Correction — 22 October 2026: The original article treated an October 8 Korean close as a fresh 4.54% decline. Its adjacent-session return was minus 2.62%. It also showed unchanged commodity prices and the wrong direction for the Nasdaq daily return. Those descriptions are corrected below. This is a retrospective review using daily history retrieved on 2026-10-22, not a live report or a reconstruction of every quote available at original publication.
A repeated quote is not another trading session
The archived KOSPI level of 6,625.93 belongs to October 8 in the provider history. Its previous available close is 6,803.90 on October 7. Reusing the same closing level in a later publication does not create another loss. This review retains that Korean observation alongside October 9 US data and labels each row explicitly.
Dated observations and calculations
| Series / source | Previous date | Previous value | Observation date | Value | Change | Time zone |
|---|---|---|---|---|---|---|
| KOSPI | 2026-10-07 | 6,803.90 | 2026-10-08 | 6,625.93 | -2.62% | Asia/Seoul |
| S&P 500 | 2026-10-08 | 7,765.36 | 2026-10-09 | 7,811.54 | +0.59% | America/New_York |
| Nasdaq Composite | 2026-10-08 | 27,193.34 | 2026-10-09 | 27,366.17 | +0.64% | America/New_York |
| US 10-year yield proxy (^TNX) | 2026-10-08 | 5.231 | 2026-10-09 | 5.244 | +1.3 bp | America/Chicago |
| WTI futures (CL=F) | 2026-10-08 | 91.49 | 2026-10-09 | 91.85 | +0.39% | America/New_York |
| Gold futures (GC=F) | 2026-10-08 | 4,157.00 | 2026-10-09 | 4,216.30 | +1.43% | America/New_York |
Zero in a snapshot is not proof of a flat market
The earlier input showed zero changes for WTI and gold. Comparing the October 9 observations with October 8 instead gives WTI plus 0.39% and gold plus 1.43%. A zero supplied by a data feed can reflect a comparison or refresh issue. It should not be turned into a statement that an asset ignored a headline without checking the actual reference observation.
Method and limits
Percentage changes use (value ÷ previous available daily value − 1) × 100, before rounding. Yield changes use the difference in percentage-point quotes multiplied by 100 to obtain basis points. Index levels are in points; futures quotes are in US dollars per barrel for WTI and per troy ounce for gold.
Each linked Yahoo Finance history is the data source for that row. These provider observations have not been independently checked against exchange settlement records. The futures series can change its referenced contract over time and should not be treated as the return on a continuously held investment. A date shared by two markets does not make their closing times simultaneous.
The earlier news-based explanations are omitted because their relevance to these measured moves was not established. For the calculation workflow and trading-session examples, see How to Read Daily Market Returns Without Mixing Trading Sessions.
