Korea Market Close: KOSPI Drops 4.58% as Chips Slide

KOREA MARKET CLOSE

Heavy foreign and program selling hit chip megacaps and triggered a sell-side sidecar, while broader KOSPI breadth and the KOSDAQ proved more resilient.

Report cut-offAug. 6, 2026 20:50 KST Korean equities and USD/KRW15:30 KST close Overseas marketsChecked 20:50 KST

1. Closing view

Risk-off

Foreign cash selling and non-arbitrage program outflows concentrated in semiconductor megacaps drove a sharp KOSPI and KOSPI 200 decline and triggered a sell-side sidecar. Yet KOSPI advancers still outnumbered decliners and the KOSDAQ rose, pointing to concentrated large-cap de-risking and sector rotation rather than a uniform market collapse.

2. Key takeaways

The KOSPI closed at 6,296.38 (-4.58%), while the KOSDAQ ended at 801.67 (+0.26%) on Aug. 6.
The KOSPI 200 fell 5.36% and September futures lost 5.84%, showing that large-cap and derivatives stress exceeded the cash-index decline.
Foreign investors sold a net KRW 3.2893tn of KOSPI cash equities, while KOSPI program trading recorded a KRW 2.1257tn net outflow.
A sell-side sidecar was triggered at 10:18:12 KST, suspending program sell-order effectiveness for five minutes.
KOSPI advancers totaled 490 versus 381 decliners, diverging sharply from the index drop. The KOSDAQ rose even though decliners outnumbered advancers.
Samsung Electronics fell 6.30%, SK hynix 10.37% and SK Square 13.32%.
Day-session USD/KRW declined KRW 0.7 to 1,423.8 per dollar, so FX and foreign equity-flow signals did not align.

3. Indexes and market breadth

KOSPI6,296.38-301.88 (-4.58%)

Open: 6,478.75
High: 6,550.94
Low: 6,238.32
Volume: 284,501k shares
Turnover: KRW 26,452,137mn
Status: Closed

Aug. 6, 2026, 15:30 KST; index points, thousand shares and KRW mn; KRX data via Npay, final close; source; checked 20:50 KST.

KOSDAQ801.67+2.08 (+0.26%)

Open: 797.44
High: 813.54
Low: 779.08
Volume: 554,382k shares
Turnover: KRW 6,141,037mn
Status: Closed

Aug. 6, 2026, 15:30 KST; index points, thousand shares and KRW mn; KRX data via Npay, final close; source; checked 20:50 KST.

KOSPI 200982.92-55.67 (-5.36%)

Open: 1,016.93
High: 1,028.69
Low: 975.74
Volume: 149,108k shares
Turnover: KRW 24,344,161mn
Status: Closed

Aug. 6, 2026, 15:30 KST; index points, thousand shares and KRW mn; KRX data via Npay, final close; source; checked 20:50 KST.

KOSPI 200 futures Sep. 2026981.15-60.90 (-5.84%)

Open: 1,017.15
High: 1,030.80
Low: 978.25
Volume: 120,877 contracts
Value: KRW 30,026,483mn
Status: Closed

Aug. 6, 2026 close; points, contracts and KRW mn; KRX data via Npay; source; checked 20:50 KST.

Market breadth and limit-up/limit-down counts
Market	Up	Unchanged	Down	Limit up	Limit down	Reading
KOSPI	490	44	381	3	0	Advancers led despite the steep index decline
KOSDAQ	736	95	893	7	0	Decliners led despite a positive index close

Common basis: Aug. 6, 2026, 15:30 KST; stock counts; KRX data via Npay KOSPI and KOSDAQ; checked 20:50 KST. Limit-up names are included in advancers and limit-down names in decliners.

KOSPI 200 breadth was also positive at 136 gainers, four unchanged and 59 decliners. The gap between breadth and index performance underscores the disproportionate impact of heavyweight chip and holding-company losses.

4. Intraday timeline and turning points

09:00 open
Lower open after a U.S. technology pullbackThe KOSPI opened at 6,478.75 and the KOSDAQ at 797.44. The KOSPI started about 1.81% below its prior close.
Early morning; exact time unverified
KOSPI briefly reached 6,550.94 before selling intensifiedThe session high is verified, but no minute-level timestamp was assigned.
10:18:12
KOSPI sell-side sidecar triggeredKOSPI 200 futures met the trigger threshold, suspending the effectiveness of program sell orders for five minutes. This was not a full-market trading halt.
Morning; exact time unverified
Session lows reached 6,238.32 on the KOSPI and 779.08 on the KOSDAQChip megacaps and program selling weighed on the market. The exact sequence and timing of the lows were not invented.
Afternoon
KOSDAQ and non-chip sectors recoveredBiotechnology, cosmetics and nonferrous metals outperformed, while the KOSDAQ climbed as high as 813.54 and turned positive.
15:30 close
KOSPI slumped while KOSDAQ edged higherThe KOSPI lost 4.58% and the KOSDAQ gained 0.26%, capturing the split between heavyweight chip stress and sector rotation.

5. Foreign, institutional and retail flows

Cash-equity net buying (KRW 100mn)
Market	Retail	Foreign	Institutions	Reading
KOSPI	+33,367	-32,893	-1,214	Retail absorbed heavy foreign selling
KOSDAQ	+863	-2,481	+1,615	Institutional buying partly offset foreign selling
KOSPI 200	+32,944	-32,371	-1,336	Foreign outflows were concentrated in large caps

Common basis: Aug. 6, 2026, 15:30 KST; KRW 100mn; KRX data via Npay KOSPI, KOSDAQ and KOSPI 200; checked 20:50 KST.

Program trading and futures flows (KRW 100mn)
Category	Retail/arbitrage	Foreign/non-arbitrage	Institutions/total	Reading
KOSPI program	+1,753	-23,010	-21,257	Non-arbitrage selling was the key flow pressure
KOSDAQ program	+310	-2,034	-1,725	Program selling diverged from the index gain
KOSPI 200 futures	+135	+4,089	-4,140	Foreign cash selling contrasted with futures buying

Common basis: Aug. 6, 2026 close; KRW 100mn; KRX data via Npay KOSPI, KOSDAQ and futures; checked 20:50 KST. The three displayed futures groups exclude other participants and therefore need not sum exactly to zero.

6. Leading and lagging sectors; key stocks

Sector performance at the close
Group	Sector	Change	Up/flat/down	Reading
Leader	Nonferrous metals	+10.34%	20/3/17	Top of the rotation away from technology megacaps
Leader	Cosmetics	+5.58%	50/4/11	Buying shifted toward consumer exporters
Leader	Healthcare providers and services	+4.09%	21/1/8	Moved with biotech large-cap strength
Leader	Biotechnology	+3.89%	32/6/20	Helped defend the KOSDAQ
Laggard	Semiconductors and equipment	-8.03%	43/9/119	Moved with U.S. tech caution and foreign selling
Laggard	Electronic equipment and instruments	-7.45%	33/7/66	Volatility surged after the prior session’s rally
Laggard	Electrical equipment	-4.14%	9/1/25	Profit-taking spread to capital-goods names

Common basis: Aug. 6, 2026 close; Npay sector taxonomy; source; checked 20:50 KST. Sector moves and headlines are treated as co-movement, not verified causality.

Large-cap and leading stocks at the close (prices in KRW)
Market	Stocks	Close	Change	Market relevance
KOSPI	Samsung Electronics / SK hynix	230,500/1,495,000	-6.30%/-10.37%	Chip megacaps drove the index decline
KOSPI	SK Square / Samsung Electro-Mechanics	970,000/1,229,000	-13.32%/-9.37%	Selling spread to chip holdings and components
KOSDAQ/KOSPI	Alteogen / Celltrion	293,500/195,000	+5.96%/+2.47%	Biotech large caps outperformed
KOSPI	Hanwha Aerospace / LG Energy Solution	1,054,000/345,000	+4.67%/+2.83%	Defense and batteries provided diversified support

Common basis: Aug. 6, 2026, 15:30 KST; closing prices in KRW; KRX data via Npay stock pages and close reports; checked 20:50 KST. Price and return pairs use compact slash notation without spaces.

Index contribution: The KOSPI decline reflected the outsized weights and losses of Samsung Electronics, SK hynix and SK Square more than the number of falling stocks. A same-basis official contribution ranking was not obtained, so the reading is limited to price and index-weight concentration.

7. Corporate and policy events

Confirmed fact

KOSPI sell-side sidecar triggered

At 10:18:12 KST, KRX suspended the effectiveness of program sell orders for five minutes after KOSPI 200 futures met the trigger threshold. It was not a circuit breaker or full-market halt.

Yonhap

Confirmed fact

Bank of Korea released provisional June balance-of-payments data

The BOK posted its provisional June 2026 balance-of-payments release on Aug. 6. Because the webpage summary contains a month-label inconsistency, this report does not repeat the headline figure and instead links to the official attachments.

Bank of Korea

Confirmed fact

July FOMC held rates at 3.50%-3.75%

The Fed kept its target range unchanged on July 29. Three voters preferred a 25bp increase, leaving inflation and the rate path relevant to growth-stock valuations.

Federal Reserve

Verification limit

No single filing established as the cause of the chip selloff

A priority review of DART and company disclosure routes did not identify one new filing that directly explained the day’s declines in Samsung Electronics, SK hynix or the broader chip group.

DART

Market interpretation: A sidecar is a volatility-control mechanism responding to rapid futures and program moves. It should be read as evidence that selling crossed the trigger threshold, not as the cause of the decline.

8. Overseas operations and international market reaction

Overseas signals and potential Korean corporate linkages
External signal	Verified value	Status	Korean exposure	Interpretation	Source
U.S. technology and chips	SOX -1.40% Nasdaq -0.83%	Aug. 5 close	Samsung Electronics, SK hynix, HBM, DRAM and equipment	U.S. tech caution moved with foreign selling in Korea	Npay SOX
U.S. AI-stock divergence	NVDA +3.4% Alphabet -4.0%	Aug. 5 close	AI-server memory demand and platform-customer capex	AI demand expectations persisted, but earnings and valuation caution widened	AP
Asian risk appetite	Nikkei -0.9% Hang Seng -1.5% Shanghai +0.6%	Aug. 6 close	Electronics, China consumption and Hong Kong financial exposure	Mixed regional performance argues against a single Asia-wide shock	AP
Crude oil	WTI $75.22	Aug. 5 close	Airlines, chemicals and transport costs; refining and shipbuilding margins	Lower oil helps cost-sensitive sectors but has mixed implications for energy names	Npay market indicators

Checked: Aug. 6, 2026, 20:50 KST. These links are business-exposure and price co-movement analysis; companies did not officially identify them as the sole cause of the day’s moves.

9. USD/KRW and JPY/KRW

Foreign-exchange summary
Pair	Value	Change	Basis	Source	Industry relevance
USD/KRW	KRW 1,423.8	-KRW 0.7	Aug. 6, 2026, 15:30 KST day-session close; won per U.S. dollar	Seoul FX market report	A firmer won can ease import costs but may weigh on translated export earnings
JPY/KRW	KRW 901.68	-KRW 0.64	Aug. 6, 2026, 20:50 KST Hana Bank reference rate; won per JPY 100	Hana Bank via Npay	A stronger won versus yen can reduce Korean auto and machinery pricing advantages; implications for tourism, duty-free and airlines are mixed

Checked: Aug. 6, 2026, 20:50 KST. JPY/KRW is not a 15:30 market close. It is a direct Hana Bank reference quote; no mismatched-time cross-rate was calculated.

Flow divergence: USD/KRW declined even as foreigners sold KOSPI cash equities heavily. FX and equity flows therefore did not point in the same direction, and the won move is not attributed solely to stock-market flows.

10. U.S., Asian, futures, oil and rates linkage

Global market summary
Group	Indicator	Value	Change	Data basis	Korea linkage
U.S. equities	Dow / S&P 500 / Nasdaq / SOX	54,349.12 7,723.55 26,363.44 12,008.88	+0.49% -0.17% -0.83% -1.40%	Aug. 5, 2026 local close; index points	Technology and chip weakness moved with caution in Korean megacaps
U.S. Treasuries	2-year / 10-year	4.18% 4.63%	Daily change not stated	Aug. 5, 2026, U.S. Treasury 15:30 ET CMT	Elevated yields continue to pressure growth-stock discount rates
Federal Reserve	Federal funds target range	3.50%-3.75%	Held July 29	July 29, 2026 FOMC decision	Hawkish dissents leave valuation risk for high-multiple growth stocks
Commodities and dollar	WTI / Brent / DXY	$75.22 $79.50 99.54	-$0.55 less than +0.1% -0.19	WTI and DXY Aug. 5 close; Brent intraday at 20:50 KST Aug. 6	Oil stability helps import costs; Brent is not a closing quote
Asia	Nikkei / Shanghai / Hang Seng	65,683.26 3,900.35 25,530.28	-0.9% +0.6% -1.5%	Aug. 6, 2026 close	Mixed regional moves highlight Korea-specific large-cap flow pressure
U.S. futures	S&P 500 / Dow / Nasdaq-100	+0.1% +0.3% Unverified	Intraday	Checked Aug. 6, 2026, 20:50 KST	Pre-open rebound attempt; not described as a close

Source mapping and check time: U.S. indexes: Npay Dow, S&P 500, Nasdaq and SOX; Treasury yields: U.S. Treasury; FOMC: Federal Reserve; WTI and DXY: Npay market indicators; Brent, Asia and U.S. futures: AP. Checked Aug. 6, 2026, 20:50 KST.

11. Next-session watchlist

Foreign cash and program selling: Whether the KRW 3.29tn KOSPI cash outflow and KRW 2.13tn program outflow ease.
Semiconductor follow-through: Whether Samsung Electronics and SK hynix narrow losses and U.S. chip indicators stabilize.
Sidecar recurrence: Whether KOSPI 200 futures and the cash-futures basis again approach the trigger threshold.
Breadth durability: Whether positive KOSPI breadth and rotation into cosmetics, biotech and nonferrous metals persist.
USD/KRW near 1,420: Whether won stability continues despite foreign equity selling.
U.S. employment and rates: How the scheduled jobs data affects 2-year and 10-year yields and growth-stock valuations.

12. Risks and data limitations

Data not verified or excluded

Same-basis final official data were not obtained for individual-stock VI events, a circuit breaker, trading halts, block trades, short-selling spikes, margin-call or leveraged-liquidation amounts, or closing-auction anomalies; none is asserted absent.
The KOSPI sell-side sidecar is confirmed, but exact minute-level high and low timestamps and the full sequence of intraday turning points were not verified.
JPY/KRW is a 20:50 KST Hana Bank direct reference rate, not the 15:30 Seoul FX market close.
No reliable synchronized Nasdaq-100 futures quote was obtained. S&P 500 and Dow futures and Brent are 20:50 KST intraday values, not closes.
The BOK June balance-of-payments webpage contains a month-label inconsistency in its summary, so the headline figure was not used without rechecking the official attachment.
No DART or company filing was verified as the sole cause of the chip selloff; the report is limited to global signals, flows and price co-movement.

Causality caution: U.S. technology weakness, foreign and program selling and chip declines moved in the same direction, but no company or exchange identified one official cause for the day’s prices. The report therefore uses co-movement, possible linkage and market interpretation language.

13. Overall assessment

Market temperatureRisk-off

Session quality2/5

Flow durabilityLow

VolatilityHigh

Nature of the move

The session looked less like a uniform fundamental collapse driven by one confirmed earnings downgrade and more like a combination of U.S. technology caution, foreign cash selling, non-arbitrage program liquidation and position reduction in recently strong megacaps. The sidecar shows that volatility reached its formal trigger.

Breadth versus concentration

KOSPI advancers outnumbered decliners despite a 4.58% drop, and KOSPI 200 breadth was positive. Conversely, the KOSDAQ rose even though decliners led. Both markets showed a material disconnect between index direction and breadth, highlighting the influence of heavyweight chips and biotech leaders.

Flow and FX alignment

Foreign KOSPI cash selling and program outflows aligned with risk-off conditions, but foreigners bought futures and USD/KRW declined. Cash, derivatives and FX did not fully align, making a simple broad foreign-capital-exit narrative incomplete.

Continuation and failure conditions

Stabilization requires smaller chip losses, easing foreign cash and program selling, no repeat sidecar and a stable won. Further U.S. chip weakness, renewed non-arbitrage outflows, deteriorating breadth and a reversal to won weakness would raise the probability of a longer correction.