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KOSPI Opens Sharply Lower, KOSDAQ Surges Despite SOX Slump — Korea Market Morning Session, Aug 11, 2026

The KOSPI gapped down at the open on Tuesday, August 11 (2026), with the index touching a session low of 6,213.78 at 09:07 before recovering to the 6,240–6,278 range through mid-morning, as the Philadelphia Semiconductor Index had fallen 2.94% in the prior U.S. session.The KOSDAQ, by contrast, opene

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A daily data newsletter on the Korean stock market — silmari, ‘a clue: the loose end that unravels the knot’
② Early Session 10:002026.08.11 Tue · No. 9Sentiment gauge: Neutral — composite score 0.886; vol20 component at the 95th percentile (expanding-window, 2026 regime), leverage ETF share at the 86th percentile; three inputs including short-surge and credit data not yet available for today.
② Morning Session · published 10:00 KST · session in progress
01 · VerdictRegular session confirmed 15:30 KST

10:00verdict at this hour

KOSPI Opens Sharply Lower, KOSDAQ Surges Despite Philadelphia Semiconductor Index (SOX)A U.S. equity index tracking 30 major semiconductor companies, widely used as a real-time barometer of global chip-sector sentiment.Because Korean chipmakers Samsung Electronics and SK hynix are among the world’s largest semiconductor producers, a sharp SOX move overnight often correlates with their opening-bell direction on the KRX. Slump

The KOSPI gapped down at the open on Tuesday, August 11 (2026), with the index touching a session low of 6,213.78 at 09:07 before recovering to the 6,2406,278 range through mid-morning, as the Philadelphia Semiconductor Index had fallen 2.94% in the prior U.S. session.The KOSDAQ, by contrast, opened near 847 and climbed steadily through the first hour, reaching 875.16 at 09:51 before easing back toward 869 by 10:10 — a divergence that confounded the morning call, which had forecast a muted or slightly lower open for the secondary market.

Key points
01KOSPI opened at 6,229.27, hit a low of 6,213.78 at 09:07, then bounced to 6,278-area highs by 09:55 before drifting back toward 6,2406,252 as of 10:10 — a high-low range of 61.96 points (≈1.0%) within the first hour.
02KOSDAQ surged against the grain: the index advanced from its open of 847.41 to an intraday high of 875.16 at 09:51, running 3.76% from session low to high — the morning call (“flat to slightly lower”) missed badly, with the index closing at +2.05%.
03SK hynix led KOSPI turnover at ₩1.17tn, but traded −2.18%; Samsung Electro-Mechanics fell −4.63% on ₩167.8bn. Jusung Engineering topped KOSDAQ turnover at ₩149.5bn, rising +12.85%.
04Preliminary flow data (as of 10:11 KST) show foreigners net selling ₩235bn on KOSPI and ₩202.7bn on KOSDAQ; retail investors offset with net buying of ₩280.3bn and ₩166.8bn respectively — figures are provisional and subject to end-of-day revision.
05First scorecard on this morning’s calls (intraday, provisional) — P3 SK hynix: we called a decline of -2% to -4%, and it stands at -2.89% versus the prior close — a hit (✓). P1 KOSPI: the direction (down) was right, but at -0.80% the move falls short of our -1.5% to -2.5% range — partial credit (△). P2 KOSDAQ: we called flat-to-slightly-lower; it is up +2.05% instead — a miss (✗).
P4 and P5 await their verdicts; final scoring runs in the Final edition (20:00 KST)
02 · SnapshotSnapshot — minute-bar readings

10:00Snapshot

A window that records the market at that hour, like a photograph

Foreigners Net Sell ₩235bn on KOSPI and ₩202.7bn on KOSDAQ in Early Trade; Retail Offsets Both Markets

KOSPI snapshotOpen6229.27· High6278.34(09:55) · Low6213.78(09:07) · Last6254.78
KOSDAQ snapshotOpen847.41· High875.16(09:51) · Low840.45(09:07) · Last865.69
03 · Top 10 checkpointsMinute-bar readings · low and high times included

Top by trading value10— snapshot

A window on how the top trading-value names have moved up to this hour

SK hynix Tops KOSPI Turnover at ₩1.17tn Despite −2.18% Drop; Jusung Engineering Leads KOSDAQ at ₩149.5bn

Among the top ten by turnover on the KOSPI, SK hynix registered the widest intraday range — opening at 1,405,000 won, reaching a high of 1,410,000 at 09:04, then sliding to a low of 1,373,000 at 10:09 — while Samsung Electronics moved in a narrower band between 227,500 (low, 09:18) and 232,500 (high, 09:04), settling near 231,000.Hanwha Solutions was the most volatile of the KOSPI top ten in proportional terms, swinging from a low of 32,900 at 09:03 to a high of 38,250 at 09:18 before settling at 36,350, generating ₩167.3bn in turnover; Kumho Engineering & Construction extended gains from its 09:00 low of 8,940 all the way to 11,490 by 10:01 on ₩116.5bn.

Top 10 by trading value — prior close · open · gap · high (time) · last · change · low (time)
StockPrior closeOpenGapHigh (time)High (time)Low (time)
SK hynix1,419,9551,405,000−1.05%1,410,000 (09:04)1,389,000−2.18%
Samsung Electronics230,011229,500−0.22%232,500 (09:04)231,000+0.43%
Daewon Cable14,95015,050+0.67%16,160 (09:12)15,330+2.54%
Samsung Electro-Mechanics1,273,9861,238,000−2.82%1,241,000 (09:00)1,215,000−4.63%
Hanwha Solutions35,25034,200−2.98%38,250 (09:18)36,350+3.12%
Kumho E&C8,8409,030+2.15%11,490 (10:01)11,180+26.47%
SK eternix51,30052,400+2.14%54,800 (09:10)52,500+2.34%
SK Square949,048929,000−2.11%935,000 (09:04)922,000−2.85%
Samsung Electronics (Pref.)171,996170,000−1.16%173,300 (09:04)171,600−0.23%
GS E&C34,90034,200−2.01%36,200 (10:08)35,800+2.58%

On the KOSDAQ, Jusung Engineering’s session low came at the open (139,300 at 09:00) and its high of 163,800 arrived by 09:12, with the stock holding near that level through 10:10 — indicating the opening gap held rather than faded.Samsung Electro-Mechanics stood out on the KOSPI as a stock whose high (1,241,000) was printed at the very first minute of trade (09:00) and whose low (1,191,000) came at 10:09, reflecting steady intraday selling pressure that deepened as the morning progressed.

04 · Up · DownReason labels: [News] confirmed · [Pattern] inferred

Gainers5· Decliners5— snapshot

A window on the biggest gainers and decliners, and the reasons behind them

Defense & Power Names Slide While Construction, Energy Lead Gainers; KOSDAQ Semiconductor Equipment Surges

On the KOSPI, the sharpest declines were concentrated in defense & aerospace (Korea Aerospace Industries −6.29%, Hyosung Heavy Industries −4.09%, LS ELECTRIC −3.12%) and consumer names (CJ CheilJedang −7.15%), while construction and energy credits advanced — Hyundai Construction +4.07%, S-Oil +5.37%, Hanwha Solutions +3.12%.On the KOSDAQ, semiconductor equipment names dominated the gainers: Jusung Engineering +12.85%, Wonik IPS +9.25%, and SPG +9.22% — running counter to the semiconductor sector’s weak tone on the KOSPI — while Daehang Fiber Optics fell −5.34% on heavy volume (₩100.9bn).

Gainers —5:00as measured at this hour
Losers —5:00as measured at this hour
Historical contextSelection: turnover of ₩10bn or more · machine ranking by percentage change.
Source: Korea Exchange ·Nextrade (NXT)South Korea’s alternative trading system (ATS), launched in 2025, which operates pre-market and after-market sessions outside the KRX’s standard 09:00–15:30 hours.NXT pre-market activity can reveal the direction of institutional and retail order flow before the KRX main session opens, providing an early read on sentiment.· Actual · Regular session 15:30 close · Compiled by Editorial Team.
This edition organises and explains publicly available market data. It is not investment advice. Predictions and their scores are preserved without revision — the judgement is yours.