Correction and editorial revision — 23 October 2026: This retrospective replaces the earlier mixed-time narrative with dated provider observations. An index and currency snapshot did not establish semiconductor demand or foreign buying. The earlier causal explanations and trading implications are withdrawn; their removal is not a finding that every cited event was false. Historical closing observations can differ from the intraday quotes used in the earlier version.
This archive review uses observations available in the retrieved daily history on or before 2026-09-04. Each market has its own closing time. The question is: What Does a Won Quote Show About Korean Returns?
What changed in the calculation
- For KOSPI, the archived input reported +1.90%. Matching its quoted value to 2026-09-04 and comparing with 2026-09-03 gives +1.64% in the provider daily series.
- For S&P 500, the archived input reported +0.68%. Matching its quoted value to 2026-09-04 and comparing with 2026-09-03 gives -0.38% in the provider daily series.
- For Nasdaq Composite, the archived input reported +1.10%. Matching its quoted value to 2026-09-04 and comparing with 2026-09-03 gives -0.29% in the provider daily series.
- For Gold futures, the archived input reported -0.34%. Matching its quoted value to 2026-09-04 and comparing with 2026-09-03 gives -1.39% in the provider daily series.
The comparison above concerns the archived input and dated daily history. The table below uses a single stated cutoff with each instrument’s own preceding observation; it does not assert simultaneous prices. For the yield proxy, percentage changes in the quote are distinct from basis-point changes and from bond returns.
The measured comparison
USD/KRW moved from 1,358.39 on 2026-09-03 to 1,355.41 on 2026-09-04, a -0.22% change in won per dollar. Expressing the won’s dollar value instead requires taking the reciprocal: its change is +0.22%. Opposite quote conventions reverse direction and do not give exactly equal percentage magnitudes. USD/KRW history.
USD/JPY changed -2.05% over 2026-09-03–2026-09-04. Over five observation intervals, USD/KRW changed -1.81% and USD/JPY changed -2.30%. These are two currency pairs, not a broad dollar index or a yuan measure. KOSPI’s +1.64% daily return is a separate local-currency index observation, and does not identify foreign-investor purchases or intervention.
Reproducing the longer comparison
For USD/KRW, the five-interval baseline is 1,380.45 on 2026-08-28; the endpoint is 1,355.41 on 2026-09-04. The calculation is (endpoint ÷ baseline − 1) × 100 = -1.81%. This uses the endpoints directly rather than adding rounded daily percentages. Five observations need not correspond to one calendar week when a market is closed.
Source-linked daily observations
| Series | Previous date | Previous value | Date | Value | Change | Time zone |
|---|---|---|---|---|---|---|
| KOSPI (^KS11) | 2026-09-03 | 6,579.48 | 2026-09-04 | 6,687.21 | +1.64% | Asia/Seoul |
| S&P 500 (^GSPC) | 2026-09-03 | 7,747.71 | 2026-09-04 | 7,718.60 | -0.38% | America/New_York |
| Nasdaq Composite (^IXIC) | 2026-09-03 | 26,584.06 | 2026-09-04 | 26,506.99 | -0.29% | America/New_York |
| US 10-year yield proxy (^TNX) | 2026-09-03 | 4.762 | 2026-09-04 | 4.784 | +2.2 bp | America/Chicago |
| WTI futures (CL=F) | 2026-09-03 | 91.30 | 2026-09-04 | 91.48 | +0.20% | America/New_York |
| Gold futures (GC=F) | 2026-09-03 | 4,539.90 | 2026-09-04 | 4,476.60 | -1.39% | America/New_York |
| USD/KRW (USDKRW=X) | 2026-09-03 | 1,358.39 | 2026-09-04 | 1,355.41 | -0.22% | Europe/London |
| USD/JPY (USDJPY=X) | 2026-09-03 | 158.92 | 2026-09-04 | 155.66 | -2.05% | Europe/London |
| VIX (^VIX) | 2026-09-03 | 14.32 | 2026-09-04 | 14.53 | +1.47% | America/Chicago |
Scope and limitations
Returns are calculated before rounding from Yahoo Finance daily history, not independently verified exchange settlement records. Index values are in points; the yield proxy is quoted in percent; currency quotes are local units per US dollar; gold and WTI futures are dollars per ounce and barrel. Futures-series changes can reflect contract rolls and are not a continuously held contract’s investment return. These are retrospective observations, not live prices or a reconstruction of every intraday quote available to the original author.
For the underlying method, see the trading-session and return guide. This page retains its original address for correction transparency. The title and text now reflect the narrower evidence available; the old URL wording should not be treated as a current claim. No trading instruction is retained.
