카테고리
실마리 일지

KOSPI Surges +3.68% to 6,579.04 as Chips Lead — Korea Market Close, Aug 12, 2026

The KOSPI closed Wednesday, August 12 (2026) at 6,579.04, up 3.68%, after swinging across a 254.93-point intraday range (3.97%) between a session low of 6,413.50 and a high of 6,668.43.The KOSDAQ added 0.12% to close at 858.91, oscillating within a narrower 2.49% band — the two markets diverged shar

The Silmari
A daily data newsletter on the Korean stock market — silmari, ‘a clue: the loose end that unravels the knot’
④ Closing 16:002026.08.12 Wed · No. 10Sentiment gauge: Neutral (Neutral) — composite score 0.877; volatility proxy at 95th percentile, leverage-ETF share at 83rd percentile; no-trigger streak and retail-pressure sub-scores also elevated. Three inputs (credit, margin, short-surge) remain uncollected today.
④ Closing · published 16:00 KST · regular session confirmed at 15:30 KST · Note: flow figures are preliminary as published just after the close; the exchange’s confirmed figures appear in that day’s Final Edition (20:00 KST).
01 · VerdictRegular session confirmed 15:30 KST

verdict at the close

KOSPI Surges +3.68% to 6,579.04 as Chips Lead

The KOSPI closed Wednesday, August 12 (2026) at 6,579.04, up 3.68%, after swinging across a 254.93-point intraday range (3.97%) between a session low of 6,413.50 and a high of 6,668.43.The KOSDAQ added 0.12% to close at 858.91, oscillating within a narrower 2.49% band — the two markets diverged sharply in magnitude, with large-cap semiconductors on the KOSPI driving the session’s gains while small-cap names on the KOSDAQ traded in a far tighter range.

Key points
01Foreign investors posted Net PurchaseThe total value of shares bought by an investor group minus the total value sold in a given session; a positive figure means the group added exposure on balance.Tracking which group — foreign investors, institutions, or retail — is a net buyer on a given day is a primary lens for reading Korean market flow data. of ₩2,835.8bn on the KOSPI today (provisional, collected 15:52), snapping the one-week Net SaleThe total value of shares sold by an investor group minus the total value bought; a negative figure indicating the group reduced exposure on balance.The counterpart to net buying — the two figures sum to zero across all participants, so sustained net selling by one group must be absorbed by another. trend of ₩2,756.0bn; on the KOSDAQ they remained net sellers at ₩162.0bn.
02Semiconductors led: Samsung Electronics +6.68%, SK hynix +5.54%, Samsung Electro-Mechanics +5.78%, and SK Square +8.36% — together the two largest names turned over ₩13,697.0bn, accounting for the majority of KOSPI volume. Defense & aerospace and power-equipment sectors also posted gains above 3%.
03Morning call scorecard (provisional — final verdict in the 20:00 edition): P1 KOSPI direction ✓ but magnitude missed (actual +3.68% vs. called +0.5~+1.5%, △); P2 KOSDAQ ✓ (0.12% within –0.3~+0.5%); P3 Samsung Electronics △ (actual +6.68% vs. called +1~+2%); P4 SK hynix △ (actual +5.54% vs. called +1.5~+2.5%); P5 Jusung Engineering ✗ (actual +7.14% vs. called –2~+2%). All provisional — confirmed in final edition.
04The crash-precursor score stands at 2 out of a possible maximum (Advance-Decline RatioThe ratio of advancing stocks to declining stocks on a given exchange for a session; a reading above 1.0 means more stocks rose than fell.The ADR is used here as a market-breadth signal — a high index return driven by only a handful of large-caps can coexist with an ADR below 1.0, signalling narrow rather than broad participation. signal active; short-surge, sell-acceleration, and sentiment-90+ signals all inactive) — the gauge draws on data through August 11 (2026) for most components, with the ADR reference dated July 28 (2026).
03 · TimelineSnapshot — minute-bar readings

The day’s path

A window marking the hours when direction turned during the session

KOSPI Hit Session Low of 6,413.50 at 09:09, Peaked at 6,668.43 by 12:19, Then Faded to Close at 6,579.04

KOSPI snapshotOpen6435.6· High6668.43(12:19) · Low6413.5(09:09) · Last6579.04
KOSDAQ snapshotOpen853.01· High860.76(13:01) · Low839.86(09:30) · Last858.91
04 · 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

Nextrade Alternative Trading SystemKorea’s first alternative trading venue to KRX, operating pre-market, main, and after-market sessions and publishing a separate volume tally alongside the primary exchange.NXT data adds a supplementary read on how listed Korean stocks are trading outside KRX hours, and its market-share percentage reflects the pace of adoption of the alternative venue. Snapshot at 15:25 Showed Samsung Electronics and SK hynix Maintaining Day’s Gains with ₩78,213bn Combined

Top 10 by trading value — prior close · open · gap · high (time) · last · change · low (time)
StockPrior closeOpenGapHigh (time)CloseChangeLow (time)
Samsung Electronics239,501243,500+1.67%260,500 (12:14)255,500+6.68%241,000 (09:00)
SK hynix1,425,0521,456,000+2.17%1,549,000 (12:14)1,504,000+5.54%1,440,000 (09:12)
Samsung Electro-Mechanics1,262,0531,288,000+2.06%1,350,000 (12:20)1,335,000+5.78%1,275,000 (09:02)
SK Square944,998982,000+3.92%1,053,000 (12:31)1,024,000+8.36%970,000 (09:00)
LG Electronics181,705184,200+1.37%212,500 (10:45)205,000+12.82%184,200 (09:00)
Samsung Electronics (Pref.)180,207182,500+1.27%189,500 (12:17)186,100+3.27%180,500 (09:00)
Daewon Cable14,52015,100+3.99%16,080 (14:36)16,030+10.40%15,020 (09:00)
Hanwha Aerospace1,098,0241,116,000+1.64%1,191,000 (13:58)1,156,000+5.28%1,083,000 (09:09)
Korea Kolmar107,899114,100+5.75%139,300 (10:10)132,500+22.80%109,000 (09:14)
Kumho E&C11,49011,620+1.13%14,930 (10:53)14,930+29.94%11,340 (09:00)

At the NXT snapshot (20-minute delay, as of 15:25), Samsung Electronics and SK hynix showed gains of +6.68% and +5.33% respectively, consistent with KRX closing prints, with combined NXT turnover of ₩78,213bn across the two names.Intraday, the KOSPI session low of 6,413.50 was struck at 09:09, and the session high of 6,668.43 was printed at 12:19 — after which the index faded roughly 89 points into the close at 6,579.04, with Samsung Electronics reaching its intraday peak of ₩260,500 at 12:14.

05 · FlowsIn Korean won · KRX

Flow summary

A window on how much foreign investors, retail investors, investment firms and pension funds each bought and sold

Foreign Net Buying ₩2,835.8bn on KOSPI Today Reverses a One-Week Net Selling Streak

Foreign investors → retail · KOSPI (same-day correlation)Retail investors-0.846 (moves almost exactly opposite)· KOSPI0.511 (tends to move in the same direction)
Investment firms → retail · KOSPI (same-day correlation)Retail investors-0.629 (moves almost exactly opposite)· KOSPI0.601 (moves almost in lockstep)
Pension funds → retail · KOSPI (same-day correlation)Retail investors-0.188 (no clear relationship)· KOSPI0.017 (no clear relationship)
How to read the correlationCloser to +1 means they moved together; closer to −1 means they moved opposite — measured in the current regime (2026)
06 · Top 10Close · change · flows by four investor groups

The stocks that moved the market — top by turnover10

A window on which investor groups backed the most heavily traded stocks

Samsung Electronics and SK hynix Together Turned Over ₩13,697bn — Half the KOSPI’s Chip-Driven Volume

Samsung Electronics (₩6,868.8bn) and SK hynix (₩6,828.2bn) together accounted for roughly ₩13,697bn of KOSPI turnover — both names rose more than 5% on the session — while Samsung Electro-Mechanics (₩925.9bn, +5.78%) and LG Electronics (₩622.8bn, +12.82%) rounded out the KOSPI top five by value.

Top 10 by turnover (KOSPI)
StockCloseChangeTurnoverForeign investorsInstitutionsInvestment firmsPension fundsRetail investors
Samsung Electronics₩255,500+6.68%₩6.87tn+₩1.48tn+₩196.3bn+₩291.6bn−₩31.9bn−₩1.53tn
SK hynix₩1,504,000+5.54%₩6.83tn+₩852.2bn+₩288.8bn+₩176.7bn+₩43.6bn−₩1.14tn
Samsung Electro-Mechanics₩1,335,000+5.78%₩925.9bn+₩175.9bn+₩108.5bn+₩50.3bn+₩9.2bn−₩274.8bn
SK Square₩1,024,000+8.36%₩721.5bn+₩100.8bn+₩59.3bn+₩48.5bn+₩3.8bn−₩154.8bn
LG Electronics₩205,000+12.82%₩622.8bn+₩115.3bn+₩68.9bn+₩32.8bn+₩25.6bn−₩183.3bn
Samsung Electronics (Pref.)₩186,100+3.27%₩585.4bn−₩51.9bn+₩23.1bn+₩17.4bn+₩21.3bn+₩26.1bn
Daewon Cable₩16,030+10.40%₩411.3bn+₩15.2bn+₩9.5bn+₩0.1bn+₩0.2bn−₩25.0bn
Hanwha Aerospace₩1,156,000+5.28%₩348.9bn−₩19.3bn+₩12.0bn−₩6.8bn+₩13.0bn+₩4.4bn
Korea Kolmar₩132,500+22.80%₩329.4bn
Kumho E&C₩14,930+29.94%₩293.4bn
Historical contextForeign investors / institutions / investment firms / pension funds / retail investors · figures in Korean won · Source: KRX
07 · Up 5 · Down 5Reason labels: [News] confirmed · [Pattern] inferred

Gainers5· Decliners5KOSPI & KOSDAQ

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

Beauty and Chip Names Dominate KOSPI Gains; Shipbuilding and Biotech Weigh on Decliners

KOSPI
Gainers · relative strength5 (KOSPI)
Kumho E&C+29.94%[Pattern]Turnover ₩293.4bn · machine ranking
Kumho Electric+29.90%[Pattern]Turnover ₩17.3bn · machine ranking
Korea Kolmar+22.80%[Pattern]Turnover ₩329.4bn · machine ranking
Cosmax+18.81%[Pattern]Turnover ₩149.1bn · machine ranking
Iljin Electric+17.31%[Pattern]Turnover ₩102.0bn · machine ranking
Decliners5 (KOSPI)
Daelim Trading−13.25%[Pattern]Turnover ₩10.8bn · machine ranking
Kyungdong Navien−11.30%[Pattern]Turnover ₩31.0bn · machine ranking
Shinsegae−6.88%[Pattern]Turnover ₩75.0bn · machine ranking
OCI Holdings−6.40%[Pattern]Turnover ₩105.6bn · machine ranking
Hyundai Marine & Fire Insurance−5.45%[Pattern]Turnover ₩29.1bn · machine ranking
KOSDAQ
KOSDAQGainers5
Nam Hwa Construction+29.93%[Pattern]Turnover ₩44.9bn · machine ranking
MX Robotics+29.93%[Pattern]Turnover ₩18.0bn · machine ranking
J&TC+22.93%[Pattern]Turnover ₩19.4bn · machine ranking
Seosan+19.85%[Pattern]Turnover ₩91.1bn · machine ranking
Justek+19.85%[Pattern]Turnover ₩83.6bn · machine ranking
KOSDAQDecliners5
Delicious−26.57%[Pattern]Turnover ₩175.6bn · machine ranking
Pearl Abyss−14.50%[Pattern]Turnover ₩74.7bn · machine ranking
OliX−13.95%[Pattern]Turnover ₩73.7bn · machine ranking
L&C Bio−10.55%[Pattern]Turnover ₩21.8bn · machine ranking
BiQu AI−9.13%[Pattern]Turnover ₩10.3bn · machine ranking

On the KOSPI, the top-gaining names included Kumho Construction (+29.94%), Hankook Kolmar (+22.80%), Cosmax (+18.81%), and LG Electronics (+12.82%), spanning construction, beauty OEM, and electronics — a broad sectoral spread on the upside — while the steepest declines were concentrated in Daelim Tongsan (13.25%), Kyungdong Navien (11.30%), and OCI Holdings (6.40%).On the KOSDAQ, outsized gains in robotics and semiconductor-equipment names (MX Robotics +29.93%, J&TC +22.93%, Seozan +19.85%) contrasted with sharp drops in Delicious (26.57%), Pearl Abyss (14.50%), and Ollix (13.95%), suggesting the session’s strength was theme-specific rather than broad-based on this exchange.

08 · After lookas of 15:53 KST on 2026-08-12

After-Hours Outlook

A window on what to watch in after-hours trade once the regular session ends

Futures Board Points Mixed: Nikkei CME +0.49% Overnight, S&P 500 Futures –0.28% as of 05:00 KST

As of 05:00 KST, S&P 500 futures were down 0.28% and Nasdaq 100 futures were off 0.36%, while Nikkei CME futures showed a gain of 0.49% — a split overnight signal, with Korean-listed chips having already priced in significant upside today.In the 2026 regime, Wednesdays have produced KOSPI gains in 80% of sessions (n=30) with an average foreign net position of –₩175.3bn; today’s provisional foreign net buying of +₩2,835.8bn sits well above that Wednesday average, which the after-hours tape may help clarify as final investor data clears around 18:00–20:00 KST.

Sources: Korea Exchange · NXT · own measurements · regular session confirmed 15:30 KST · The Silmari editorial desk.
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.