OPEN-SOURCE SCRIPT
Updated Fragility-Weighted Liquidity Map Kyle Amihud Roll
Fragility-Weighted Liquidity Map — Kyle · Amihud · Roll
What it is
A move of the same size means opposite things depending on the book beneath it. Into a thin book, a move is mostly price impact — mechanical, fragile, prone to snap back. Into a deep book, the same move took real participation and is more likely informed. This tool estimates how impact-driven the tape is right now from three classic microstructure measures, fuses them into one fragility read, and tints recent liquidity levels by it. It scales conviction and risk — it never picks a direction.
The three measures (all from OHLCV, peer-reviewed)
Kyle's lambda (Kyle 1985) — price impact per unit of signed volume: |price change over a window| ÷ |Σ sign(Δclose)·volume|. High λ = each unit of flow moves price a lot = thin, impactable.
Amihud illiquidity (Amihud 2002) — the average of |return| ÷ dollar-volume. High = small volume moves price a lot. (Empirically ~0.8 correlated with Kyle, so the two are blended, not double-counted.)
Roll implied spread (Roll 1984) — the effective spread implied by the bid-ask bounce: c = 2·√(−Cov(Δp, Δp₋₁)) when that covariance is negative. When it is positive — common in trends — the Roll model does not apply, so the estimate is shown as not measurable here rather than forced to a number. That honesty is deliberate.
Fusion → fragility
Each measure is ranked against its own recent history (a percentile), so the read self-tunes to the symbol and timeframe. The fragility index is the weighted blend of whichever measures are currently available (Roll drops out in trends, and the blend adapts). High fragility = impact-driven, reversible tape; low = deep, informed. A plain-language read suggests trusting breakouts less and fades more when fragility is high — as context, not a signal.
The map
Bars that trade unusually large volume leave a horizontal liquidity level where size changed hands. Each level is tinted by the fragility state at the moment it formed: warm = it printed in a thin/impact-driven tape (a weaker level, more likely to be swept); cool = it printed in a deep/informed tape (sturdier). So the map shows not just where liquidity sits but how trustworthy each pocket is.
How to use it
Add to any liquid symbol/timeframe; defaults suit index futures — change the price/volume sources for other markets.
Glance at the fragility lane — the thin strip at the pane bottom: red = thin/fragile, green = deep/solid, gray = normal. Risk-semantic colors (danger/safe), never direction. That strip alone answers "how careful should I be" for a non-technical user.
States are dwell-filtered (standard anti-chattering): a new THIN/DEEP/NORMAL is announced only after surviving a set number of bars, so the read doesn't flip-flop. STABILITY shows how settled it is; PENDING shows a forming state with a countdown. The cost is a few bars of lag — stated and adjustable.
The HTF STACK row shows the raw fragility state on three higher timeframes derived as multiples of the chart (defaults 3×, 5×, 15× — a 5m chart reads 15m/25m/75m automatically). ✓ green = all timeframes agree on the same actionable state; ⚠ amber = a higher timeframe reads the opposite state.
Read the dashboard: DEEP / NORMAL / THIN, the three measures' ranks, and a suggested size factor. As it turns THIN, treat moves as more reversible: size down, favour fades over breakout-chasing.
Use the rails as liquidity references coloured by trust — a warm rail formed in fragile conditions; a cool rail in solid ones.
Pairs with Order-Flow Criticality: that tool asks whether flow is self-exciting (endogenous); this asks whether the book is thin (impactable). Both elevated together is the genuinely fragile state.
What makes it original
Retail liquidity tools draw where volume traded. This one weights each level and the whole tape by how impactable it is, using three peer-reviewed microstructure estimators computed from bar data, self-calibrated, and — crucially — honest about when the Roll model doesn't apply. Reframing a liquidity map from "where is liquidity" to "how fragile is liquidity" is the contribution.
Concept credits
Price impact of order flow (lambda) — A. S. Kyle (1985). Illiquidity ratio — Y. Amihud (2002). Implied effective spread from serial covariance — R. Roll (1984). Square-root impact refinement — J. Hasbrouck. Fragility framing — general market-microstructure literature. Implementation and charting design are the author's own.
Important disclaimer
Research and education only. Not financial advice, not a signal service, not a guarantee of future results. These are proxies estimated from bar data, not order-book truth, and they do not predict direction. Validate independently and manage your own risk.
What it is
A move of the same size means opposite things depending on the book beneath it. Into a thin book, a move is mostly price impact — mechanical, fragile, prone to snap back. Into a deep book, the same move took real participation and is more likely informed. This tool estimates how impact-driven the tape is right now from three classic microstructure measures, fuses them into one fragility read, and tints recent liquidity levels by it. It scales conviction and risk — it never picks a direction.
The three measures (all from OHLCV, peer-reviewed)
Kyle's lambda (Kyle 1985) — price impact per unit of signed volume: |price change over a window| ÷ |Σ sign(Δclose)·volume|. High λ = each unit of flow moves price a lot = thin, impactable.
Amihud illiquidity (Amihud 2002) — the average of |return| ÷ dollar-volume. High = small volume moves price a lot. (Empirically ~0.8 correlated with Kyle, so the two are blended, not double-counted.)
Roll implied spread (Roll 1984) — the effective spread implied by the bid-ask bounce: c = 2·√(−Cov(Δp, Δp₋₁)) when that covariance is negative. When it is positive — common in trends — the Roll model does not apply, so the estimate is shown as not measurable here rather than forced to a number. That honesty is deliberate.
Fusion → fragility
Each measure is ranked against its own recent history (a percentile), so the read self-tunes to the symbol and timeframe. The fragility index is the weighted blend of whichever measures are currently available (Roll drops out in trends, and the blend adapts). High fragility = impact-driven, reversible tape; low = deep, informed. A plain-language read suggests trusting breakouts less and fades more when fragility is high — as context, not a signal.
The map
Bars that trade unusually large volume leave a horizontal liquidity level where size changed hands. Each level is tinted by the fragility state at the moment it formed: warm = it printed in a thin/impact-driven tape (a weaker level, more likely to be swept); cool = it printed in a deep/informed tape (sturdier). So the map shows not just where liquidity sits but how trustworthy each pocket is.
How to use it
Add to any liquid symbol/timeframe; defaults suit index futures — change the price/volume sources for other markets.
Glance at the fragility lane — the thin strip at the pane bottom: red = thin/fragile, green = deep/solid, gray = normal. Risk-semantic colors (danger/safe), never direction. That strip alone answers "how careful should I be" for a non-technical user.
States are dwell-filtered (standard anti-chattering): a new THIN/DEEP/NORMAL is announced only after surviving a set number of bars, so the read doesn't flip-flop. STABILITY shows how settled it is; PENDING shows a forming state with a countdown. The cost is a few bars of lag — stated and adjustable.
The HTF STACK row shows the raw fragility state on three higher timeframes derived as multiples of the chart (defaults 3×, 5×, 15× — a 5m chart reads 15m/25m/75m automatically). ✓ green = all timeframes agree on the same actionable state; ⚠ amber = a higher timeframe reads the opposite state.
Read the dashboard: DEEP / NORMAL / THIN, the three measures' ranks, and a suggested size factor. As it turns THIN, treat moves as more reversible: size down, favour fades over breakout-chasing.
Use the rails as liquidity references coloured by trust — a warm rail formed in fragile conditions; a cool rail in solid ones.
Pairs with Order-Flow Criticality: that tool asks whether flow is self-exciting (endogenous); this asks whether the book is thin (impactable). Both elevated together is the genuinely fragile state.
What makes it original
Retail liquidity tools draw where volume traded. This one weights each level and the whole tape by how impactable it is, using three peer-reviewed microstructure estimators computed from bar data, self-calibrated, and — crucially — honest about when the Roll model doesn't apply. Reframing a liquidity map from "where is liquidity" to "how fragile is liquidity" is the contribution.
Concept credits
Price impact of order flow (lambda) — A. S. Kyle (1985). Illiquidity ratio — Y. Amihud (2002). Implied effective spread from serial covariance — R. Roll (1984). Square-root impact refinement — J. Hasbrouck. Fragility framing — general market-microstructure literature. Implementation and charting design are the author's own.
Important disclaimer
Research and education only. Not financial advice, not a signal service, not a guarantee of future results. These are proxies estimated from bar data, not order-book truth, and they do not predict direction. Validate independently and manage your own risk.
Release Notes
v1.1 — Finishing pass (no engine change)- Cleared a Pine warning (CW10004): the fragility index called ta.ema from inside a "skip while
warming up" check (chart and higher-timeframe). It now runs every bar via a seed-on-first-valid
EMA that reproduces the exact same output after warm-up — only the warning is gone.
- Added a Data Window (EXP_) export bus so the fragility index, its Kyle/Amihud/Roll component ranks
and the liquidity state can feed other scripts via input.source().
- Added the MPL-2.0 licence header.
- No change to the Kyle/Amihud/Roll engine, the liquidity state, the level marking, the
multi-timeframe reads or the dashboard — everyday behaviour is identical.
Descriptive liquidity/risk-mapping tool, not investment advice.
Open-source script
In true TradingView spirit, the creator of this script has made it open-source, so that traders can review and verify its functionality. Kudos to the author! While you can use it for free, remember that republishing the code is subject to our House Rules.
Disclaimer
The information and publications are not meant to be, and do not constitute, financial, investment, trading, or other types of advice or recommendations supplied or endorsed by TradingView. Read more in the Terms of Use.
Open-source script
In true TradingView spirit, the creator of this script has made it open-source, so that traders can review and verify its functionality. Kudos to the author! While you can use it for free, remember that republishing the code is subject to our House Rules.
Disclaimer
The information and publications are not meant to be, and do not constitute, financial, investment, trading, or other types of advice or recommendations supplied or endorsed by TradingView. Read more in the Terms of Use.