AU Trimmed Mean CPI q/q on AUDCHF: all 5 big-miss prints sent AUDCHF DOWN AND all 4 big-beat prints sent it UP — DOUBLE tail unanimity that HOLDS at 1m, 5m, 15m, AND 30m. First-ever AUDCHF anchor for the RBA's preferred inflation gauge, second post in the Trimmed Mean CPI series.
67 non-contaminated Australia Trimmed Mean CPI q/q releases (2010-01-27 through 2026-06-24) on AUDCHF. At 1m, 5m, 15m, AND 30m: all 5 big-miss prints sent AUDCHF DOWN (100%) AND all 4 big-beat prints sent it UP (100%) — quadruple-window DOUBLE tail unanimity. 15m median walk -28.0 / -19.4 / +0.3 / +19.0 / +11.1 pips with perfectly monotonic pct-up walk 0 / 17 / 52 / 80 / 100%.
First-ever AUDCHF × Trimmed Mean CPI News Impact anchor, and the second post in the Trimmed Mean CPI series after aud-trimmed-mean-cpi-audusd (2026-08-04). AUDUSD established the initial DOUBLE-tail-unanimity finding at 15m; today’s AUDCHF post extends it to a 4-window persistence (1m through 30m all at 100%+100%).

The full 5-bucket table at 15 minutes
| Bucket | n | Median | Pct-up | Interpretation |
|---|---|---|---|---|
| big_miss | 5 | -28.0p | 0.0% | 5 of 5 DOWN (unanimity) |
| small_miss | 18 | -19.4p | 16.7% | AUD weak → AUDCHF down (15 of 18) |
| in_line | 25 | +0.3p | 52.0% | coin-flip |
| small_beat | 15 | +19.0p | 80.0% | AUD strong → AUDCHF up (12 of 15) |
| big_beat | 4 | +11.1p | 100.0% | 4 of 4 UP (unanimity) |
The pct-up column is perfectly monotonic 0 / 17 / 52 / 80 / 100% across all 5 buckets — a rare pattern that survives to n=67 only when the underlying event cleanly repriced by the market on every extreme surprise. Note the small_beat vs big_beat MEDIAN-magnitude inversion (+19.0p vs +11.1p) — same bucket-boundary artefact as the AUDUSD sibling post, driven by 2020-04-29 (COVID-era z=+4.42 with only +8.7p, because AUD was in a broader risk-off leg dampening a nominally strong signal). Pct-up stays 100% because all 4 prints ARE up; the MAGNITUDE is what’s subdued.
Quadruple-window DOUBLE tail unanimity
| Window | big_miss med | big_miss pct_up | big_beat med | big_beat pct_up |
|---|---|---|---|---|
| 1m | -24.0p | 0.0% (0/5) | +10.1p | 100.0% (4/4) |
| 5m | -32.0p | 0.0% (0/5) | +9.6p | 100.0% (4/4) |
| 15m | -28.0p | 0.0% (0/5) | +11.1p | 100.0% (4/4) |
| 30m | -28.0p | 0.0% (0/5) | +6.5p | 100.0% (4/4) |
| 1h | -31.0p | 20.0% (1/5) | +7.9p | 100.0% (4/4) |
| 4h | -29.0p | 0.0% (0/5) | +13.7p | 75.0% (3/4) |
Four consecutive windows (1m, 5m, 15m, 30m) show 100% + 100% double unanimity — 5 of 5 big-miss prints DOWN and 4 of 4 big-beat prints UP on the same print membership. Under an independent-coin- flip null the joint probability is (1/2)⁵ × (1/2)⁴ = 1/512 = 0.20% at any single window; the quadruple-window replication adds evidence but the correct multiplier is not (1/512)⁴ because adjacent windows are highly correlated (adjacent windows typically share 80-90% of directional signal). At 1h the miss side softens (2020-07-29 COVID-period print flips positive temporarily); at 4h it flips BACK to 100% down. Beat side holds 100% through 1h; at 4h 2022-10-26 (z=+1.91 near-boundary) rotates to flat, giving 75%.
The 5 big-miss and 4 big-beat prints, sorted by date
| Bucket | Release date | surprise_z | 15m pips | Context |
|---|---|---|---|---|
| big_miss | 2011-01-25 | -2.65 | -28.0 | Stevens era, GFC recovery |
| big_miss | 2011-10-26 | -1.67 | -53.0 | boundary z, Q3 2011 sluggish |
| big_miss | 2016-04-27 | -1.83 | -85.9 | loudest single tail; RBA cut expected |
| big_miss | 2020-07-29 | -2.52 | -5.8 | COVID Q2, RBA QE ongoing |
| big_miss | 2021-04-28 | -2.10 | -20.0 | Lowe era, YCC-tapering week |
| big_beat | 2020-04-29 | +4.42 | +8.7 | loudest z; COVID-Q1 shock reading |
| big_beat | 2021-10-27 | +1.79 | +13.5 | hiking-regime onset |
| big_beat | 2022-01-25 | +2.35 | +21.0 | biggest post-COVID beat magnitude |
| big_beat | 2022-10-26 | +1.91 | +0.7 | near-boundary; flat but positive |
The 4 big-beat prints all sit in the post-COVID period (2020-04 onwards) — because the RBA target-rate regime shifted decisively after 2020 with the RBA hiking bias emerging; Trimmed Mean prints during 2010-2019 were mostly clustered near-2% target with fewer strong upside surprises. This means the beat-side unanimity captures a policy-regime-shift transmission (RBA hiking bias, market anticipates further hikes on beats), not a mean-reverting flow story. The 5 big-miss prints span 3 different governors (Stevens, Lowe pre-COVID, Lowe post-COVID) and cover both easing-regime and pre-hiking-regime periods.
Why the persistence holds so cleanly on AUDCHF
Two mechanisms make AUDCHF the persistence winner among AUD-quote pairs on this event:
1. Low counter-flow.CHF is the second-quietest weekday-flow currency after JPY (per BIS Triennial Central Bank Survey 2022). The SNB rarely surprises and there’s no daily CHF-side macro that would compete with a Wednesday AUD Trimmed Mean release. An AUD-side directional impulse transmits through AUDCHF with minimal counter-flow resistance.
2. Small typical range → larger signal-to-noise on any tail move.AUDCHF’s typical weekday cell is ~10 pips (see AUD-crosses US-morning family chart). So a 20-30 pip directional move at 15m is 2-3× the typical range — big enough to persist through 30m against a thin baseline. AUDUSD’s typical cell is ~18 pips, so the same absolute move is a smaller signal ratio.
Trimmed Mean CPI is the RBA-preferred inflation gauge
The RBA’s primary underlying-inflation measure is the Trimmed Mean, not headline CPI. RBA policy decisions are made primarily off the Trimmed Mean trajectory (see the RBA’s statistical release "Measures of Consumer Price Inflation"), which means Trimmed Mean surprises carry more rate-decision-implication signal per unit surprise than headline CPI does. This is why the DOUBLE tail unanimity is stronger on Trimmed Mean than on headline AUD CPI y/y (which we covered separately and does not show the same clean directional walk). The event exclusive: quarterly, released alongside headline CPI, with actual/consensus/previous all published simultaneously.
Verification note
All numbers verified against live /api/v1/news-impact/stats and /api/v1/news-impact/releases on 2026-09-03 across all 6 windows. Chart generated via the standard pnpm insights:chart CLI. Sample: 67 non-contaminated Australia Trimmed Mean CPI q/q releases 2010-01-27 through 2026-06-24. First-ever AUDCHF × Trimmed Mean CPI News Impact anchor. Big-miss n=5 and big-beat n=4 are FAR below the MIN_N=30 chart threshold and drawn faint; treat this as a small-sample tail-unanimity finding, not a wide-sample effect-size claim. The coin-flip null probability of the 5-and-4-of-4 double unanimity is 1/512 = 0.20% at any single window.