Percentile Stretch Bands [AGPro Series]Percentile Stretch Bands
🔹 OVERVIEW
Percentile Stretch Bands is an empirical, distribution-free overextension map. Instead of plotting standard deviation envelopes that assume a normal distribution of price behavior, this indicator samples the actual historical distance between price and a chosen reference (EMA, VWAP, or Anchored VWAP) and draws context-specific Stretch and Extreme bands directly from the empirical percentile distribution. The result is a visual reference of how stretched price is relative to its own historical behavior, adapted to the asset and timeframe being viewed.
🔹 UNIQUE EDGE
Most "stretch" or "volatility band" tools on the platform rely on parametric assumptions — standard deviation multipliers, ATR multiples, or fixed percentage offsets. These approaches collapse when the underlying return distribution is skewed, fat-tailed, or regime-dependent, which is the rule rather than the exception across crypto and FX assets.
Percentile Stretch Bands takes a different path:
• Distribution-free: bands are drawn from the actual empirical percentile of price-to-reference distance, not from a Gaussian assumption.
• Side-specific sampling: upper and lower distances are collected into separate samples, so asymmetric behavior (trending markets, one-sided regimes) is preserved rather than averaged away.
• Regime-aware rendering: when Focus Active Side is enabled, each bar displays only the side relevant to price position, producing a clean single-story chart without visual competition.
• Readiness gating: bands appear only once a minimum number of observations is reached on the active side, with the status panel clearly indicating the collection stage.
🔹 METHODOLOGY
For every bar in the configured lookback window, the signed percent distance between close and the selected reference is computed and partitioned into two historical samples: positive distances (upper extensions) and negative distances in absolute terms (lower extensions).
Each sample is sorted and two percentile cut-offs are extracted independently:
• Stretch percentile (default 80) — the threshold beyond which a distance is considered materially extended.
• Extreme percentile (default 95) — the threshold beyond which a distance is statistically rare within the chosen lookback.
These cut-offs are then translated from percent-distance back into absolute price bands around the active reference, producing four levels: Upper Stretch, Upper Extreme, Lower Stretch, Lower Extreme. The current distance is also ranked against its side's sample and displayed as an ordinal percentile (for example, "Upper P87") in the status panel.
🔹 SIGNALS AND ALERTS
The indicator is a visual overextension map and does not generate directional trade signals. Four alert conditions are exposed for users who want to be notified of boundary events:
• Upper Stretch Cross — close crosses above the Upper Stretch band.
• Upper Extreme Cross — close crosses above the Upper Extreme band.
• Lower Stretch Cross — close crosses below the Lower Stretch band.
• Lower Extreme Cross — close crosses below the Lower Extreme band.
These alerts mark entries into statistically extended zones relative to the empirical sample. They are contextual flags, not trade recommendations.
🔹 KEY INPUTS
Reference
• Reference Mode — EMA, VWAP, or Anchored VWAP baseline
• EMA Length — smoothing length for the EMA reference
• AVWAP Anchor Time — starting timestamp for Anchored VWAP
Statistics
• Lookback — bars used to build the empirical distribution (default 500)
• Minimum Side Sample — observations required before bands appear
• Stretch Percentile — primary extension threshold (default 80)
• Extreme Percentile — rare-extension threshold (default 95)
Display
• Focus Active Side — regime-aware single-story rendering
• Show Active Stretch Zone Box — right-side zone anchor on the active side
• Zone Forward Projection — forward visibility of the active zone
• Band Color Profile — Soft, Premium, or Bold
• Panel Text Size and Label Text Size — Small, Normal, or Large
Level Tags
• Show Level Tags, Show Reference Tag, Tag Mode, Tag Offset Bars
🔹 HOW TO USE
1. Select a reference that fits the asset and timeframe. EMA is a robust default across all instruments. VWAP is suited to intraday equities and futures. Anchored VWAP is used when a specific event origin (earnings, news, structural low) is relevant.
2. Let the status panel reach the "Ready" state. The panel reports active samples and readiness — bands are intentionally withheld until the side-specific sample is sufficient.
3. Read the current percentile rank in the Zone cell. Values near the center indicate price trading close to the reference; values approaching P95 or above indicate the sample's rare extensions.
4. Treat Stretch and Extreme bands as context, not as triggers. A move into the Extreme zone reflects a statistically rare extension on the chosen sample, not a directional signal.
5. Combine with structural tools — trend context, market structure, higher-timeframe bias — before any discretionary decision.
🔹 LIMITATIONS AND TRANSPARENCY
• The indicator is descriptive, not predictive. Percentile bands describe past behavior within the lookback window; they do not forecast future price action.
• Regime shifts can temporarily invalidate historical bands. A sudden volatility expansion will push price beyond extreme levels while the sample re-stabilizes.
• Empirical percentiles require sufficient observations. On very new symbols or short lookbacks, the "Collecting" state is the correct and expected behavior.
• Anchored VWAP mode depends on a meaningful anchor choice. A poorly chosen anchor produces a reference line without structural relevance.
• The active stretch zone box is a visual anchor for screenshots and review, not a projection of future levels.
🔹 RISK DISCLOSURE
This script is a visual analytics tool and is not a strategy, signal service, or financial advice. It does not place orders, manage positions, or recommend directional exposure. Trading involves risk of loss. Users are responsible for their own analysis, risk management, and trading decisions.
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