KOSPI falls 0.95%, giving back part of 3.29% rebound

Key takeaways

• The KOSPI was down 0.95% at about 5,681.2 at 01:15 UTC (10:15 Seoul time) on Thursday, October 22, 2026, according to Yahoo Finance data. Over the 30 minutes before that, it fell 1.02%.
• The fall gives back part of the 3.29% rebound on October 21. That session ended at 5,735.66, according to Seoul Economic Daily and Yonhap.
• Yonhap reported that investors "weighed concerns over the profitability of AI infrastructure investments". Bloomingbit pointed to net selling by retail and institutional investors, while foreign investors were net buyers early in the session.
• The Bank of Korea kept its base rate at 3.00% shortly before the move, according to Reuters. No source we reviewed has linked the intraday KOSPI decline to that decision.

South Korea's KOSPI falls 0.95% in Thursday morning trading, to about 5,681.2 at 01:15 UTC on October 22, 2026, giving back part of the previous day's 3.29% rebound. Local reports cited profit-taking and doubts about returns on AI spending.

What happened to the KOSPI this morning?

The index opened lower at 00:00 UTC (09:00 KST). Yonhap, as published by Korea JoongAng Daily, reported that the KOSPI lost 65.55 points, or 1.14%, at the opening bell to 5,670.11.

It recovered some ground in the first minutes of trading. At 00:04 UTC (09:04 KST) it stood at 5,696.74, down 0.68%, according to Bloomingbit. Selling picked up again later. Between about 00:45 and 01:15 UTC the index fell 1.02%, to roughly 5,681.2.

Early in the session, Bloomingbit reported several moves among large caps:

• LG Energy Solution was down 3.16% and Samsung Biologics 1.76%.
• Hyundai Motor was down 1.13%, SK Hynix 0.93% and Samsung Electronics 0.22%.
• Samsung Electro-Mechanics was up 3.94%.
• The tech-heavy Kosdaq was down 0.63% at 787.78.

What we know about the cause

• AI spending doubts. According to Yonhap, investors weighed whether heavy AI infrastructure spending will pay off. In the same report, Yonhap said Meta Platforms had posted solid earnings and increased its bet on AI.
• Profit-taking after the rebound. Bloomingbit reported that at 00:04 UTC retail investors were net sellers of 104.1 billion won and institutions of 70 billion won. Foreign investors were net buyers of 173.1 billion won. Han Ji-young, an analyst at Kiwoom Securities, told the outlet that mixed signals from US after-hours trading could keep the market volatile while it absorbs profit-taking.
• The Bank of Korea held its rate. The central bank left its seven-day repurchase rate at 3.00%, according to Reuters. All 34 analysts in a Reuters poll had expected that outcome. The decision came after quarter-point hikes in July and August. The Korea Herald reported that Governor Shin Hyun-song said the bank would keep tightening "until inflation is firmly on track to reach its 2 percent target."

What we don't know yet

• What caused the 30-minute drop. It came after the rate decision was announced. Because the hold was widely expected, the timing alone does not show a link, and no outlet we reviewed has attributed the move to it.
• Investor flows at 01:15 UTC. We have not been able to confirm whether foreign investors were still net buyers when the index dropped.
• How the session ends. The figures here are intraday. The close may differ, and Governor Shin's news conference was scheduled for 02:10 UTC, according to Reuters.

Background: a volatile October for Korean stocks

The KOSPI has been swinging widely. On October 20 it fell 3.73% to 5,552.74 as foreign and institutional investors sold chip stocks, UPI reported. It rebounded 3.29% the next day.

Seoul Economic Daily linked that rebound to better sentiment after strong results from US AI-related companies, including a better-than-expected revenue outlook from Super Micro and SpaceX's third-quarter results. It also cited strong Korean chip exports. On October 21, Samsung Electronics gained 5.67% and SK Hynix 5.81%. Together, the two companies account for a large share of the index, so their moves heavily shape the KOSPI's direction. For the full October 20 session, see our South Korea daily brief.

On inflation, the Korea Herald reported that consumer prices rose 2.9% in September, down from 3.1% in August but still above the bank's 2% target. Market experts quoted by the paper expect another rate hike at the next meeting on November 26.

Follow-up: see how the KOSPI dropped 3% as chip stocks slid after a US tech selloff, and for the regional picture, our Japan stocks brief for October 22, when the Nikkei sank 2.7% on the same chip selloff.

What it means

The morning's decline shows how closely Korean stocks are tied to the global debate about AI spending. Whenever investors reassess whether large AI infrastructure budgets will deliver returns, chip heavyweights move, and the index moves with them. A near-1% fall after a 3.29% gain falls within the recent range of daily swings. Sources attribute the selling to profit-taking and AI concerns, not to a new shock.

The Bank of Korea's hold removes one near-term event, but its tightening bias remains, according to the governor's comments. That leaves US tech earnings, chip export data and foreign investor flows as the main drivers to watch in the coming sessions.

Sources

• Korea JoongAng Daily (Yonhap): KOSPI opens lower as AI investment profitability concerns persist
• Bloomingbit: Kospi falls back below 5,700 after one-day rebound as chip stocks weaken
• Seoul Economic Daily: Samsung Electronics, SK hynix jump over 5% as KOSPI reclaims 5,700
• Reuters via Yahoo Finance: Bank of Korea holds rates as expected after back-to-back hikes
• The Korea Herald: BOK holds key rate steady at 3% after 2 consecutive rate hikes
• UPI: South Korea's Kospi plunges 3.73%
• Yahoo Finance: KOSPI Composite Index (^KS11) quote

This article is for information only and is not investment advice.