The Silmari
A daily data newsletter on the Korean stock market — silmari, ‘a clue: the loose end that unravels the knot’
01 · Monday brief
Monday Preview — the weekend in brief
A window setting out only what is needed on Monday morning before the week turns
Philadelphia Semiconductor IndexA market-capitalization-weighted index of 30 companies primarily involved in the design, distribution, manufacture, and sale of semiconductors, published by Nasdaq.SOX moves of 0.5% or more overnight have historically corresponded with same-direction KOSPI opens, making it one of the most-watched pre-market signals for Korean chip stocks. +2.56%, iShares MSCI South Korea ETFA U.S.-listed exchange-traded fund tracking the MSCI Korea Index, providing foreign investors with liquid, dollar-denominated exposure to South Korean equities.EWY’s after-hours price is often used as a real-time proxy for offshore sentiment toward Korean stocks before the Seoul market opens. +1.20% — Wall Street’s Friday Rally Sets a Constructive Tone for Monday’s Open
Chips Lead Wall Street Higher; KOSPI Enters Monday After a -5.1% Weekly Slide
The weekend in brief
01The Philadelphia Semiconductor Index closed Friday at 12,356.79, up 2.56%, while the Nasdaq rose 1.30% to 26,690.62 and the S&P 500 gained 0.62% to 7,757.64.
02The Korea ETF (EWY) added 1.20% to 166.09 on Friday; the U.S. Dollar Index (DXY)A geometrically weighted index measuring the value of the U.S. dollar against a basket of six major currencies, with the euro carrying the largest weight.A weaker dollar index generally reduces currency headwinds for Korean exporters and can support foreign inflows into Korean equities priced in won. slipped 0.37% to 99.6 and the 10-year Treasury yield eased 0.21% to 4.66%.
03The KOSPI ended last week at 6,258.77, down 5.1% for the week (ranked 26th of 31 weeks in 2026 by weekly return); the KOSDAQ gained 10.98% for the week (ranked 2nd of 31 weeks).
04In the 2026 regime (28 Monday sessions), the KOSPI has averaged −0.50% on Mondays with a 57% advance rate and an average intraday range of 3.46%.
Wall Street’s Friday session delivered broad gains led by semiconductors, lifting the Korea ETF above 166 — a constructive external backdrop heading into a week that saw the KOSPI swing nearly 10 percentage points from peak to trough.Foreign investors were net sellers of ₩2.87tn on the KOSPI last week, while retail investors absorbed ₩3.26tn on the buy side; the sentiment gauge closed Friday in the “Anxiety” stage with a score of 1.227.
02 · US Friday close
US Friday session confirmed
A window on where the US finished while Korea was closed
Nasdaq +1.30%, SOX +2.56% Friday — Dollar Index Slips to 99.6 as Yields Ease
Closes and changes are confirmed U.S. Friday-session figures (early Saturday KST)
| Measure | Close | Change | Meaning |
|---|---|---|---|
| Nasdaq | 26,690.62 | +1.30% | U.S. tech — the first signal for Korean chips on Monday |
| S&P500 | 7,757.64 | +0.62% | The broad U.S. market’s temperature |
| SOX semiconductors | 12,356.79 | +2.56% | U.S. semiconductors — the overseas index closest to KOSPI |
| Dow | 54,036.93 | +0.28% | U.S. blue chips |
| EWY (Korea ETF) | 166.09 | +1.20% | Korea as seen from the U.S. — a leading read on foreign sentiment |
| Dollar index | 99.6 | −0.37% | A stronger dollar is a headwind for foreign inflows |
| U.S. 10-year Treasury | 4.66 | −0.21% | Rates — higher is a headwind for growth stocks |
| Nikkei 225 (prior session) | 65,606.71 | −0.12% | Japan’s Friday close — an Asia-sync reference |
| USD/KRW (prior Seoul session) | 1,422.3 | +0.08% | The won — a stronger won favors foreign buying |
Friday’s U.S. session ended with the Philadelphia Semiconductor Index up 2.56% to 12,356.79, the Nasdaq up 1.30%, and the S&P 500 up 0.62%; the dollar index fell 0.37% to 99.6 and the 10-year Treasury yield declined to 4.66%.In the 2026 year-to-date sample, overnight SOX moves of 0.5% or more have corresponded with same-direction KOSPI moves on 39 of 139 tracked sessions in the “Korea follows U.S.” pattern, while both markets moved together in both directions on 46 sessions — directional follow-through is possible but not the modal outcome.The softer dollar and lower yields reduce one headwind for Korean assets, though the won closed Friday’s Seoul session at 1,422.3 per dollar, up 0.08% on the day, and currency direction at Monday’s open remains an independent variable.
03 · Weekend wire
Weekend news — home and abroad
A window on the news that came over the weekend and what it means for Monday
SOX +2.56%, EWY +1.20% — semis and Korean ETF close higher Friday as dollar slips; KOSPI ends week down 5.1%, KOSDAQ up 11.0%
| Date | Layer | News | Implication |
|---|---|---|---|
| 08.09 (Sun) 03:22 | Industry | Nvidia eyes AI infrastructure…invests ₩4tn in power company Lancium (Yonhapnews·International) | AI data center power/infrastructure demand theme may be cited in domestic related stocks Monday, though individual stock reactions may not align with news direction, making definitive calls difficult. |
| 08.09 (Sun) 06:05 | Industry | Samsung Electronics Recruits First Interns at US Taylor Fab…Foundry Expansion Speed Race (Yonhap·Industry) | How foundry expansion news reflects in Samsung Electronics’ stock price warrants close watch alongside last week’s semiconductor supply flow (foreign Net SaleThe total value of securities sold by an investor category minus the total value purchased over a given period.Persistent foreign net selling, as seen last week (₩2,874.6bn), is watched as a potential overhang on index direction, particularly when retail absorption is the offsetting force.). |
| 08.09 (Sun) 06:20 | Industry | Retail Investors Exceed ₩200.0tn Net Buying in Domestic Stock Market This Year (Yonhap·Securities) | News aligns with last week’s retail Net PurchaseThe total value of securities purchased by an investor category minus the total value sold over a given period.Net buying and net selling by foreigners, institutions, and retail investors are the primary flow metrics used to assess who is driving — or absorbing — market moves on the KOSPI and KOSDAQ. of ₩3.2639tn flow; whether this trend continues Monday remains open. |
| 08.09 (Sun) 06:45 | Industry | Amazon Data Center Power Plant Investment Stirs Controversy…”Will Become US’s Top Polluter” (Yonhap·International) | If environmental regulatory risk from AI infrastructure expansion is highlighted, related sectors may be affected complexly, though near-term stock price impact direction is uncertain. |
| 08.09 (Sun) 17:45 | Policy | Government to Revise ‘ISA·Stock Price Suppression Prevention Act’…”Active Supplementation Under Review” (Roundup) (Yonhap·Politics) | Reads as retail investor-friendly regulatory refinement, but unconfirmed legislative timeline and specifics make Monday market reaction difficult to gauge in advance. |
| 08.09 (Sun) 05:31 | Policy | Government to Accelerate Supply of 27,000 Units in Seoul Semi-Industrial Zones (Yonhap·Economy) | As construction/real estate policy signal, may be cited in Monday construction stock supply/demand, though warrants viewing alongside last week’s construction sector flow. |
| 08.09 (Sun) 05:45 | Policy | Real Estate Tax Bill Legislative Opinions Flood In…Government Deliberates ‘Non-Resident Exception Criteria’ (Yonhap·Politics) | As tax uncertainty persists, whether direct impact appears in real estate related stocks requires further monitoring of legislative progress. |
Nvidia eyes AI infrastructure…invests ₩4tn in power company Lancium (Yonhapnews·International)
Samsung Electronics Recruits First Interns at US Taylor Fab…Foundry Expansion Speed Race (Yonhap·Industry)
Retail Investors Exceed ₩200.0tn Net Buying in Domestic Stock Market This Year (Yonhap·Securities)
Amazon Data Center Power Plant Investment Stirs Controversy…”Will Become US’s Top Polluter” (Yonhap·International)
Government to Revise ‘ISA·Stock Price Suppression Prevention Act’…”Active Supplementation Under Review” (Roundup) (Yonhap·Politics)
Government to Accelerate Supply of 27,000 Units in Seoul Semi-Industrial Zones (Yonhap·Economy)
Real Estate Tax Bill Legislative Opinions Flood In…Government Deliberates ‘Non-Resident Exception Criteria’ (Yonhap·Politics)
Scope of collectionCollection window 08.08(Sat) 12:00 ~ 08.09(Sun) 21:49 · Yonhapnews RSS 5 categories (Economy·Securities·Industry·Politics·International) · Implications subject to interpretation
04 · Monday watchlist
Monday watch list
A window setting out what to look at first on Monday morning
Monday Watch: 57% Advance Rate in 2026, Average Move −0.50% — Pre-Signal Score Reads 3
Monday 2026 regime28 sessions: avg return −0.50%, advance rate 57%, avg intraday range 3.46%
Pre-signal score (Friday)Score 3 — Advance-Decline RatioThe ratio of advancing issues to declining issues on an exchange over a given period, used to gauge the breadth of a market move.An ADR reading that diverges sharply from the index level can signal that a headline move is narrowly driven rather than broad-based, which feeds into the pre-signal scoring model used here. triggered (2 pts), short-selling surge (1 pt); note: includes delayed-disclosure signals, treat as preliminary until Monday morning recalculation
Sentiment gaugeStage: Anxiety; composite score 1.227; vol20 percentile 97, Leveraged Fund ShareThe proportion of total equity fund assets held in leveraged (2x or higher) long products, used here as a sentiment proxy.At the 97th percentile of the 2026 year-to-date range, leverage share is among the highest readings in this regime, indicating elevated speculative positioning that can amplify downside moves. percentile 97, pbuy_down percentile 71, notrigger_streak percentile 85; credit5d, margin, short_surge not collected this cycle
SOX–KOSPI follow-through (2026 YTD)Korea follows U.S. (|SOX|≥0.5%): 39 of 139 sessions; bidirectional: 46; no-follow: 24; U.S. follows Korea: 30
EWY & dollar contextEWY +1.20% to 166.09; dollar index −0.37% to 99.6; USD/KRW 1,422.3 (+0.08%) as of Friday Seoul close
The 2026 Monday regime shows a 57% advance rate, but the average return of −0.50% and average range of 3.46% across 28 sessions indicate that even “up” Mondays have tended to be volatile.With the pre-signal score at 3 and the sentiment stage in Anxiety, multiple inputs are pulling in different directions; the judgment is each reader’s own.
05 · Lessons carried
What we carry from last week
A window for what to carry from last week into next
From Last Week: A −5.1% KOSPI Slide, a +10.98% KOSDAQ Surge, and ₩2.87tn in Foreign Net Selling
KOSPI weekly return−5.1% for the week ending Aug 7; ranked 26th of 31 weeks in 2026; closing level 6,258.77; intraday high-low range 9.78% (ranked 17th of 32 weeks)
KOSDAQ weekly return+10.98% for the week; ranked 2nd of 31 weeks in 2026; closing level 798.81; intraday high-low range 15.56% (ranked 7th of 32 weeks)
Weekly net flowsForeigners −₩2,874.6bn; retail +₩3,263.9bn; investment trusts −₩242.2bn; pension funds +₩105.1bn
Daily headlines (last week)Mon: KOSPI −5.12%, KOSDAQ +2.44% — sector rotation; Tue: KOSDAQ +5.88%, KOSPI +1.62%; Wed: KOSPI +3.76% on SOX surge; Thu: KOSPI −4.58% semiconductor-led drop; Fri: KOSPI −0.60%, energy and defense bought as chips sold
Last week’s split between a sharply lower KOSPI and a surging KOSDAQ, combined with heavy foreign net selling absorbed almost entirely by retail investors, leaves Monday’s session opening against an unsettled positioning backdrop.The judgment is each reader’s own.