely to persist amid leveraged positioning.