Дослідження з перевіркою джерел: Bitget

What happened in Seoul, hour by hour

The Korea JoongAng Daily reported that the KOSPI opened 335.80 points, or 5.59%, lower at 5,673.01 and kept sliding. A sell-side sidecar, which pauses programme sell orders for five minutes once KOSPI 200 futures fall at least 5% for a full minute, triggered on the main board at 09:07 Seoul time (08:07 SGT), and a second one hit the KOSDAQ at 09:12 after KOSDAQ 150 futures dropped 6.25%. It was the first day both markets tripped sell-side sidecars together since 29 July.

By 10:30 Seoul time (09:30 SGT) the index stood at 5,539.51, down 7.77%. Aju Press put the intraday low at 5,534.24, with 840 decliners against 64 gainers on the main board, and at 11:20 Seoul time the KOSPI had steadied slightly at 5,605.10, still down 6.75%. A close at those levels would be the index's first seven-session losing streak since September 2024, and it leaves the benchmark back where it traded in April, far below the record above 9,000 it set in June.

The two stocks that matter most for the index did the damage. Samsung Electronics fell 9.05% to 211,000 won and SK hynix fell 10.71% to 1,267,000 won in the first ninety minutes, according to the JoongAng Daily; the Associated Press had them at −8.2% and −10.8% around the same time. The fear gauge told the same story: Aju Press reported the VKOSPI at 53.84 at 10:49, up 19.88% on the day, after an intraday high of 55.64, its highest since 26 August.

Why it happened: three pressures at once

The sell-off has no single trigger. Korean brokers and the wire services cited the same three forces.

US inflation and rates. The Associated Press reported that US consumer prices rose 3.7% year on year in September, up from 3.4% in August and above what economists expected. Wall Street sold technology on Wednesday: the Nasdaq composite fell 1.9%, the S&P 500 lost 1.1%, Nvidia dropped 3.2%, Broadcom 3.1% and AMD 5.7%. The JoongAng Daily added that the 10-year US Treasury yield touched 5.329% at one point. "Right now, interest rates are a clear burden," Kim Hak-kyun, head of research at Shinyoung Securities, told the paper. Our own piece on why Bitcoin fell after the CPI print covers the crypto side of the same release.

Doubts about AI spending. Park Yeon-ju, head of research at Mirae Asset Securities, said concerns over whether massive AI investment can generate sufficient returns had the biggest impact. The JoongAng Daily pointed to CoreWeave, whose shares fell 15.5% on Wednesday over its debt load while its corporate bond yields jumped to about 15%, and to Anthropic's third-quarter revenue growth slowing from the previous quarter. Memory chips are the most cyclical part of the AI build-out, which is why Korea's two memory giants take the hardest hits when that trade wobbles. The AP noted that SoftBank Group fell 9.1% and Tokyo Electron 6.3% in Tokyo, where the Nikkei 225 lost 3.9% to 65,119.51.

Chinese memory supply. Worries about expanded supply from China's ChangXin Memory Technologies (CXMT) have hung over Samsung and SK hynix for days and were cited again on Thursday.

Behind all three sits one mechanical fact: foreigners were net sellers of 1.92 trillion won (about $1.4 billion) of main-board shares by 10:30, their eighth consecutive day of selling, and Aju Press had the figure at 2.45 trillion won by late morning. Retail investors bought 628.8 billion won and institutions 1.11 trillion won, which was not enough. Lee Min-hwan, a finance professor at Inha University, told the JoongAng Daily that psychological factors were playing a large role in the particularly sharp fall.

How it hit crypto venues

Korean stocks trade 24/7 on crypto exchanges through perpetual futures, and those contracts had already priced most of the Seoul open before Seoul opened. The Korea Times reported in June that Binance listed KORUUSDT on 22 June, a perpetual tied to KORU, a triple-leveraged KOSPI ETF listed on the New York Stock Exchange, with leverage up to 20x, after listing SAMSUNGUSDT, SKHYNIXUSDT and HYUNDAIUSDT on 2 June. Because KORU itself moves three times the index, a 7% to 8% KOSPI day translates into a 20%-plus move in the perp.

That is exactly what showed up. As read from Binance Futures at 02:50 UTC (10:50 SGT) on 15 October:

KORU was the ninth most-traded USDT perpetual on Binance in that window, ahead of XRP. The Bitget KORUUSDT perp told the same story at 03:05 UTC: last 10.617, down 28.07% on 185.7M USDT of volume, with SKHYNIXUSDT at −14.71%, SAMSUNGUSDT at −12.25% and the EWYUSDT perp on the unleveraged iShares Korea ETF at −9.78%. Bitget's hourly candles show the decisive leg came between 23:00 UTC on 14 October and 01:00 UTC on 15 October (07:00 to 09:00 SGT): KORU opened the 00:00 UTC hour at 11.957, printed a 10.927 low on 20.6M USDT, then slid to 10.561 in the next hour, all before the first Seoul sidecar.

The crowd was on the wrong side. Binance's long/short account ratio for KORUUSDT read 5.9 to 7.1 through the 00:00 to 02:00 UTC hours, meaning roughly 86% to 88% of accounts holding a position were long, and open interest stood near 10.7 million contracts. Funding showed the squeeze: Binance KORUUSDT funding was +0.096% and Bitget's +0.1045% per period, with SKHYNIXUSDT at +0.269% on Binance. Longs were paying heavily to stay in a position that had already lost a quarter of its value.

Our funding-rate board ranks KORU and the chip perps against BTC and ETH in real time, and the liquidations page tracks forced closes across Binance and OKX; across all symbols those two venues logged 748 million dollars of liquidations in the 24 hours to 02:46 UTC, 549 million of them longs.

Crypto itself was softer rather than broken: BTC was down 2.6% at 81,358 and ETH down 5.35% at 2,375 on Binance at the same read, extending the post-CPI slide we covered in why chip stocks and SOXL perps were already falling.

What this means for you

If you hold a Korea or chip-stock perp, the risk is not the headline percentage; it is leverage stacked on leverage. KORU is a 3x daily product, and a 20x perp on top of it means a 1% KOSPI move swings the position by roughly 60%. Positive funding of about 0.1% every period adds a cost that compounds while you wait for a bounce. Reduce size or switch to the unleveraged EWY perp if you want Korea exposure without the gearing, and set stops with the Seoul open (09:00 KST, 08:00 SGT) in mind, because that is when the daily gap gets priced.

If you trade the rebound, know what has to change: the eight-day foreign selling streak, the US rate outlook, and the AI-capex narrative. None of those will be settled by a single candle. Our tokenized stocks hub explains how stock perps, tokenized shares and spot stock trading differ, which matters when you choose how to express a Korea view.

1% per period, the fee you keep matters.

Quick answers

Why is KOSPI down today? Foreign investors sold Korean chip stocks for an eighth straight day after US September CPI came in at 3.7%, raising Fed-hike odds, while doubts about AI investment returns and Chinese memory supply hit Samsung and SK hynix.

How much did KOSPI fall? About 7.8% at the 10:30 Seoul low (5,539.51) and 6.75% at 11:20 (5,605.10), with an intraday low of 5,534.24; the index opened 5.59% lower.

What is KORU and why did the KORU perp fall 28%? KORU is a triple-leveraged Korea ETF on the NYSE; the Binance and Bitget KORUUSDT perps track it, so a 7% to 8% KOSPI drop became a 28% move.

Was a trading halt triggered? Yes, sell-side sidecars fired on the KOSPI at 09:07 and on the KOSDAQ at 09:12 Seoul time, pausing programme sell orders for five minutes each.

Did crypto fall with Korean stocks? Modestly: BTC was down 2.6% and ETH 5.35% at the 02:50 UTC read, with 748 million dollars liquidated across Binance and OKX in 24 hours.

Where can I see live funding on the Korea perps? On the funding-rate board; the Bitget perps are listed on our Bitget profile.