The AI selloff crosses the Pacific: Nikkei drops 2%, Kospi sinks 3% as data-center debt fears spread

• What: The AI infrastructure selloff spread from Wall Street to Asia; investors are repricing the cost of financing the AI buildout.
• When: Monday, October 19, 2026, Asian trading session (figures are intraday snapshots, not closes).
• Nikkei 225: down about 2% intraday, falling as much as 1,493 points at one point; chip names Taiyo Yuden −5.0%, Sumitomo Electric and Lasertec −4.9%.
• Kospi: down as much as 3.2% intraday, opening 3.17% lower at 5,488.41; Samsung Electronics and SK Hynix fell 4–6%.
• Rest of Asia: Taiwan's Taiex −1.5%, Shanghai Composite −0.55%; a Bloomberg gauge of Asian chipmakers slid more than 2% to its lowest since July.
• Backdrop: The Philadelphia Semiconductor Index fell 11.4% last week — its longest losing streak since 2008; the Kospi just logged its worst week since October 2008.
• Trigger: CoreWeave's share and bond selloff brought credit risks into focus; DeepSeek's cheaper V4.1-Flash model (Oct 17) raised memory-demand questions.

The selloff that started on Wall Street last week has crossed the Pacific. On Monday, Japan's Nikkei 225 slid about 2% and South Korea's Kospi dropped as much as 3.2% intraday, with chip giants Samsung Electronics and SK Hynix each down more than 4% at one point. The question now pricing itself into markets isn't whether AI demand exists — it's whether the debt financing the data-center boom will ever be repaid.

The move extends a brutal stretch. The Philadelphia Semiconductor Index fell 11.4% last week, its longest losing streak since 2008, after eight straight daily declines for US chipmakers ended Friday. The Kospi is coming off its worst week since October 2008, and the Nikkei shed 5.4% last week. Asia, which makes and equips the chips that AI runs on, is feeling the full force of the rethink.

What spooked the market

The proximate trigger was credit. Data-center provider CoreWeave's share and bond selloff brought credit risks into focus, Dow Jones reported Monday morning, and the unease has since spread across the AI value chain — even to companies with limited financing needs. Tiger Brokers analyst James Ooi told Dow Jones the selloff "suggests sentiment may be overtaking fundamentals," with investors rotating toward defensive sectors.

Two deeper worries are colliding. First, rising bond yields and widening corporate credit spreads are making the AI buildout's financing more expensive, while, as AMP economist My Bui put it, "AI infrastructure may need to be written down as it ages and depreciates in the meantime, which lowers book value massively." Second, a cheaper DeepSeek model — V4.1-Flash-1017, released October 17 — added a new question: whether future efficiency gains could slow the growth in memory demand, pressuring SK Hynix and Samsung. Bloomberg's gauge of Asian chipmakers slid more than 2% to its lowest since July.

The other side of the trade

Not everyone is convinced the correction is justified. Fresh earnings from key AI supply-chain players ASML and Taiwan Semiconductor last week showed that AI demand remains robust, and analysts note the Kospi is still up more than 30% this year after the AI spending boom pushed memory prices to record highs. China's economy even surprised slightly to the upside, with third-quarter GDP growing 4.5% versus 4.4% expected.

And in a sign the panic isn't universal, falling oil prices — Brent down 1.6% to $108.06 a barrel after Donald Trump waived some Russia sanctions — lifted US stock futures Monday morning, with S&P 500 futures up 0.5% and Nasdaq futures up 0.8%. But the intraday tape in Tokyo and Seoul told the sharper story: investors are now pricing the possibility that the AI trade's biggest risk isn't demand at all — it's the balance sheet behind it.

Sources: Dow Jones / Morningstar, Unbiased Headlines, Business Today, Global Economy Charts.