The Korean KOSPI index demonstrated a powerful rebound, adding 4.53% to Monday's closing level and reaching 5,717.30 points on Tuesday morning. Such a rapid rise forced the Korea Exchange to activate the buy-side sidecar mechanism for five minutes — this is already the second such pause in six days.
The previous trading halt occurred on October 21, but the momentum could not be sustained then: the entire KOSPI gain was fully erased within two days. Now the fate of the new rebound depends directly on the financial results of SK Hynix and Samsung Electronics, which will be published this week.
Memory makers pulled the market up, oil supported the rally
The Korea Exchange activated the buy-side sidecar at 10:13 local time. Investor sentiment improved markedly after the overnight rally in artificial intelligence sector stocks on the US market.
Chipmakers set the tone for US trading on Monday. The Philadelphia Semiconductor Index rose 2.82%, the Nasdaq Composite added 0.82% and reached 26,169.38, while the S&P 500 climbed 0.70% to 7,676.77.
Brent declined after talks between officials from Saudi Arabia, Pakistan, and Turkey in Tehran. On Tuesday morning, a barrel cost $114.64 — 1.01% below the previous day's level. At the same time, Brent is still 17.28% higher than a month ago.
In Seoul, the rally was led by the leading memory manufacturers. By 10:35, SK Hynix shares had risen 7.14% to 1.366 million won. Samsung stock gained 4.93% and reached 223,500 won.
The South Korean market posted the best result among Asian exchanges on Tuesday. Japan's Nikkei 225 rose 1.96% to 63,407.69, and Taiwan's TAIEX added 0.47% to reach 46,260.03.
On October 15, the dynamics were the opposite: KOSPI fell 7.57% after the release of US inflation statistics. At that time, the Nikkei declined 4.90% and the TAIEX fell 3.41%. Due to the high share of memory manufacturers in the index, KOSPI's dynamics traditionally amplify market sentiment around AI in both directions.
Two reports hold back a new rally
The rebound began after the sell-off in chipmaker stocks. KOSPI ended Monday roughly 40% below its June peak. Foreign investors sold a net 695.5 billion won worth of assets that day.
Goldman Sachs on Sunday lowered its KOSPI target from 12,000 to 9,000. According to the bank's calculations, current chipmaker valuations imply a 65% decline in sector earnings by 2027, although the bank itself considers this forecast overly pessimistic.
SK Hynix will present its third-quarter financial results on October 28, and Samsung will report on October 29. Memory manufacturers account for almost half of the entire index.
Retail investors remain at risk of being hit if negative reports are released. A clear forecast for memory prices in 2027 would strengthen Goldman's position. If expectations remain weak, the market will continue to price in a 65% earnings decline — and then Tuesday's rally could quickly fade, just as it did on October 21.
Cryptalist analysis: KOSPI volatility has reached extreme levels: two trading halts in six days signal the fragility of a market structure where almost half of the index depends on two issuers. Institutional investors will evaluate SK Hynix and Samsung's reports not so much on quarterly figures as on memory price forecasts for 2027 — this is precisely the factor that will determine whether the current rebound becomes a sustainable reversal or another short-term pause before the correction continues.