High-performing investors trading through Mirae Asset Securities (006800.KS) bought the most shares of Samsung Electro-Mechanics (009150.KS), Samsung Electronics (005930.KS) and Cosmax on the 27th. Buying centered on AI server component makers and large-cap memory stocks after Anthropic's move toward an initial public offering eased some concerns about whether AI investment can be monetized.
Samsung Electro-Mechanics was the most heavily bought stock through 11 a.m. among clients ranked in the top 1% by investment returns over the past month, a group the brokerage calls "stock masters," Mirae Asset Securities said. The stock traded at 1,213,500 won at that time, up 8.54% from the previous session.
The buying appears driven by expectations of improving earnings as supplies tighten for multilayer ceramic capacitors (MLCC) and flip-chip ball grid array (FC-BGA) substrates used in AI servers. With the expansion of AI services increasing the number of high-performance components in each server, Samsung Electro-Mechanics has recently expanded long-term supply contracts with global customers and moved to add production capacity. News overnight in the U.S. market that Anthropic is pursuing an IPO also supported the share price by improving sentiment toward AI monetization.
Samsung Electronics ranked second in net buying. The stock traded at 223,250 won, up 4.81%. Anthropic's IPO filing showed surging revenue and a narrowing operating loss, fueling expectations that AI investment is translating into actual service revenue and lifting sentiment toward large-cap chip stocks. The Philadelphia Semiconductor Index rose 2.8% overnight, while Micron and Nvidia gained 3.0% and 2.4%, respectively.
Analysts say the recent decline in chip stocks has been excessive relative to fundamentals. Hana Securities said average daily memory chip exports through the 20th of this month reached $1.58 billion, up 219% from a year earlier, and that third- and fourth-quarter DRAM prices are likely to exceed earlier forecasts. The brokerage also said earnings estimates could be revised upward again after Samsung Electronics and SK hynix (000660.KS) report results.
Cosmax ranked third in net buying, trading at 266,500 won, down 0.56%. GnCenergy (119850.KQ), Simmtech (222800.KQ) and Korea Circuit (007810.KS) also ranked high in net buying. Simmtech and Korea Circuit, both chip substrate makers, surged 11.00% and 12.05%, respectively.
SK hynix, by contrast, was the most heavily sold stock. The shares traded at 1,359,000 won, up 6.59%, at the same time, suggesting the top traders used the rebound as a chance to take profits. SK hynix had ranked first in net buying in the previous session. With third-quarter results due on the 28th and expectations building for higher DRAM prices and shareholder returns, the short-term trading direction reversed in a single day.
Other heavily sold stocks were Doosan Enerbility (034020.KS), Rainbow Robotics (277810.KQ), JYP Entertainment (035900.KQ) and Samsung Electronics preferred shares (005935.KS). In the previous session, the most heavily bought stocks were SK hynix, Samsung Electronics and Doosan (000150.KS), while the most heavily sold were RFMaterials (327260.KQ), Hanwha Solutions (009830.KS) and Simmtech.
Mirae Asset Securities compiles the trades of clients ranked in the top 1% by returns over the past month and publishes the data on its mobile trading system on a real-time, previous-day and five-day basis. The data is provided for information only, does not reflect the brokerage's views and does not guarantee investment outcomes or returns for individual investors. Investors should note that theme stocks can be subject to unusually sharp swings.

