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PepsiCo · Sigma Moves

Closed-period price moves, measured against their own history. One engine. Five markets. No forecasts.

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Latest closed period

PepsiCo's latest move against its own history.

26 May 2026 · Daily
PEP Rare -3.25% -2.72σ About once every 38 trading sessions 33 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.

+1 sessions

Median return +0.28%

Completed observations: 47

Middle 50%
-0.83% … +0.95%
Positive returns
55%

+7 sessions

Median return +0.61%

Completed observations: 47

Middle 50%
-1.03% … +2.02%
Positive returns
55%

+30 sessions

Median return +0.96%

Completed observations: 47

Middle 50%
-4.46% … +3.36%
Positive returns
51%

Every rare move, in context

Instrument: PEP (price return)

DateσMoveObserved rarity+1 sessions+7 sessions+30 sessions
26 May 2026 -2.72σ -3.25% About once every 38 trading sessions33 comparable moves / 1,254 observations +1.41% -2.42% -5.37%
11 May 2026 -3.01σ -3.37% About once every 57 trading sessions22 comparable moves / 1,255 observations +1.63% -0.08% -4.78%
3 Feb 2026 +3.73σ +4.93% About once every 157 trading sessions8 comparable moves / 1,255 observations +2.04% +2.67% -5.72%
30 Jan 2026 +3.07σ +3.32% About once every 66 trading sessions19 comparable moves / 1,255 observations +1.02% +8.68% +2.66%
10 Dec 2025 +3.59σ +3.50% About once every 126 trading sessions10 comparable moves / 1,255 observations -0.44% -1.03% -2.56%
9 Oct 2025 +3.63σ +4.23% About once every 139 trading sessions9 comparable moves / 1,255 observations +3.71% +6.17% +0.96%
8 Sep 2025 -2.56σ -3.20% About once every 33 trading sessions38 comparable moves / 1,255 observations +0.98% -0.34% +8.42%
17 Jul 2025 +6.26σ +7.45% Not previously observed in 5 years0 comparable moves / 1,255 observations -1.51% -2.66% +1.06%
24 Apr 2025 -3.01σ -4.89% About once every 60 trading sessions21 comparable moves / 1,256 observations -1.43% -2.45% -3.90%
4 Apr 2025 -2.52σ -3.14% About once every 32 trading sessions39 comparable moves / 1,256 observations -2.33% -2.57% -10.11%
4 Feb 2025 -3.44σ -4.51% About once every 79 trading sessions16 comparable moves / 1,257 observations +1.51% +0.76% +3.22%
27 Jan 2025 +3.48σ +3.68% About once every 84 trading sessions15 comparable moves / 1,257 observations -2.82% -5.79% -1.47%
10 Jan 2025 -2.52σ -2.66% About once every 27 trading sessions46 comparable moves / 1,257 observations +1.30% +3.82% +9.66%
15 Nov 2024 -5.27σ -3.95% 1 times in 5 years1 comparable moves / 1,258 observations -0.18% +2.23% -4.14%
3 Sep 2024 +3.11σ +2.70% About once every 74 trading sessions17 comparable moves / 1,258 observations +0.55% -0.16% -0.92%
17 Jul 2024 +3.05σ +3.11% About once every 66 trading sessions19 comparable moves / 1,258 observations +0.28% +1.68% +2.37%
10 Jun 2024 -2.68σ -3.01% About once every 31 trading sessions40 comparable moves / 1,259 observations -0.50% +0.47% +1.37%
28 May 2024 -2.51σ -2.59% About once every 26 trading sessions48 comparable moves / 1,259 observations -1.29% -0.10% -5.44%
24 Apr 2024 +2.96σ +3.62% About once every 57 trading sessions22 comparable moves / 1,259 observations -0.41% -0.71% -2.37%
23 Apr 2024 -3.09σ -2.97% About once every 74 trading sessions17 comparable moves / 1,259 observations +3.62% +2.47% +1.33%

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.