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Kospi Jumped 3.1% and the Nikkei 1.7% on Anthropic's IPO Filing. Why China's Markets Sat It Out
- South Korea's Kospi closed up 3.1% at 5,638.34 on October 27, after briefly gaining more than 4%. The exchange triggered a sidecar, a temporary halt on program trading.
- The Kospi had fallen 18.2% over the previous month. Samsung Electronics rose 4.2% and SK Hynix 5.2%.
- South Korea's economy grew 3.4% from a year earlier in the third quarter of 2026.
- Japan's Nikkei 225 rose 1.7% to 63,268.37. Advantest jumped nearly 9% and SoftBank Group about 5%.
- Hong Kong's Hang Seng fell 0.7% and China's CSI 300 fell 1.3%.
What happened
Asian markets mostly rallied on Tuesday, October 27, a day after Anthropic publicly filed for a Nasdaq IPO. Chip stocks led. But the rally split the region in two.
| Market | Move (Oct. 27) | Close |
|---|---|---|
| South Korea (Kospi) | +3.1% | 5,638.34 |
| Japan (Nikkei 225) | +1.7% | 63,268.37 |
| Australia (S&P/ASX 200) | +0.4% | — |
| India (Nifty 50) | +0.1% | — |
| Singapore (STI) | −0.1% | — |
| Hong Kong (Hang Seng) | −0.7% | — |
| China (CSI 300) | −1.3% | — |
Source: Fortune, AP, October 27, 2026.
Korea: a sharp rebound after a sharp fall
The Kospi gained more than 4% at one point and closed up 3.1%. The move was big enough to trigger a sidecar, a brief halt on program trading that kicks in when futures swing sharply.
The bounce came off a deep hole. The Kospi had dropped 18.2% in the previous month as worries grew about AI spending and memory chip prices. Our earlier analysis covered the Kospi bear market and the AI memory trade.
Samsung Electronics rose 4.2% and SK Hynix 5.2%. Both make the high-bandwidth memory used in AI data centres, so a large, well-funded AI company heading to the public market is a direct read-through to their order books.
Korea also got good economic news: third-quarter GDP grew 3.4% from a year earlier, helped by chip exports.
Japan: chip-equipment makers soar
In Tokyo, Advantest, which makes chip-testing equipment, jumped nearly 9%. SoftBank Group, a major AI investor, rose about 5%, and Tokyo Electron about 3%. The Nikkei is now above 63,000.
The Bank of Japan meets this week, with a hold at 1.25% expected. See our BOJ preview.
China: outside the AI supply chain
Mainland China and Hong Kong went the other way. The CSI 300 fell 1.3% and the Hang Seng 0.7%. Chinese AI chip designer Cambricon fell 5.7% and SMIC 1.3%.
Alicia Garcia Herrero, chief Asia-Pacific economist at Natixis, told Fortune the reason is structural: Hong Kong and mainland markets "sit outside the main U.S. AI supply chain." US export controls keep the most advanced chips out of China, and Chinese users already have cheaper home-grown AI models like DeepSeek.
In other words, a US AI company's success doesn't automatically help Chinese tech. It can even highlight the gap.
What it means for you
Asia isn't one trade. Korea, Japan and Taiwan are wired into the US AI build-out. China largely isn't. A broad Asia or emerging-markets ETF holds both, which smooths the swings.
Korea is a concentrated bet. Samsung and SK Hynix make up a huge share of the Kospi. That's why it can fall 18% in a month and jump 3% in a day. If you want Korea exposure, size it accordingly.
Rebounds aren't recoveries. One strong day after a steep fall doesn't confirm a bottom. Watch whether the gains hold through this week's big US tech earnings.
What to watch next
- US tech earnings this week, starting with Microsoft and Alphabet on October 28 (our preview).
- Samsung's full third-quarter results.
- Bank of Japan decision on October 30.
Frequently asked questions
Why did the Kospi rise on October 27, 2026?
Anthropic's IPO filing on October 26 revived enthusiasm for AI chip stocks, and South Korea is home to two of the world's biggest memory chipmakers, Samsung Electronics and SK Hynix. Third-quarter GDP growth of 3.4% year on year also helped after the Kospi had dropped 18.2% in a month.
What is a Kospi sidecar?
A sidecar is a circuit breaker on the Korea Exchange that temporarily suspends program trading, usually for five minutes, when futures prices move sharply. It is triggered by big moves in either direction and is meant to slow automated trading, not stop the market.
Why didn't Chinese stocks join the AI rally?
Natixis economist Alicia Garcia Herrero told Fortune that Hong Kong and mainland markets sit outside the main US AI supply chain. US export controls keep the most advanced chips out of China, and Chinese users already have cheaper domestic AI models such as DeepSeek.
How did Japanese stocks do on October 27, 2026?
The Nikkei 225 rose 1.7% to 63,268.37. Chip-equipment and AI-linked names led: Advantest gained nearly 9%, SoftBank Group about 5% and Tokyo Electron about 3%.
Is the Kospi a good investment after its drop?
The Kospi is heavily concentrated in a few chip stocks, so it swings with the global memory and AI cycle. That can mean big rebounds and big drops. Most investors get Korea through a broad emerging-markets or Asia-Pacific ETF rather than betting on it alone.
Primary sources
Data & disclaimer: This article is for educational purposes only and is not financial or investment advice. Figures reflect data available as of Oct 28, 2026, and conditions change — always confirm current pricing, rates and rules with the provider before you act. Written by Elizabeta Dimoska. See our editorial standards and disclosure.
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