KOSPI falls nearly 8% as AI trade reverses in 2026

A fast rally meets a sudden reversal

South Korea’s equity market faced a sharp reversal after an AI-driven run that had pushed the country into the spotlight as one of the world’s hottest equity markets. On Tuesday, the Korean benchmark dropped steeply as investors moved quickly to lock in profits. The selloff was concentrated in heavyweight technology names that had benefited most from the AI optimism. The move also tested market safeguards, with the exchange stepping in to cool activity. The decline followed growing caution around elevated valuations in AI-linked stocks, which had already started to show up a day earlier. The episode underlined how quickly sentiment can flip when positioning is crowded and expectations are high.

What happened on Tuesday in early trade

As of 9:50 am IST, the Korean benchmark was down more than 7% at 7,478.61, falling 572.72 points. The drop was described as a sharp reversal for an index that had inched to record highs this year. The benchmark had crossed the 9,000 milestone just days earlier, before being pulled lower by the same momentum trade that had driven it up. Investors’ rush to book profits turned what began as a correction into a broad selloff in large-cap technology. Market participants also pointed to a broader shift from optimism to caution after months of gains linked to artificial intelligence.

KRX steps in with a “sidecar” and a program halt

The Korea Exchange (KRX) activated a sell-side sidecar, a mechanism used to calm markets during abrupt moves. Programme trading on the benchmark KOSPI was suspended for five minutes at around 10:23 am, according to Yonhap News Agency, after the index plunged sharply. The temporary pause highlighted the intensity of the selling pressure and the role of systematic trading during fast drawdowns. Such measures are designed to slow down program-driven orders when price moves become disorderly. While the halt was short, it signaled that the selloff had crossed thresholds that warrant immediate market controls.

Chipmakers led the fall as AI positioning unwound

Technology heavyweights were at the center of the decline. In the morning move cited, Samsung Electronics fell 7.4%, while SK Hynix declined 6.4% ahead of its planned US listing later in the week. Other reports in the same set of updates also described even deeper losses in later sessions, with SK Hynix losing nearly 15% and Samsung Electronics falling 9.1% as the KOSPI closed down nearly 8%. The concentration of losses in the largest chipmakers mattered because these companies have been key drivers of the market’s strong performance. The price action also reflected a clear shift away from AI-linked exposure as investors questioned whether the rally had run too far, too fast.

Why strong Samsung earnings still coincided with selling

The selloff accelerated after Samsung Electronics unveiled stronger-than-expected quarterly earnings, which paradoxically became a trigger for profit-taking. Despite the upbeat earnings signal, investors opted to cash in after months of AI-led gains, pulling the broader technology sector lower. The article also notes that, excluding certain provisions, Samsung’s quarterly operating profit was estimated at around 100 trillion won. Even with that earnings strength, the market reaction suggested investors were focused less on current results and more on the sustainability of expectations priced into semiconductor stocks. In fast rallies, “good news” can become a selling opportunity when many investors are already sitting on large gains.

Foreign investors were the biggest sellers

Foreign investors were reported as the biggest sellers during the drop, offloading a net 1.74 trillion won worth of shares. That net selling pressure added to the momentum of the decline, particularly in liquid index heavyweights. When foreign flows turn decisively negative, it can amplify downside moves because large positions are often concentrated in benchmark constituents. The combination of profit-taking and foreign selling is consistent with a market that had been priced for continued AI-driven upside.

Valuation anxiety and “overcapacity” fears enter the narrative

Concerns over AI valuations were already visible a day earlier, when South Korean equities reportedly gave up gains as investors grew cautious about elevated pricing in AI-linked shares. Reuters had noted that after climbing more than 2% early on Monday, the KOSPI reversed to fall more than 2% as investors reassessed the rapid rally. Later reports broadened the concern beyond Korea, citing fears that massive spending on AI infrastructure may have gone too far. One trigger cited was a report that Meta Platforms plans to commercialise excess AI computing capacity by selling access to AI infrastructure and models, which investors interpreted as a possible signal of overbuild in computing capacity.

Spillovers across Asia, while Indian IT moved differently

The selloff narrative spread across Asian chip-heavy markets, with South Korea and Taiwan described as coming under heavy selling pressure as investors questioned whether the AI investment boom had run too far. In contrast, Indian technology stocks were reported to rebound, with the Nifty IT index rising as much as 4.6% to 26,946.35 after falling 6.5% over the previous four sessions to its lowest level in more than five years. The contrast reflected differing market exposures, with Korean and Taiwanese benchmarks more tightly linked to hardware and semiconductors, while Indian IT is more tied to software spending trends.

Key data points from the selloff

Why this matters for investors tracking the AI trade

The week’s volatility shows how quickly AI-linked trades can shift from optimism to anxiety when valuations are questioned. For South Korea, the heavy index weight of large chipmakers makes the market especially sensitive to semiconductor sentiment and global AI capex expectations. The activation of market-curbing tools like a sidecar and program trading halts also illustrates how rapidly liquidity conditions can change during large, correlated selloffs. Reports also pointed to additional uncertainty drivers, including potential competition risks, such as Apple considering memory sourcing from two Chinese semiconductor manufacturers.

What to watch next

Investors are likely to watch follow-through flows after the foreign selling spike and whether tech heavyweights stabilise after the sharp repricing. Attention will also remain on AI infrastructure spending signals, including any indications of excess capacity and how big buyers of compute and memory manage capex. In South Korea, the market’s next moves may hinge on whether earnings strength can reassert itself after profit-taking, and whether exchange safeguards are needed again if volatility persists.