+1 sessions
Median return +0.33%Completed observations: 32
- Middle 50%
- -2.51% … +2.00%
- Positive returns
- 53%
Coherent · Sigma Moves
Closed-period price moves, measured against their own history. One engine. Five markets. No forecasts.
Latest closed period
Coherent's latest move against its own history.
COHR Below threshold
-1.12%
-0.21σ
Common move: this size or larger in 78% of observations
975 comparable moves / 1,254 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 +1.04%Completed observations: 32
- Middle 50%
- -5.57% … +6.00%
- Positive returns
- 56%
+30 sessions
Median return +3.42%Completed observations: 32
- Middle 50%
- -7.27% … +25.24%
- Positive returns
- 59%
Every rare move, in context
Instrument: COHR (price return)
| Date | σ | Move | Observed rarity | +1 sessions | +7 sessions | +30 sessions |
|---|---|---|---|---|---|---|
| 2 Jun 2026 | +3.79σ | +17.63% | About once every 126 trading sessions10 comparable moves / 1,255 observations | -2.22% | -14.83% | -35.12% |
| 11 May 2026 | +2.74σ | +13.25% | About once every 52 trading sessions24 comparable moves / 1,255 observations | -1.50% | -5.58% | +3.37% |
| 2 Mar 2026 | +3.29σ | +15.44% | About once every 97 trading sessions13 comparable moves / 1,255 observations | -6.06% | -15.89% | +4.85% |
| 8 Jan 2026 | -2.68σ | -9.64% | About once every 52 trading sessions24 comparable moves / 1,255 observations | +2.84% | +11.73% | +43.74% |
| 6 Nov 2025 | +4.58σ | +18.32% | About once every 209 trading sessions6 comparable moves / 1,255 observations | -3.01% | -12.70% | +16.65% |
| 10 Oct 2025 | -2.88σ | -9.19% | About once every 66 trading sessions19 comparable moves / 1,255 observations | +3.63% | +8.72% | +25.57% |
| 14 Aug 2025 | -7.96σ | -19.61% | 2 times in 5 years2 comparable moves / 1,255 observations | +1.91% | -1.25% | +16.74% |
| 9 Apr 2025 | +2.94σ | +22.67% | About once every 66 trading sessions19 comparable moves / 1,256 observations | -12.06% | -17.32% | +25.13% |
| 3 Apr 2025 | -4.54σ | -20.18% | About once every 209 trading sessions6 comparable moves / 1,256 observations | -6.18% | +4.14% | +45.80% |
| 27 Jan 2025 | -5.58σ | -18.95% | 4 times in 5 years4 comparable moves / 1,257 observations | +1.44% | +10.80% | -18.25% |
| 19 Nov 2024 | +2.62σ | +9.33% | About once every 47 trading sessions27 comparable moves / 1,258 observations | -0.83% | -3.92% | +1.91% |
| 7 Nov 2024 | +3.34σ | +10.08% | About once every 90 trading sessions14 comparable moves / 1,258 observations | +0.52% | -12.88% | -10.76% |
| 2 Aug 2024 | -2.74σ | -10.00% | About once every 48 trading sessions26 comparable moves / 1,258 observations | -4.55% | +13.63% | +27.69% |
| 3 Jun 2024 | +8.90σ | +22.85% | 1 times in 5 years1 comparable moves / 1,259 observations | -6.01% | +0.47% | +8.16% |
| 6 Feb 2024 | +6.82σ | +17.36% | 2 times in 5 years2 comparable moves / 1,258 observations | +6.71% | +4.33% | +3.47% |
| 16 Jan 2024 | +3.51σ | +8.17% | About once every 105 trading sessions12 comparable moves / 1,257 observations | -2.35% | +5.69% | +28.37% |
| 16 Aug 2023 | -9.85σ | -29.87% | Not previously observed in 5 years0 comparable moves / 1,257 observations | +1.43% | +7.34% | -2.61% |
| 21 Jun 2023 | -3.28σ | -15.26% | About once every 74 trading sessions17 comparable moves / 1,257 observations | +4.03% | +8.77% | +0.32% |
| 14 Jun 2023 | +3.29σ | +14.22% | About once every 79 trading sessions16 comparable moves / 1,258 observations | +4.83% | -5.56% | -4.78% |
| 26 May 2023 | +3.73σ | +14.02% | About once every 105 trading sessions12 comparable moves / 1,258 observations | +4.22% | +5.82% | +35.28% |
| 4 May 2023 | -2.76σ | -6.88% | About once every 43 trading sessions29 comparable moves / 1,258 observations | +1.34% | -8.40% | +74.69% |
| 6 Apr 2023 | -4.40σ | -10.11% | About once every 252 trading sessions5 comparable moves / 1,259 observations | +5.15% | +1.58% | -6.94% |
| 18 Aug 2022 | +3.11σ | +6.84% | About once every 58 trading sessions21 comparable moves / 1,226 observations | -1.72% | -11.53% | -38.68% |
| 19 May 2022 | -2.83σ | -7.72% | About once every 39 trading sessions30 comparable moves / 1,164 observations | +0.70% | +6.53% | -17.61% |
| 4 Mar 2022 | -2.66σ | -6.95% | About once every 32 trading sessions35 comparable moves / 1,111 observations | -4.79% | -0.92% | -4.78% |
| 15 Dec 2021 | +4.17σ | +8.70% | About once every 132 trading sessions8 comparable moves / 1,057 observations | -3.53% | -1.45% | -14.82% |
| 7 Dec 2021 | +3.07σ | +5.63% | About once every 53 trading sessions20 comparable moves / 1,051 observations | +1.16% | +2.66% | -3.18% |
| 28 Oct 2021 | +2.63σ | +5.68% | About once every 31 trading sessions33 comparable moves / 1,024 observations | -1.10% | +4.02% | +9.14% |
| 4 Oct 2021 | -5.45σ | -8.32% | 2 times in 4 years2 comparable moves / 1,006 observations | +0.14% | +0.50% | +17.64% |
| 26 Jul 2021 | -2.88σ | -5.59% | About once every 42 trading sessions23 comparable moves / 957 observations | -1.91% | +3.00% | -8.25% |
| 12 Feb 2021 | -3.56σ | -9.70% | About once every 70 trading sessions12 comparable moves / 845 observations | +2.26% | -0.68% | -25.72% |
| 5 Nov 2020 | +7.61σ | +18.51% | Not previously observed in 3 years0 comparable moves / 778 observations | +1.76% | +7.22% | +32.66% |
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.