The stocks most heavily bought by high-performing investors trading through Mirae Asset Securities (006800.KS) on the morning of the 21st were Samsung Electro-Mechanics (009150.KS), SK hynix (000660.KS) and Samsung Electronics (005930.KS), in that order. They sold heavily in Samsung Electronics preferred shares, LG Defense & Aerospace and SK.
According to Mirae Asset Securities, Samsung Electro-Mechanics was the most-bought stock through 11 a.m. that day among "top stock traders" — the brokerage's clients ranking in the top 1% by investment return over the past month.
Samsung Electro-Mechanics was trading at 1.202 million won at that time, up 4.07% from the previous session. The stock moved from the top net sell position among the top traders the previous day to the top net buy spot that morning. Analysts are focusing on improving earnings driven by a supply shortage and rising prices for semiconductor package substrates. Mirae Asset Securities raised its operating profit estimates for Samsung Electro-Mechanics by 15% for the fourth quarter and 6% for next year the previous day, while maintaining its target price of 2.8 million won. "The supply shortage that began in MLCCs and FC-BGAs for AI servers is spreading to general-purpose package substrates," said Park Jun-seo, an analyst at Mirae Asset Securities. "This is a period in which earnings improvements are appearing across all business divisions simultaneously."
SK hynix ranked second in net buying. Its shares were at 1.321 million won, up 8.01% from the prior session. While concerns about the profitability of AI investment persist, strong results from a U.S. AI server maker appear to be lifting sentiment toward semiconductor stocks. Overnight, Super Micro Computer offered preliminary revenue of about 24.8 trillion to 26.2 trillion won for July through September, more than 3.5 times the figure a year earlier. The range far exceeded its earlier guidance and the market consensus of 20.4 trillion won, sending the stock up about 13% in after-hours trading. Expectations ahead of earnings announcements from U.S. big tech firms including Meta are also seen as a factor.
Samsung Electronics took third place in net buying. It was trading at 226,750 won, up 7.21% from the previous session. The stock stayed near the top of the list after ranking first in net buying the previous day. KB Securities estimated in a report the previous day that Samsung Electronics has secured about 80% of its planned memory output for next year through long-term supply contracts. It projected operating profit of 367 trillion won this year and 555 trillion won next year. "There is limited scope for the direction of next year's profit growth to be undermined, given the volumes secured through long-term supply contracts and rising memory prices," said Kim Dong-won, head of research at KB Securities.
Samsung Electronics preferred shares, meanwhile, topped the net selling list. They were trading at 174,200 won, up 5.00% from the prior session. The top traders bought Samsung Electronics common shares while net selling the preferred stock. LG Defense & Aerospace, second on the net selling list, was at 467,000 won, down 14.78%, while SK, in third place, was at 478,000 won, up 11.68%.
In the previous session, the top traders' most-bought stocks were Samsung Electronics, Doosan Enerbility (034020.KS) and STI, in that order. The most-sold were Samsung Electro-Mechanics, SK hynix and Samsung Electronics preferred shares.
Mirae Asset Securities compiles the trades of investors ranking in the top 1% by return over the past month among its own clients and discloses them on its mobile trading system on a real-time, previous-day and five-day basis. The data is simply informational and unrelated to the brokerage's own views, and does not guarantee investments or returns suited to any individual investor. Investors should also note that theme stocks carry the risk of abnormal price swings.

