An AI stock sell-off deepened Tuesday as Asian markets tumbled, with South Korea's Kospi temporarily halted after plunging more than 10 per cent and Tokyo's Nikkei 225 sliding 4 per cent. SK Hynix shares shed up to 10 per cent while Samsung Electronics fell over 12 per cent; the two firms account for about 40 per cent of the South Korean market.

In New York, SK Hynix American depositary receipts closed over 7 per cent lower at $143, and Nvidia dropped 5 per cent, allowing Apple to reclaim the title of world's most valuable listed company at $4.95tn versus Nvidia's $4.75tn. SK Hynix's Seoul-listed shares have now fallen roughly 45 per cent since their June peak above Won3mn, wiping about $570bn off its market value.

The sell-off reflects growing investor doubts about the durability of Big Tech spending on AI infrastructure. Although SK Hynix is expected to post record second-quarter operating profit of about Won64tn — up sevenfold year-on-year — concerns over future oversupply weigh on sentiment after Korean chipmakers unveiled aggressive expansion plans.

Analysts remain positive on the near-term outlook, citing long-term supply agreements. SK Hynix trades at just 4.4 times forward earnings, below Micron's 6.2 times, making it a "compelling buy" according to NH Investment & Securities as deleveraging nears completion.