Quieter, yes. Biased, no.
Movement genuinely drops in 12 of 19 markets across the whole summer, while only 1 of 19 shows a directional difference. The thinness is real and extends beyond August alone.
| Market | In the window | Rest | z | Movement | Samples |
|---|---|---|---|---|---|
| ETH/USD | 49.0% | 50.1% | -2.0 | 86% of normal | 12,514 |
| Gold (XAU/USD) | 50.5% | 51.1% | -1.9 | 79% of normal | 35,729 |
| EUR/USD | 49.6% | 50.1% | -1.6 | 92% of normal | 36,005 |
| GBP/USD | 49.4% | 49.9% | -1.6 | 88% of normal | 32,382 |
| AUD/USD | 49.6% | 50.1% | -1.4 | 90% of normal | 33,111 |
| GER40 (DAX) | 51.0% | 51.6% | -1.3 | 88% of normal | 15,270 |
Every claim here reduces to a window on the clock or the calendar, so it can simply be checked. We compare the claimed window against the rest of the week on 23 years of hourly data across 19 markets, measuring two separate things the folklore tends to conflate: direction (does the window close higher more often?) via a two-proportion z-test, and movement (is the average move bigger or smaller?). A window can be perfectly ordinary in direction and genuinely quieter in movement — saying which is the entire point.
The bar here is |z| ≥ 2, deliberately more lenient than the |z| ≥ 3 this site applies to its own numbers: when testing someone else's claim, failing to reject it even at a lenient bar is the stronger statement.