On the 6th, the day after technology stocks fell as the "AI bubble" debate rekindled on Wall Street, an unprecedented event occurred when Samsung Electronics' share price plunged near the lower limit in the premarket before the regular session opened in Korea. The stock, which was 170,000 won the previous day, slid to 111,600 won, triggering the volatility interruption (VI) mechanism. Even if it was a temporary phenomenon in the premarket, where trading volume is light, a 30% drop in Samsung Electronics, whose market capitalization nears 1,000 trillion won, was highly unusual.
Since the global AI boom, exploding interest in Samsung Electronics and SK hynix has made near-10% daily swings in the No. 1 and No. 2 market-cap stocks frequent.
It is not just about large semiconductor stocks. After Hyundai Motor unveiled Boston Dynamics' Humanoid Robot "Atlas" at the world's largest IT exhibition, CES 2026, Hyundai Motor Group shares surged across the board.
Also, when Tesla CEO Elon Musk recently mentioned a plan to use solar power in SpaceX's space business, solar-related stocks such as Hanwha Solutions spiked. A similar pattern appeared right after the meeting between Minister of Foreign Affairs Cho Hyun and U.S. Secretary of State and National Security Adviser Marco Rubio earlier this month. As the two countries discussed cooperation in nuclear power generation, the outlook of "tomorrow is the turn for nuclear power stocks" spread across online securities communities, and nuclear-related stocks such as Korea Electric Power Corporation and Hyundai Engineering & Construction indeed jumped right after the open.
Some in the market say the Korean stock market has degenerated into a "meme stock" regime. This is because large-cap stocks on the main board, with market caps ranging from trillions to tens of trillions of won, are repeatedly soaring and plunging by double digits in a day on word-of-mouth in online communities.
A senior official at an asset management firm said, "It is normal in a 'rotation market' for funds to flow into other sectors after leading sectors rise and lift the market, but it is hard to see the recent large-cap whipsaws on short news as ordinary rotation," adding, "Previously, small-cap stocks became meme stocks, but now large caps have become meme stocks."
Experts point to a shift in the investor base driving Korea's market as the backdrop for this phenomenon. Instead of foreigners or pension funds with long-term horizons, individual money targeting short-term gains is leading the market, they say. The old formula—indexes slumping when foreigners sold—has broken, and individual money now holds the pricing power in large caps.
According to the Korea Exchange (KRX), in the main board from Jan. 2 to Feb. 6, individual investors net bought more than 9 trillion won. In the financial investment category, which includes exchange-traded funds (ETFs) that are a primary vehicle for individual money, net buying came to nearly 4 trillion won. By contrast, foreign investors net sold more than 10 trillion won over the same period. This suggests that individuals are steering the direction of the overall market (the index) beyond individual stocks.
Idle funds showing the heat of individual investing are also at record highs. According to the Korea Financial Investment Association, investor deposits this month are about 111 trillion won, an all-time high. The number of active domestic stock transaction accounts has also surpassed 100 million. As policy focus shifted to revitalizing the stock market after the launch of the new administration last year and domestic stocks surged, household funds have been flowing into the market en masse.
In particular, in recent days individual money has been "clustering" in certain stocks. In the past, individual investors lacked information and had widely differing views on stocks, making it structurally difficult for individual money to move collectively like institutional investors.
But as communities and social media for sharing investment information have expanded, many investors now quickly obtain similar information and, in some cases, collectively react to one-sided information. This is seen as the reason why herding-driven surges and slumps often occur in stocks that attract the attention of many investors.
In a report released in January, JP Morgan said, "The increase in social media use and the digital transition have facilitated information flows that influence investors' decision-making," adding, "Its impact is being amplified by the recent meme stock craze."
According to research by the Korea Capital Market Institute, in the domestic stock market, young investors and new investors show strong tendencies toward clustered trading, and the more a stock draws market attention, the stronger the clustered trading tendency among individual investors becomes.
The problem is that such one-sided flows swing prices more than corporate value does, widening market volatility. In particular, if funds exit based on group psychology after a rapid run-up, regardless of fundamentals, even quality large caps face a high risk of sharp drops.
An official at a major securities firm pointed out, "Online communities intended to resolve information asymmetry can instead amplify collective misjudgment."
☞ Meme stock: A portmanteau of "meme," meaning content that goes viral online, and stock. Refers to shares whose prices surge and plunge on word-of-mouth among individual investors in online spaces such as social media.