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KOSPI posts weekly gain of +11.49%, closing Friday at 6,977.94 — Korea Market Week in Review, Aug 15, 2026

The week opened quietly — Monday and Tuesday each added less than 1% — before semiconductors ignited a two-day surge of +3.68% Wednesday and +3.56% Thursday, driven by heavy foreign net buying on both days.Friday’s session added a further +2.42%, led by autos and telecoms, carrying the KOSPI to 6,97

The Silmari
A daily data newsletter on the Korean stock market — silmari, ‘a clue: the loose end that unravels the knot’
◈ Weekend Silmari — Week in Review 12:002026.08.15 Sat · No. 13Neutral — composite sentiment score 0.678 as of Friday, August 14 (2026); 20-day volatility at 5.88 (93rd percentile, 2026 regime), leverage share at 9.81% (71st percentile); three inputs (credit balance, margin debt, short-sale residual) carry publication lags and reflect data through August 12–13 (2026) at the latest.
◈ Weekend — Week in Review · published 12:00 KST · week ended Friday
01 · Weekly verdictAs of Friday (08.14) close — confirmed

This week in review

A window on where the market moved over the week

KOSPI posts weekly gain of +11.49%, closing Friday at 6,977.94

Foreigners Buy, Korea Rallies — KOSPI Surges +11.49% in Five Sessions

Headlines by day — the week in five sentences
Mon (08.10)KOSDAQ surges +6.97%, KOSPI closes +0.65% amid 161p range
Tue (08.11)Philadelphia Semiconductor IndexA US equity index tracking the performance of approximately 30 semiconductor and semiconductor-equipment companies listed on US exchanges.SOX moves overnight often set the tone for Korean semiconductor stocks — SK hynix and Samsung Electronics in particular — at the Seoul open.Downturn forecast missed as Samsung Electronics lifts market
Wed (08.12)Semiconductor spark — KOSPI +3.68%, foreigners net buy ₩2.8354T
Thu (08.13)KOSPI +3.56% surge, breaks forecast high — KOSDAQ modest +0.29%
Fri (08.14)KOSPI +2.42% sharp rebound, autos and telecom lead to 6,977.94 close

The week opened quietly — Monday and Tuesday each added less than 1% — before semiconductors ignited a two-day surge of +3.68% Wednesday and +3.56% Thursday, driven by heavy foreign net buying on both days.Friday’s session added a further +2.42%, led by autos and telecoms, carrying the KOSPI to 6,977.94 at the close.The week’s +11.49% gain ranked 2nd out of 32 weeks tracked in the 2026 regime; the intraweek high-low swing of 12.83% ranked 8th out of 33 weeks.

02 · Weekly numbersAs of Friday (08.14) close — confirmed

The week in numbers

A window measuring the week’s change, its range and where it sits within the year

KOSPI closes the week at 6,977.94, up +11.49%; KOSDAQ at 864.65, up +8.24%

Week = Monday open through Friday close · ranks vs. completed weeks of 2026 · source: FinanceDataReader
ItemKOSPIKOSDAQRank this year
Weekly change+11.49%+8.24%KOSPI: rank 2 of 32 weeks
Weekly high–low range+12.83%+8.87%KOSPI: rank 8 of 33 weeks
Friday close6,977.94864.65
Against the pastThe KOSPI’s weekly gain of +11.49% ranked 2nd out of 32 weeks in the 2026 dataset; the intraweek range of 12.83% ranked 8th out of 33 weeks.The KOSDAQ’s +8.24% weekly advance ranked 3rd out of 32 weeks, while its high-low swing of 8.87% ranked 19th out of 33 weeks — wider in magnitude but more middling in relative volatility compared with the large-cap index.
03 · Weekly flowsAs of Friday (08.14) close — confirmed

Weekly flows — who bought and who sold

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

Foreigners net bought ₩6,546.9bn for the week; retail investors net sold ₩7,084.6bn

KOSPI market net buying · in won · source: Korea Exchange
DayKOSPIForeign investorsRetail investorsInvestment firmsPension funds
Mon (08.10)+0.65%−₩1.49tn+₩900.3bn+₩581.6bn−₩144.9bn
Tue (08.11)+0.73%+₩53.5bn−₩70.8bn+₩62.8bn−₩42.6bn
Wed (08.12)+3.68%+₩2.84tn−₩3.19tn+₩523.1bn−₩28.1bn
Thu (08.13)+3.56%+₩2.11tn−₩2.74tn+₩508.2bn−₩64.1bn
Fri (08.14)+2.42%+₩3.04tn−₩1.98tn−₩1.06tn+₩39.1bn
Weekly total+11.49%+₩6.55tn−₩7.08tn+₩617.0bn−₩240.6bn

Foreign investors were net buyers every day of the week, accelerating from a net sale of ₩1,490.9bn on Monday to net purchases of ₩2,835.4bn Wednesday, ₩2,110.2bn Thursday, and ₩3,038.7bn Friday, for a weekly total of ₩6,546.9bn.Retail investors absorbed the other side, net selling ₩7,084.6bn over the five sessions — their heaviest offloading concentrated on Wednesday (₩3,191.1bn) and Thursday (₩2,741.0bn).Institutional investors were modest net buyers at ₩617.0bn for the week, though they turned net sellers on Friday (₩1,058.7bn); the National Pension Service was a net seller of ₩240.6bn on the week.

Past patternNo cross-asset correlation statistics were included in this week’s dataset.What the data do show: on the two strongest KOSPI sessions (Wednesday +3.68% and Thursday +3.56%), foreign net buying ran at ₩2,835.4bn and ₩2,110.2bn respectively — the two largest single-day foreign inflows of the week.
04 · Actor stocksWeekly totals · as of Friday (08.14) close

What each group bought and sold

A window on the stock each group bought most and sold most that week

Foreigners concentrated buys in Samsung Electronics (₩3,936.8bn); retail bought Jeju Semiconductor, sold Samsung Electronics

Top and bottom stocks by weekly net buying · in won · source: Korea Exchange
Investor groupBought mostSold most
Foreign investorsSamsung Electronics+₩3.94tnSamsung Electro-Mechanics−₩152.6bn
Retail investorsJeju Semiconductor+₩81.0bnSamsung Electronics−₩3.39tn
Investment firmsSamsung SDI+₩43.3bnSK hynix−₩296.8bn
Pension fundsSK hynix+₩103.9bnSamsung Electronics−₩103.1bn

Samsung Electronics was the clearest point of divergence: foreigners were the week’s largest net buyers at ₩3,936.8bn, retail investors were the largest net sellers at ₩3,385.1bn, and the National Pension Service also net sold ₩103.1bn of the same name.Meanwhile, institutional investors net sold SK hynix (₩296.8bn) while the National Pension Service net bought it (₩103.9bn), adding another cross-actor split on a single name; the universe covered is 70 stocks.

SampleSample: 70 tracked names by turnover — not a full-market total.
05 · Weekly eventsCollected from Yonhap RSS · five-layer classification

The week’s events

A window on what moved the market over the week and what followed, in order

Semiconductor capex confirmation and domestic AI policy dominated the week’s headline flow

Result = that day’s KOSPI change (no single-cause attribution — overlapping drivers move together)
DayLayerEventOutcome
MonIndustrySemiconductor equipment stocks surge on confirmed SK hynix investment scaleKOSPI +0.65%
MonIndustryIntel raises equity capital for AI investment — first public offering since listing, targeting ₩21tnKOSPI +0.65%
MonIndustryPresidential office announces Chungcheong-region ₩246tn and Yeongnam-region ₩107tn investment projects to begin this yearKOSPI +0.65%
MonPolicyGovernment to significantly expand physical-AI procurement to grow robotics ecosystemKOSPI +0.65%
MonPolicyPOSCO files rebuttal with Japanese government over anti-dumping duty on galvanized steel sheetKOSPI +0.65%
MonIndustry90% of SNU Engineering broad-track entrants choose electrical and information engineering — semiconductor and AI influence citedKOSPI +0.65%
MonIndustryKorea East-West Power and ROAS sign cooperation agreement for robot-based AI technology development and demonstrationKOSPI +0.65%
MonPolicyPresidential office announces mega-special-zone legislation to be enacted this year; inter-ministerial council to be set under PMKOSPI +0.65%
TueIndustrySemiconductor export surge cited as earnings momentum — Samsung Electronics +4%, SK hynix +0.35%KOSPI +0.73%
TueIndustryNAVER D2SF makes follow-on investment in physical-AI start-up N.LightKOSPI +0.73%
06 · Wall St. scoreboardStance vs. actual three trading days later · cumulative scoring

Wall Street scoreboard — weekly summary

A window grading, cumulatively, whether the stance of US investment bank reports matched reality three days later

Wall Street Scoreboard: 14 hits in 26 calls since tracking began (54%); no new verdicts this week

The scoreboard tracks buy- and sell-side calls on Korean equities, scoring each against the stock’s three-day return after publication; the current cumulative record stands at 14 hits out of 26 graded calls (54%), with no new calls added or graded this week.Among the five calls shown in the grading panel, directional accuracy has been mixed: a Bernstein upgrade on Samsung Electronics scored +1.41% three days later, while a Barclays target raise on SK hynix (upside cited: 117%) was followed by a -19.23% three-day return — the scoreboard logs both.

InstitutionsReportActualVerdict
Bernstein (06.22)Samsung Electronics—Bernstein raises targets for Samsung, SK Hynix, Micron…”Rising memory prices ease AI cost pressures” (Positive)+1.41%
Nomura (06.24)Samsung Electronics—Nomura “590K→670K”…Samsung target raised again (Positive)−5.14%
JPMorgan (06.25)KOSPI—JPMorgan raises 12-month target to 12,500…”Maximize Korean equity weight” (Positive)−5.08%
Morgan Stanley (07.13)SK Hynix—Semiconductor overbought warning (memory winter precedent) (Negative)−0.16%
Barclays (07.23)SK Hynix—Target price $330 (117% upside) (Positive)−19.23%
CumulativeCumulative: 14 of 26 calls correct (54%) · no newly scored reports this week — showing the last 5 verdicts
07 · LessonsAs of Friday (08.14) close

The week’s lesson

A window for what to carry past the end of the week

Five sessions, four takeaways — what this week’s data record

Divergence on SamsungForeigners net bought ₩3,936.8bn of Samsung Electronics for the week while retail investors net sold ₩3,385.1bn of the same name — the single clearest cross-actor split in the 70-stock universe.
Acceleration patternForeign daily net buying went from a net sale on Monday to ₩3,038.7bn on Friday; the two largest inflow days (Wednesday and Thursday) coincided with the two largest single-day KOSPI gains (+3.68% and +3.56%).
Wall Street call riskThe scoreboard’s 54% hit rate (14/26) over the tracked period is a reminder that directional calls — including a 117%-upside target that was followed by a -19.23% three-day return — do not reliably predict near-term price direction.
Sentiment gauge lagThree of the seven sentiment inputs (credit balance, margin debt, short-sale residual) carry publication lags of T+1 or T+2, meaning Friday’s composite score of 0.678 (‘Neutral’) is partly based on data as old as Wednesday, August 12 (2026).

The week’s data capture a sharp rally driven by concentrated foreign buying, a clean retail-vs-foreigner split on the market’s largest stock, and a Wall Street scoreboard that continues to track both its hits and its misses.The judgment is each reader’s own.

Sources: Korea Exchange · FinanceDataReader · verified · as of Friday (08.14) close (confirmed) · The Silmari 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.