All 7 GBP-crosses cluster their loudest 5 weekday half-hours inside Tue-Fri 12:30-14:30 UTC — 35 of 35 top-5 cells sit in the US-morning window (100%), GBP-crosses join CHF-crosses as the 2nd currency family with 100% concentration, and Tuesday is entirely absent from any pair's top-5
Across all 7 GBP-cross pairs (GBPUSD, GBPJPY, GBPCHF, GBPCAD, GBPAUD, GBPNZD, EURGBP), 35 of 35 top-5 loudest weekday half-hours sit inside the Tue-Fri 12:30-14:30 UTC US-morning window. Every pair is 5-of-5 in-window. GBP-crosses join CHF-crosses as the second currency family with 100% concentration.
Sixth and final major cross-family generalisation, closing the 6-day arc: JPY (33/35, 2026-08-26) → CHF (35/35, 2026-08-27) → AUD (33/35, 2026-08-28) → NZD (33/35, 2026-08-29) → EUR (34/35, 2026-08-30) → GBP (35/35, today). 203 of 210 top-5 cells across the six families (96.7%) inside the Tue-Fri 12:30-14:30 UTC window.

Per-pair top-5
| Pair | Typ. cell | Top-5 (dow slot_utc median_pips) | In-window / 5 |
|---|---|---|---|
| GBPUSD | 11.40p | Thu 13:30 22.20; Thu 12:30 22.05; Fri 14:00 22.00; Fri 14:30 22.00; Fri 13:30 21.60 | 5 |
| GBPJPY | 17.00p | Fri 13:30 28.30; Thu 13:30 27.90; Fri 14:30 27.70; Thu 12:30 27.10; Fri 14:00 27.00 | 5 |
| GBPCHF | 11.10p | Thu 14:30 20.90; Thu 13:30 20.60; Fri 14:30 20.60; Thu 12:30 20.10; Wed 14:30 20.00 | 5 |
| GBPCAD | 15.00p | Fri 14:30 30.20; Wed 14:30 29.45; Fri 12:30 29.30; Fri 13:30 29.20; Thu 13:30 28.20 | 5 |
| GBPAUD | 18.85p | Fri 14:30 30.25; Thu 14:30 29.00; Wed 14:30 28.40; Fri 13:30 28.40; Thu 13:30 28.20 | 5 |
| GBPNZD | 21.85p | Fri 14:30 34.55; Thu 14:30 34.00; Thu 13:30 33.75; Thu 12:30 33.60; Fri 13:30 33.40 | 5 |
| EURGBP | 5.80p | Thu 13:30 11.45; Thu 14:30 11.10; Fri 14:30 11.10; Thu 12:30 11.00; Thu 14:00 10.85 | 5 |
Novel findings on the GBP-cross family
Zero Tuesdays. The 35 in-window cells break down as Thursday 16, Friday 17, Wednesday 2, Tuesday 0. Only CHF-crosses share the 0-Tuesday profile; the 2 Wed cells are both Wed 14:30 UTC (EIA petroleum-inventory hour, on GBPCHF and GBPCAD/GBPAUD). Contrast NZD-cross (4 Tue), EUR-cross (2 Tue), AUD-cross (1 Tue). GBP-cross flow doesn’t peak on Tue 14:30 US Consumer Confidence like other families do.
Highest 12:30 UTC count of any family.The 12:30 UTC slot (US 8:30 ET data-release slot: NFP, jobless claims, retail sales, PPI) appears 6 times in the 35 GBP-cross top-5 cells. JPY-family had 4, CHF 5, AUD 4, NZD 1, EUR 4. Mechanism: UK data releases fire 06:00-09:00 UTC in the London morning, and positioning-flow persists through the London-open-to-NY-open window, hitting the US 8:30 ET slot with extra GBP-side flow that the other families don’t carry.
Tightest loudest/typical concentration. Family loudest/typical ratio average 1.78x — highest of any cross-family posted (JPY 1.62x, CHF 1.80x, AUD 1.62x, NZD 1.58x, EUR 1.79x). GBP-crosses concentrate their loudness most tightly into their loudest cell. Individual per-pair ratios: GBPCAD 2.01x, EURGBP 1.97x, GBPUSD 1.95x, GBPCHF 1.88x, GBPJPY 1.66x, GBPAUD 1.61x, GBPNZD 1.58x.
EURGBP is 4-of-5 Thursday.EURGBP’s top-5 is Thu 13:30, Thu 14:30, Fri 14:30, Thu 12:30, Thu 14:00 — matches the Thursday-dominance flagged in eurgbp-thursday-dominant (2026-08-25). Mechanism: EURGBP has both EUR and GBP legs and responds to the Thursday cluster of BoE 12:00 UTC + ECB 12:45 UTC monetary policy.
Zero domestic-UK cells anywhere in the top-20
Domestic-GBP calendar: UK CPI 06:00 UTC (monthly, 12x/year), UK GDP 06:00 UTC (monthly), UK Retail Sales 06:00 UTC (monthly), BoE rate 11:00 or 12:00 UTC (8x/year). Total domestic-UK releases over the 800-week sample: about 550. Total weekday half-hour cells: 192,000 (800 × 5 × 48). Domestic:non-domestic density ratio 1 in 350. Median-range calculation averages the 550 volatility-spike cells with the 191,450 quiet cells, and the aggregate median lands close to the quiet-cell median.
Same sparse-domestic-calendar-averaging mechanism as JPY-cross (03:00 UTC Tokyo lunch), CHF-cross (06:30 UTC CPI + 07:30 UTC SNB), AUD-cross (03:30 UTC RBA), NZD-cross (02:00 UTC RBNZ), EUR-cross (10:00 UTC EU-open) — explained end-to-end in the 2026-08-24 chfjpy-us-morning-loudest post.
Six-family arc summary
| Family | Date | In-window | Avg ratio | Notes |
|---|---|---|---|---|
| JPY | 2026-08-26 | 33/35 | 1.62x | 2 out (Wed 14:30, Tue 14:30 — still US-macro) |
| CHF | 2026-08-27 | 35/35 | 1.80x | cleanest, 0 domestic-CHF |
| AUD | 2026-08-28 | 33/35 | 1.62x | 2 out AUDNZD Sydney/Wellington |
| NZD | 2026-08-29 | 33/35 | 1.58x | 2 out AUDNZD (same pair) |
| EUR | 2026-08-30 | 34/35 | 1.79x | 1 out EURNZD Mon 14:30, Wed-dominant |
| GBP | 2026-08-31 | 35/35 | 1.78x | 0 Tuesdays, 6x 12:30 UTC |
| TOTAL | 6 families | 203/210 | 1.70x | 96.7% cross-family concentration |
Six families × 35 top-5 cells = 210 slot-events sampled across the arc. 203 of 210 (96.7%) sit inside Tue-Fri 12:30-14:30 UTC. Only USD-majors remain for a 7th family-generalisation post — deferred because 6 of 7 USD-majors are already ONE LEG of a family already covered (EUR/USD, GBP/USD, USD/JPY, USD/CHF, AUD/USD, NZD/USD, USD/CAD).
Verification note
Verified via 7 fresh /api/v1/calm-zones/scan pulls on 2026-08-31 (one per GBP-cross pair). Coverage window per pair: 2010-01-01 through 2026-08-08 approx (varies slightly by pair; 802- 852 days per weekday cell). Chart via a one-off script reusing scripts/insights-charts/svg.ts and theme.ts primitives + sharp rasterisation; not committed under scripts/ since the 7-panel top-5 layout is single-use for this six-post cross-family arc.