+1 sessions
Median return -0.02%Completed observations: 46
- Middle 50%
- -0.61% … +0.72%
- Positive returns
- 50%
Australia 200 (ASX) · Sigma Moves
Closed-period price moves, measured against their own history. One engine. Five markets. No forecasts.
Latest closed period
Australia 200 (ASX)'s latest move against its own history.
AS51 Below threshold
-0.09%
-0.13σ
Common move: this size or larger in 88% of observations
1115 comparable moves / 1,264 observations
What happened afterwards
All history-qualified moves of at least 2.5σ. Results after the event are descriptive statistics, not trading instructions.
+7 sessions
Median return +0.48%Completed observations: 45
- Middle 50%
- -1.13% … +1.74%
- Positive returns
- 58%
+30 sessions
Median return +1.81%Completed observations: 45
- Middle 50%
- -1.27% … +3.54%
- Positive returns
- 69%
Every rare move, in context
Instrument: ^AXJO (price return)
| Date | σ | Move | Observed rarity | +1 sessions | +7 sessions | +30 sessions |
|---|---|---|---|---|---|---|
| 1 Oct 2026 | -3.62σ | -1.99% | 4 times in 5 years4 comparable moves / 1,264 observations | +0.79% | — | — |
| 9 Mar 2026 | -3.16σ | -2.85% | About once every 90 trading sessions14 comparable moves / 1,264 observations | +1.09% | +0.48% | +2.84% |
| 9 Feb 2026 | +2.94σ | +2.33% | About once every 57 trading sessions22 comparable moves / 1,264 observations | -0.50% | +1.06% | -6.13% |
| 6 Feb 2026 | -3.29σ | -2.03% | About once every 140 trading sessions9 comparable moves / 1,264 observations | +2.33% | +2.87% | -3.22% |
| 18 Nov 2025 | -3.24σ | -1.94% | About once every 126 trading sessions10 comparable moves / 1,264 observations | -0.25% | +1.77% | +3.05% |
| 14 Nov 2025 | -2.52σ | -1.36% | About once every 34 trading sessions37 comparable moves / 1,264 observations | +0.02% | -1.13% | +0.96% |
| 3 Sep 2025 | -3.44σ | -1.82% | About once every 181 trading sessions7 comparable moves / 1,264 observations | +1.00% | +1.44% | +2.88% |
| 18 Jul 2025 | +2.52σ | +1.37% | About once every 34 trading sessions37 comparable moves / 1,264 observations | -1.02% | -0.60% | +2.47% |
| 10 Apr 2025 | +2.95σ | +4.54% | About once every 67 trading sessions19 comparable moves / 1,265 observations | -0.82% | +2.74% | +9.05% |
| 7 Apr 2025 | -4.43σ | -4.23% | Not previously observed in 5 years0 comparable moves / 1,265 observations | +2.27% | +5.66% | +13.69% |
| 4 Apr 2025 | -3.12σ | -2.44% | About once every 127 trading sessions10 comparable moves / 1,265 observations | -4.23% | +1.22% | +9.38% |
| 31 Mar 2025 | -2.58σ | -1.74% | About once every 45 trading sessions28 comparable moves / 1,265 observations | +1.04% | -5.97% | +5.79% |
| 7 Mar 2025 | -2.68σ | -1.81% | About once every 49 trading sessions26 comparable moves / 1,265 observations | +0.18% | -1.10% | -1.65% |
| 3 Feb 2025 | -2.64σ | -1.79% | About once every 42 trading sessions30 comparable moves / 1,266 observations | -0.06% | +1.86% | -6.27% |
| 19 Dec 2024 | -3.38σ | -1.70% | About once every 158 trading sessions8 comparable moves / 1,266 observations | -1.24% | +0.40% | +3.04% |
| 22 Oct 2024 | -2.70σ | -1.66% | About once every 47 trading sessions27 comparable moves / 1,266 observations | +0.13% | -0.56% | +3.53% |
| 5 Aug 2024 | -4.10σ | -3.70% | 4 times in 5 years4 comparable moves / 1,264 observations | +0.41% | +2.63% | +6.17% |
| 2 Aug 2024 | -2.74σ | -2.11% | About once every 45 trading sessions28 comparable moves / 1,264 observations | -3.70% | -1.47% | +1.97% |
| 16 Apr 2024 | -3.10σ | -1.81% | About once every 74 trading sessions17 comparable moves / 1,262 observations | -0.09% | -0.48% | +0.70% |
| 11 Mar 2024 | -3.24σ | -1.82% | About once every 97 trading sessions13 comparable moves / 1,264 observations | +0.11% | -0.11% | -0.28% |
| 14 Dec 2023 | +2.57σ | +1.65% | About once every 39 trading sessions32 comparable moves / 1,263 observations | +0.88% | +2.48% | +4.10% |
| 6 Dec 2023 | +2.65σ | +1.65% | About once every 44 trading sessions29 comparable moves / 1,263 observations | -0.07% | +3.68% | +4.15% |
| 22 Jun 2023 | -2.52σ | -1.63% | About once every 33 trading sessions38 comparable moves / 1,263 observations | -1.34% | +0.70% | +1.61% |
| 31 May 2023 | -3.01σ | -1.64% | About once every 55 trading sessions23 comparable moves / 1,263 observations | +0.27% | +0.44% | +2.19% |
| 10 Mar 2023 | -4.15σ | -2.28% | 3 times in 5 years3 comparable moves / 1,263 observations | -0.50% | -2.65% | +2.40% |
| 11 Nov 2022 | +2.58σ | +2.79% | About once every 36 trading sessions35 comparable moves / 1,263 observations | -0.16% | +0.33% | -0.70% |
| 4 Oct 2022 | +3.21σ | +3.75% | About once every 74 trading sessions17 comparable moves / 1,262 observations | +1.74% | -0.85% | +6.60% |
| 14 Sep 2022 | -2.75σ | -2.58% | About once every 42 trading sessions30 comparable moves / 1,249 observations | +0.21% | -5.26% | +0.24% |
| 1 Sep 2022 | -2.50σ | -2.02% | About once every 31 trading sessions40 comparable moves / 1,240 observations | -0.25% | +1.74% | -1.27% |
| 29 Aug 2022 | -2.69σ | -1.95% | About once every 40 trading sessions31 comparable moves / 1,237 observations | +0.47% | -3.39% | -4.60% |
| 14 Jun 2022 | -3.52σ | -3.55% | About once every 108 trading sessions11 comparable moves / 1,183 observations | -1.27% | -2.36% | +1.81% |
| 6 May 2022 | -2.50σ | -2.16% | About once every 31 trading sessions37 comparable moves / 1,157 observations | -1.18% | -1.29% | -10.72% |
| 26 Apr 2022 | -2.92σ | -2.08% | About once every 44 trading sessions26 comparable moves / 1,149 observations | -0.78% | +0.64% | -3.04% |
| 22 Apr 2022 | -2.55σ | -1.57% | About once every 37 trading sessions31 comparable moves / 1,148 observations | -2.08% | -2.26% | -3.57% |
| 24 Feb 2022 | -3.20σ | -2.99% | About once every 69 trading sessions16 comparable moves / 1,109 observations | +0.10% | +0.69% | +6.47% |
| 25 Jan 2022 | -2.54σ | -2.49% | About once every 35 trading sessions31 comparable moves / 1,088 observations | -1.77% | +2.28% | +1.31% |
| 21 Jan 2022 | -2.62σ | -2.27% | About once every 39 trading sessions28 comparable moves / 1,086 observations | -0.51% | -1.23% | -1.91% |
| 6 Jan 2022 | -3.70σ | -2.74% | About once every 179 trading sessions6 comparable moves / 1,075 observations | +1.29% | +0.80% | -1.86% |
| 4 Jan 2022 | +3.08σ | +1.95% | About once every 67 trading sessions16 comparable moves / 1,073 observations | -0.32% | -1.52% | -4.02% |
| 26 Nov 2021 | -2.97σ | -1.73% | About once every 48 trading sessions22 comparable moves / 1,049 observations | -0.54% | +0.48% | +2.19% |
| 20 Sep 2021 | -3.57σ | -2.10% | About once every 111 trading sessions9 comparable moves / 1,000 observations | +0.35% | -0.71% | +1.69% |
| 9 Sep 2021 | -4.30σ | -1.90% | 3 times in 4 years3 comparable moves / 993 observations | +0.50% | -1.65% | +0.62% |
| 21 Jun 2021 | -3.00σ | -1.81% | About once every 52 trading sessions18 comparable moves / 935 observations | +1.48% | +1.07% | +3.54% |
| 19 May 2021 | -3.02σ | -1.90% | About once every 57 trading sessions16 comparable moves / 913 observations | +1.27% | +3.57% | +4.82% |
| 26 Feb 2021 | -2.88σ | -2.35% | About once every 48 trading sessions18 comparable moves / 857 observations | +1.74% | +1.47% | +4.55% |
| 28 Jan 2021 | -2.54σ | -1.93% | About once every 40 trading sessions21 comparable moves / 836 observations | -0.64% | +3.47% | +0.97% |
The number has a method behind it
Sigma measures the size of a log return relative to volatility estimated before the period. Rarity is counted from actual historical standardized moves, not inferred from a normal distribution.
σt = ln(Ct / Ct−1) / vtvt ← t−1, t−2, …
Volatility adapts to the market regime with EWMA (λ = 0.94 for daily and weekly observations). Current-period returns are excluded. Each historical σ uses its own prior volatility.
Both directions count toward rarity. Reference history spans up to five years. A period with no prior exceedances is labelled unprecedented in the observed sample; it is never given an invented recurrence interval.
Stock observations use split-adjusted price returns, without dividend reinvestment. Commodities are explicitly labelled ETF price proxies; they do not represent spot commodity prices.
Questions behind the sigma
What does a 3σ move mean?
The period log return is three times the volatility estimated from earlier periods. Sigma is signed: negative for declines and positive for rises.
Why not calculate rarity from a normal distribution?
Market returns have heavy tails and changing volatility. We count actual past absolute sigma exceedances for the same instrument and period.
Does “once every 200 days” predict the next event?
No. It is the number of historical observed periods divided by comparable moves. Events can cluster and the market regime can change.
How much history is required?
At least three years of valid standardized observations, after a one-year volatility warm-up. This normally requires approximately four years of source history.
Are all instruments directly comparable?
The engine is shared, but each instrument has its own prices, calendar, volatility and reference sample. Commodity cards use explicitly labelled ETF proxies.
What happens on quiet days?
The page shows the largest covered standardized move, the complete rarity scale and recent records. Missing data is reported separately from market calm.
For information only. Historical observations are not investment advice and do not predict future moves. A rare move can be followed by another rare move.