KOSPI plunges 5%, triggers sell-side sidecar as Samsung and SK Hynix tumble; Nikkei and Taiwan fall nearly 3%
South Korea's KOSPI fell about 5% on October 30, its first sidecar halt in 11 sessions, as Alphabet's AI spending shock and the Binance hack hit Asian tech.
At a glance
- South Korea's KOSPI dropped close to 5% on Friday, October 30, 2026, trading around 5,640 in the morning and closing about 5% lower.
- The Korea Exchange paused program selling for five minutes at 10:04 a.m. Seoul time, the first sell-side 'sidecar' in 11 trading sessions.
- SK Hynix fell almost 9% to 1.39 million won and Samsung Electronics lost 5–6%; foreign investors sold more than 500 billion won of shares in the morning.
- Japan's Nikkei 225 and Taiwan's TAIEX each fell nearly 3%, while Hong Kong's Hang Seng and Australia's ASX 200 edged higher.
- The trigger was a 12.6% fall in Alphabet after it said its AI spending would more than double, wiping about $500 billion off its value, plus a suspected multi-billion-dollar hack at Binance.
South Korea's stock market fell almost 5% on Friday, October 30, 2026, the steepest drop in Asia, as investors dumped chipmakers after Alphabet's huge jump in AI spending revived fears that the artificial-intelligence boom is costing more than it earns. The slide was fast enough to trigger an automatic five-minute pause on program selling in Seoul.
The KOSPI was trading at about 5,642 in the late morning, down roughly 295 points, or 4.98%, from Thursday's close near 5,938. Only two days earlier, on Wednesday, the index had climbed back above 6,000 after Samsung and SK Hynix jumped on strong memory-chip results. That rally has now been erased.
Ten past ten: the sidecar fires
At 10:04 a.m. Seoul time the Korea Exchange suspended program sell orders on KOSPI stocks for five minutes. This "sidecar" is triggered when KOSPI 200 futures move 5% from the previous close and stay there for a minute. It was the first sell-side sidecar in 11 trading days, a sign of how quickly sentiment turned in October.
The smaller, tech-heavy KOSDAQ also dropped more than 4%.
Chip giants take the hardest hit
Samsung Electronics and SK Hynix together make up a large part of the KOSPI's value, so their fall dragged the whole index down.
| Market / stock | Move on October 30 (morning) | Level |
|---|---|---|
| KOSPI (South Korea) | about −5% | ~5,640 |
| KOSDAQ (South Korea) | about −4.3% | — |
| SK Hynix | −8.9% | 1.39 million won |
| Samsung Electronics | −5% to −6% | — |
| Nikkei 225 (Japan) | about −2.8% | — |
| TAIEX (Taiwan) | −2.8% | ~45,070 |
| Hang Seng (Hong Kong) | small gain | — |
| S&P/ASX 200 (Australia) | small gain | — |
Morning trading figures; closing levels may differ.
Foreign investors were the biggest sellers. They had sold more than 500 billion won (about $370–415 million) of KOSPI shares by mid-morning, and local institutions also sold. By the close the index had lost about 5% on the day, with the KOSDAQ down about 4.3%, leaving the KOSPI more than 17% lower for October after a record run earlier in 2026.
In Taiwan, TSMC fell sharply as the TAIEX lost more than 1,200 points at one point. In Japan, chip-equipment makers and AI-linked stocks led the Nikkei lower, on the same morning that the Bank of Japan held its rate at 1.25%.
Why Alphabet's numbers spooked Seoul
Alphabet's shares dropped 12.6% in New York on Thursday, their worst day since 2004, after the Google owner said its capital spending on data centres and AI chips would more than double. The fall wiped about $500 billion off its market value. Investors worried that the giant AI budgets of US tech companies are pushing their cash flow negative without clear returns.
That matters directly for Korea. Samsung and SK Hynix sell the high-bandwidth memory (HBM) chips that go into AI servers. When US tech firms spend more, they buy more Korean chips — but if investors start to doubt that the spending can last, chip stocks are the first to be sold. Weak results from Amazon and Intel after the US close on Thursday added to the gloom.
A second shock came from crypto. A suspected hack at Binance, the world's largest cryptocurrency exchange, in which several billion dollars of assets are believed to have been drained from its hot wallets, pushed bitcoin lower. Korean won-based crypto exchanges issued withdrawal warnings to customers, hitting retail investors who are active in both crypto and stocks.
What it means for investors in Pakistan and South Asia
Pakistani and Indian markets are not directly tied to Korean chipmakers, but a global tech sell-off usually lifts the US dollar and pushes foreign funds out of emerging markets in general. Investors in the Pakistan Stock Exchange and India's Nifty IT stocks will watch whether the selling spreads into Europe and Wall Street later on Friday. For people holding crypto through local apps, the Binance situation is a reminder to check whether withdrawals are working before moving funds.
What to watch next
Attention now turns to Wall Street's Friday session and to Apple, which reports its quarterly results on November 2, the last of the big US tech companies to do so this season. Korean market officials may also face questions about whether further stabilisation steps are needed if the selling continues into November.
