# Elastic Volume-weighted MA A Trend concept (Moving-average lineage) in the LuxAlgo Library, with 1 indicator implementation. ## What is an Elastic Volume-weighted MA? The elastic volume-weighted moving average (eVWMA), introduced by Christian Fries, is a recursive average in which volume sets each bar's influence. Each update scales the prior value by (N minus volume) over N and adds price scaled by volume over N, where N is a chosen volume budget. Structurally it is an [EMA](https://www.luxalgo.com/library/concept/ema/) whose smoothing constant is the bar's share of that budget instead of a fixed number: heavy bars move it sharply, quiet bars barely move it, and a zero-volume bar leaves it unchanged. Fries published the method in Technical Analysis of Stocks & Commodities in 2001, starting from a criticism of conventional averages: an [SMA](https://www.luxalgo.com/library/concept/sma/) or EMA runs on a clock of bars, so an illiquid afternoon counts as much as a frantic open. The eVWMA instead measures its memory in shares or contracts changing hands; a bar transacting ten percent of the budget rewrites ten percent of the line, whatever the calendar says. Fries proposed setting N to the number of shares outstanding, under a model in which each trade randomly replaces existing holdings; the line then approximates the average price at which the current shareholder base acquired its shares. That makes the eVWMA a cost-basis reading, closer in spirit to an anchored volume-weighted average price than to a fixed-window average. Where float data does not exist, implementations substitute a multiple of recent cumulative volume, and that choice dominates the line's speed. The result is an average that self-regulates across regimes without retuning: in a fast, high-participation market it behaves like a short average and hugs price, while in a dull one it lengthens, refusing to chase drift on thin trade. That places it alongside adaptive designs such as the [adaptive-lookback MA](https://www.luxalgo.com/library/concept/adaptive-lookback-ma/), though it adapts to participation rather than volatility. Community implementations range from everget's straight port to LazyBear's envelope build and Spreadburn's trend-colored variant. ## How to identify the eVWMA on a chart The eVWMA plots as a single overlay line, so identification is less about shape and more about recognizing its volume-driven behavior. 1. Apply an eVWMA indicator to the price panel; it renders as a smooth overlay comparable to an exponential average of moderate length. 2. Watch high-volume bars: the line jumps toward price far more than a fixed-period average would, since a heavy bar consumes a big share of the budget. 3. Watch quiet stretches: the line flattens and glides, staying put through low-volume drift and thin sessions. 4. Overlay a conventional average of similar speed; the two track closely while volume is steady and separate sharply after volume shocks, the eVWMA's signature. 5. Check the volume budget N (shares outstanding, or a lookback times a multiplier); that single input decides whether the line reads fast or slow. ## How it's calculated A moving average whose smoothing weight on each bar is that bar's share of recent volume rather than a fixed constant. ``` N_t = Σ V_i, sum over the last n bars ending at t eVWMA_t = ((N_t - V_t) × eVWMA_prev + V_t × P_t) / N_t On the first bar, seed eVWMA_t = P_t P_t: source price at bar t (default close) V_t: volume at bar t V_i: volume at bar i inside the lookback window i: bar index inside the stated lookback window t: current bar index n: volume lookback length (commonly 20) N_t: volume denominator, the total volume over the last n bars eVWMA_t: elastic volume weighted moving average eVWMA_prev: eVWMA on the prior bar ``` Published by Christian Fries in 2001; the original sets N to the instrument's share float, and platforms commonly substitute an n-bar volume sum. Each bar replaces a volume-proportional fraction of the prior average with the current price, so the average adapts quickly on heavy volume and barely moves on thin volume. ## How traders use it - As a participation-weighted trend line: slope, side-of-line and crossover logic all work as with any average, with the property that only volume-backed moves relocate the line quickly. - As a cost-basis proxy: with a float-scale budget, price stretched far above the eVWMA is read as holders sitting on large open profits, a condition worth knowing, though not a timing signal by itself. - As a self-adjusting base for bands: envelope versions project percentage bands around the line, an [MA envelope](https://www.luxalgo.com/library/concept/ma-envelope/) whose center responds to activity instead of needing a period tuned per market. - In crossover systems: a fast and a slow eVWMA, or an eVWMA against a conventional average, give [moving average crossovers](https://www.luxalgo.com/library/concept/moving-average-crossovers/) that thin-trade drift is less able to trigger, filtering [breakout](https://www.luxalgo.com/library/concept/breakout/) attempts that lack participation. - As dynamic support and resistance: in trending markets, pullbacks toward a rising eVWMA are watched for continuation entries, the standard [dynamic S/R via MA](https://www.luxalgo.com/library/concept/dynamic-s-r-via-ma/) playbook run on a volume-aware line. ## eVWMA vs other moving averages - **VWMA** (https://www.luxalgo.com/library/concept/vwma/): The VWMA weights the last N bars by raw volume and forgets anything older than the window. The eVWMA has no window: old prices fade gradually, at a rate set by subsequent traded volume rather than by bar count. - **EMA** (https://www.luxalgo.com/library/concept/ema/): An EMA applies the same smoothing constant every bar, so time alone decays old prices. The eVWMA's constant is the bar's volume divided by the budget, so decay happens only as real trade occurs; the two are identical in form but behave very differently around volume spikes. - **Adaptive-lookback MA** (https://www.luxalgo.com/library/concept/adaptive-lookback-ma/): Averages in the KAMA lineage modulate their speed using volatility or trend-efficiency measures computed from price itself. The eVWMA adapts using volume, an input external to price, so it accelerates on participation rather than on movement. ## FAQ ### What should N be in the eVWMA formula? Fries' original used shares outstanding, which makes the line a cost-basis approximation for that stock. Where no float exists (crypto, forex, futures), implementations commonly use cumulative volume over a lookback, sometimes scaled by a multiplier. Larger budgets produce a smoother, slower line. There is no universal default, and the budget plays the role a period plays in ordinary averages, so check which convention a given tool uses. ### Is the eVWMA the same as VWAP? No. A session VWAP is a cumulative average of volume-weighted price that resets each session, and anchored variants expand from an event. The eVWMA never resets: it is recursive, with exponential-style decay whose speed depends on traded volume. The two can track each other closely while volume is steady, then separate sharply around volume shocks. ### Is the eVWMA better than the VWMA? Neither dominates. The [VWMA](https://www.luxalgo.com/library/concept/vwma/) is simpler to reason about and strictly bounded by its window, while the eVWMA carries information forward indefinitely and never shows the jolt of an old heavy bar dropping out of the window. Which behavior helps depends on the strategy and holding period, so test both on the market in question. ### Does the eVWMA work on forex and other markets without true volume? Spot forex has no consolidated tape, so platforms feed the formula tick volume, a count of price updates. Tick volume tracks activity but is not shares traded, so the cost-basis interpretation is lost; the line still works as an activity-weighted average with a noisier weighting input. ### What happens to the eVWMA on a zero-volume bar? The update multiplies the prior value by (N minus 0) over N and adds nothing, so the line is exactly unchanged. That makes it robust to halts, holidays, and empty sessions, where a fixed-constant average would still pull toward whatever price printed on the inactive bar. ### Can eVWMA crossovers be used as trade signals? Yes, in the same way as any average pair, with the usual caveat that crossover systems whipsaw in ranges. Volume weighting reduces crosses caused by thin-trade noise but does not remove chop, so many users add a regime check such as a [trend regime label](https://www.luxalgo.com/library/concept/trend-regime-label/) before acting on a cross. ## Implementations in the Library - Elastic Volume-weighted MA (LuxAlgo): https://www.luxalgo.com/library/indicator/elastic-volume-weighted-ma/ ## Related concepts - SMA: https://www.luxalgo.com/library/concept/sma/ - EMA: https://www.luxalgo.com/library/concept/ema/ - Adaptive-lookback MA: https://www.luxalgo.com/library/concept/adaptive-lookback-ma/ - MA Envelope: https://www.luxalgo.com/library/concept/ma-envelope/ - SWMA: https://www.luxalgo.com/library/concept/swma/ - RMA: https://www.luxalgo.com/library/concept/rma/ - HMA: https://www.luxalgo.com/library/concept/hma/ - KAMA: https://www.luxalgo.com/library/concept/kama/ - JMA: https://www.luxalgo.com/library/concept/jma/ - ZLEMA: https://www.luxalgo.com/library/concept/zlema/ --- Source: https://www.luxalgo.com/library/concept/elastic-volume-weighted-ma/ (LuxAlgo Library, the encyclopedia of trading & technical analysis). Free to use with attribution: https://www.luxalgo.com/library/license/