Institutions put 59% of their pre-Chuseok KOSPI buying into Samsung Electronics

Most of the money arrived on three days. Institutions bought 1.23 trillion won on Sept. 16, 1.53 trillion on the 18th and 1.52 trillion on the 21st ^[2], a combined 4.28 trillion won and about 91% of the six-session total ^[1]. The other three sessions, including a net sale of 129.5 billion won on the 22nd ^[2], added roughly 430 billion won between them ^[2]. The 21st was also the day the index closed back above 7,000 for the first time in seven sessions ^[3].

The buying was narrow too. Samsung Electronics alone took 59% of it ^[3], and the three chip names together took about 85%, or 4.02 trillion won ^[4]. Samsung's 14.89% gain was a little more than twice the index's move ^[6][8]. Outside the chip supply chain, the largest net purchase was Doosan at 147 billion won ^[13], about a nineteenth of the Samsung figure ^[10]. Institutions sold NAVER hardest, at 195.5 billion won, and its shares fell 5.49% ^[9].

The flow figures as printed do not balance. Net buying across all investor types has to sum to zero, yet institutional buying covered 4.71 trillion won of the 13.66 trillion won that retail and foreign holders sold ^[5]. That leaves 8.95 trillion won of buying unaccounted for ^[5]. The report does not say who took it, or whether the retail figure covers a longer window than six sessions. If the windows match, institutions absorbed only about a third of the selling ^[6].

"Trading value fell sharply ahead of the holiday, so rather than reading much into this week's swings, investors need to focus on issues after Chuseok," said Kang Jin-hyuk, an analyst at Shinhan Securities ^[11]. The report lists the events due after the break as Micron's earnings, September export data and Samsung Electronics' preliminary results ^[10]. Kang also said: "With semiconductor momentum carrying forward in relay fashion, solid fundamentals could justify the recent compressed gains" ^[12].

If Samsung's preliminary numbers and Micron's results support Yuanta Securities Korea's case, institutions have a reason to keep adding, and the index has a buyer for the shares retail holders are selling ^[8]. The numbers could also be fine while the thin pre-holiday buying unwinds, and the index gives back part of a move built largely on three sessions ^[1]. Or the unassigned 8.95 trillion won turns out to be the steadier buyer, and institutional flow matters less to 7,000 than its headline figure suggests ^[5].

I think the first path is the likeliest. Yuanta lifted its Samsung target by about 19% ^[7] on a supply argument, that high-bandwidth memory production is eating into capacity for conventional DRAM ^[8], and one quarter of results does not settle a claim about 2028. The counter-case is the seller. Retail holders sold a little more than twice what institutions bought ^[9], and that supply of shares will still be there for any post-holiday rally. The view is wrong if Samsung's preliminary result disappoints and institutions then sell for two sessions running, something they did not do in the six before the holiday ^[2].