>
COMMANDS Global: GP Symbol: IBM FA
↑↓ Navigate Enter Open Esc Close ` Toggle

Anomaly Detection

262.06 3.43 (1.33%) 08/24/2026
Amazon.com, Inc. (AMZN)
40
Watch
0204570100
Composite anomaly score
AMZN scores 40/100 — Watch. Nothing has fired in the last 5 sessions — the most recent of the 13 events below is 16 sessions back, and is decaying out of the score. Everything below is recomputed from raw adjusted prices on this request; nothing is read from stored statistics.
262.06Last close
+0.04σvs 20d envelope
13Events in window
0Last 5 sessions
XLYBenchmark
286Bars analysed
24-Aug-2026Through
Shaded band is the rolling 20-session mean ±2σ of the adjusted close, computed ex-ante — each session is judged against the 20 sessions before it, never a window that already contains it. Markers show the sessions a detector fired.
Event log — Liquidity Drop (clear filter)
No anomalies detected in this window for this detector. That is a result, not a gap — the symbol stayed inside its own norms.
How this is scored

Each detector z-scores one series against the symbol's own recent history and fires on the session the threshold is first crossed — a transition, not a state, with a 3-session cooldown, so one three-week volatility regime is one event rather than fifteen identical rows. Every rolling statistic is ex-ante.

DetectorSeries scoredBaselineFires atWeightStatus for AMZN
Price Gap1-day % return20 sessions|z| ≥ 2.51.00active
Volume Surgelog volume (adjusted)20 sessionsz ≥ 2.00.90active
Volatility Spikelog 5-session realized vol, annualized60 sessionsz ≥ 2.01.00active
Options Flowput/call volume, IV30, IV30/IV9060 sessions|z| ≥ 2.00.90unavailableOptions history for this symbol is 6 sessions; the detector needs 20 to form a baseline.
Correlation Break20-session correlation to benchmark120 sessionsz ≤ -2.00.80active
Liquidity Droplog traded value (price × volume)60 sessionsz ≤ -2.50.70active
Model-based8-feature joint vectorup to 500 sessionsboth models agree0.60activeNightly batch, last run 23-Aug-2026.

Severity comes from |z| alone, so the same number means the same thing in every detector: Critical ≥ 4.0σ (base 40), High ≥ 3.0σ (28), Medium ≥ 2.5σ (18), Low below that (10). Confidence scales with how deep the baseline actually was, which is why options events on a thin history are discounted rather than trusted at face value.

The composite is contribution = base × weight × confidence × 0.5^(sessions_ago / 10), summed over events in the last 60 sessions, then squashed with score = 100 × (1 − e^(−sum/60)) so it saturates instead of running away. Bands: Nominal < 20, Watch 20–44, Elevated 45–69, Critical ≥ 70. This symbol's raw sum is 30.35. Engine v1.0.

Known limits — read before trading off this

Liquidity is a tape proxy. KA has no order-book depth, so the Liquidity Drop detector scores traded value (price × volume). Read it as "harder to get size done", not as a measured spread or book thinning.

Options history is shallow. options_iv_history is a forward-only nightly snapshot; for most of the universe the baseline is weeks rather than years, so options events carry low confidence and will strengthen on their own as the snapshot accumulates.

Correlation is US-session only. A same-dated close on a non-US venue is a different trading day, so benchmarking it against SPY or a sector ETF would measure the time zone rather than the decoupling. Non-US symbols simply do not run that detector.

The model-based detector asks a different question. The six univariate detectors are rolling — each session is judged against the 20 to 120 sessions immediately before it, so they fire throughout a window. The model is fitted once over the symbol’s whole stored history and marks the most extreme sessions in it, so a symbol whose violent period was eighteen months ago can legitimately show zero model events in a six-month window. A count of zero here means “nothing in this window ranks among the symbol’s most extreme sessions”, not that the detector failed.

The model-based detector cannot explain itself. The other six each score one series, so every flag decomposes into expected vs actual. IsolationForest and LocalOutlierFactor return a score over the joint vector and nothing decomposable; the drill-down shows the standardised features they saw, which is the nearest honest substitute. It is weighted below the six for that reason, it runs from a nightly batch rather than live, and a flag landing on a day another detector already explained contributes nothing to the score.

Detection is not prediction. A high score says the symbol is behaving unlike itself, not which way it goes next. The detectors have not been validated against a hand-labelled event set, and the score has not been tested for correlation with subsequent realized volatility.

Market News ×
Loading news…