UK Core CPI on GBPCAD: 13 of 15 big-miss prints sent GBPCAD down at 15m (86.7%), 13 of 15 big-beat prints sent it up (86.7%) — and at 5 minutes the big-beat bucket is 15 of 15 UP (100%). First-ever GBPCAD × UK Core CPI anchor, fifth cross-family leg with 5m unanimity.
198 non-contaminated UK Core CPI y/y releases (2010-01-19 through 2026-06-17) on GBPCAD. At 5 minutes: 15 of 15 big-beat prints sent GBPCAD UP (100% unanimous), coin-flip null p = 0.003%. At 15 minutes: 13/15 big-beat up (86.7%), 13/15 big-miss down (86.7%). Median walk -18.9 / -13.6 / +0.5 / +6.0 / +20.0p — perfectly monotonic on both median AND pct-up.
First-ever GBPCAD × UK Core CPI News Impact anchor, and the fifth leg of the UK Core CPI cross-family after GBPUSD (2026-08-12), EURGBP (2026-08-20), GBPNZD (2026-08-27), and GBPAUD (2026-08-29). All 5 pairs post 86.7-93.3% big-beat up-rate at 15m; GBPCAD is distinguished by 15/15 up at 5m.

The full 5-bucket table at 15 minutes
| Bucket | n | Median | Pct-up | Interpretation |
|---|---|---|---|---|
| big_miss | 15 | -18.9p | 13.3% | GBP very weak → GBPCAD down (13 of 15) |
| small_miss | 53 | -13.6p | 28.3% | GBP weak → GBPCAD down (38 of 53) |
| in_line | 62 | +0.5p | 51.6% | coin-flip |
| small_beat | 53 | +6.0p | 71.7% | GBP strong → GBPCAD up (38 of 53) |
| big_beat | 15 | +20.0p | 86.7% | GBP very strong → GBPCAD up (13 of 15) |
Median walk -18.9 / -13.6 / +0.5 / +6.0 / +20.0 — perfectly monotonic. Pct-up walk 13.3 / 28.3 / 51.6 / 71.7 / 86.7% — perfectly monotonic.
The 5-minute 15-of-15 big-beat unanimity
Every one of the n=15 big-beat prints since 2010-01-19 sent GBPCAD UP at 5 minutes. Under a coin-flip null of P(up) = 0.5, probability = 1/215 = 0.003% — even under the observed 15m up-rate of 86.7%, 0.86715 = 11.5%, so the 5-minute tail is meaningfully stronger than the 15m one. Below, all 15 prints, sorted by date, with the 5m move in pips.
| Release date | surprise_z | 5m pips | 15m pips | 15m dir |
|---|---|---|---|---|
| 2010-01-19 | +2.59 | +35.0 | +20.0 | ↑ |
| 2010-07-13 | +2.18 | +17.0 | +22.0 | ↑ |
| 2012-08-14 | +1.94 | +15.6 | +10.9 | ↑ |
| 2012-11-13 | +3.51 | +17.7 | +0.9 | ↑ |
| 2014-07-15 | +1.68 | +73.5 | +80.8 | ↑ |
| 2015-08-18 | +3.16 | +83.3 | +105.9 | ↑ |
| 2017-03-21 | +1.92 | +44.1 | +45.8 | ↑ |
| 2017-06-13 | +1.99 | +7.2 | -14.2 | ↓ |
| 2018-09-19 | +2.58 | +61.2 | +56.4 | ↑ |
| 2020-08-19 | +3.08 | +9.3 | +12.7 | ↑ |
| 2021-06-16 | +1.95 | +13.4 | +8.8 | ↑ |
| 2022-04-13 | +1.98 | +11.7 | +13.1 | ↑ |
| 2022-08-17 | +1.54 | +1.6 | -4.1 | ↓ |
| 2023-03-22 | +2.32 | +22.2 | +24.0 | ↑ |
| 2023-05-24 | +2.59 | +28.3 | +27.2 | ↑ |
Two of the 15 flipped negative at 15 minutes: 2017-06-13 (UK hung-parliament week 2017-06-08 election, GBP-idiosyncratic-selling dominated the CPI signal) and 2022-08-17 (boundary z=+1.54, GBP-crash-week during Truss campaign). Both were positive at 5 minutes. At 5m the pattern holds without exception.
Beat-side persistence through 4 hours
| Window | big_miss med | big_miss pct_up | big_beat med | big_beat pct_up |
|---|---|---|---|---|
| 1m | -19.1p | 13.3% | +16.3p | 93.3% |
| 5m | -14.9p | 13.3% | +17.7p | 100.0% |
| 15m | -18.9p | 13.3% | +20.0p | 86.7% |
| 30m | -10.9p | 20.0% | +24.5p | 86.7% |
| 1h | -12.8p | 40.0% | +24.6p | 86.7% |
| 4h | -30.75p | 33.3% | +22.45p | 78.6% |
The 5-minute row is the double-tail highlight: 15/15 big-beat up (100%) with median +17.7p. The beat-side median AMPLIFIES to +24.5p at 30m, holds +24.6p at 1h, and only softens to +22.45p at 4h. The pct-up stays at 86.7% at 15m/30m/1h. The miss side is less stationary: median dips at 30m and 1h (-10.9p, -12.8p) then deepens back to -30.75p at 4h with pct_up 33.3%. The beat-side signal is both larger and more time-stationary than the miss-side signal on this event × pair.
Fifth leg of the UK Core CPI cross-family
| Pair | Post date | 15m big-beat pct_up | 15m big-miss pct_down | Unanimity window |
|---|---|---|---|---|
| GBPUSD | 2026-08-12 | 86.7% | 86.7% | — |
| EURGBP | 2026-08-20 | 86.7% down (mirror) | 86.7% up (mirror) | — |
| GBPNZD | 2026-08-27 | 86.7% | 93.3% | 5m AND 1h (double) |
| GBPAUD | 2026-08-29 | 93.3% | 86.7% | 5m AND 30m (double) |
| GBPCAD | 2026-09-01 | 86.7% | 86.7% | 5m only (single) |
Every leg of the family posts 86.7-93.3% big-beat up at 15 minutes on the same 15-of-15 print membership. GBPCAD extends the family from 4 to 5 pairs, and gives it a THIRD pair with 5-minute tail unanimity (after GBPNZD and GBPAUD, which were 15/15 up at TWO windows). Remaining GBP-crosses for future coverage: GBPJPY and GBPCHF.
Verification note
All numbers verified against live /api/v1/news-impact/stats and /api/v1/news-impact/releases on 2026-09-01 across all 6 windows. Chart generated via the standard pnpm insights:chartCLI. Sample: 198 non-contaminated UK Core CPI y/y releases 2010-01-19 through 2026-06-17 (last release June 2026 print). First-ever GBPCAD × UK Core CPI News Impact anchor. Big-miss and big-beat n=15 are below the MIN_N=30 chart threshold and drawn faint; the 5m 15/15 unanimity clears p < 0.001 under coin-flip null even at n=15.